Preserve direct-serve redirects for blob HEAD requests

.github/workflows/ci.yml

@@ -17,12 +17,12 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           persist-credentials: false
 
       - name: Set up Go
-        uses: actions/setup-go@b7ad1dad31e06c5925ef5d2fc7ad053ef454303e # v7.0.0
+        uses: actions/setup-go@924ae3a1cded613372ab5595356fb5720e22ba16 # v6.5.0
         with:
           go-version: ${{ matrix.go-version }}
 
@@ -35,12 +35,12 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           persist-credentials: false
 
       - name: Set up Go
-        uses: actions/setup-go@b7ad1dad31e06c5925ef5d2fc7ad053ef454303e # v7.0.0
+        uses: actions/setup-go@924ae3a1cded613372ab5595356fb5720e22ba16 # v6.5.0
         with:
           go-version: '1.25'
 

.github/workflows/publish.yml

@@ -20,12 +20,12 @@ jobs:
       contents: read
     steps:
       - name: Check out the repo
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0
         with:
           persist-credentials: false
 
       - name: Log in to the Container registry
-        uses: docker/login-action@06fb636fac595d6fb4b28a5dfcb21a6f5091859c
+        uses: docker/login-action@c99871dec2022cc055c062a10cc1a1310835ceb4
         with:
           registry: ghcr.io
           username: ${{ github.actor }}

.github/workflows/release.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           fetch-depth: 0
           persist-credentials: false
@@ -22,7 +22,7 @@ jobs:
       - uses: sigstore/cosign-installer@6f9f17788090df1f26f669e9d70d6ae9567deba6 # v4.1.2
 
       - name: Set up Go
-        uses: actions/setup-go@b7ad1dad31e06c5925ef5d2fc7ad053ef454303e # v7.0.0
+        uses: actions/setup-go@924ae3a1cded613372ab5595356fb5720e22ba16 # v6.5.0
         with:
           go-version-file: go.mod
           cache: false

.github/workflows/swagger.yml

@@ -12,12 +12,12 @@ jobs:
   swagger:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           persist-credentials: false
 
       - name: Set up Go
-        uses: actions/setup-go@b7ad1dad31e06c5925ef5d2fc7ad053ef454303e # v7.0.0
+        uses: actions/setup-go@924ae3a1cded613372ab5595356fb5720e22ba16 # v6.5.0
         with:
           go-version: '1.25'
 

.github/workflows/zizmor.yml

@@ -21,9 +21,9 @@ jobs:
       security-events: write
     steps:
       - name: Checkout
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           persist-credentials: false
 
       - name: Run zizmor
-        uses: zizmorcore/zizmor-action@6fc4b006235f201fdab3722e17240ab420d580e5 # v0.6.1
+        uses: zizmorcore/zizmor-action@192e21d79ab29983730a13d1382995c2307fbcaa # v0.5.7

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.26.5-alpine AS builder
+FROM golang:1.26.4-alpine AS builder
 
 WORKDIR /src
 

config.example.yaml

@@ -96,7 +96,8 @@ upstream:
   cargo_download: "https://static.crates.io/crates"
 
   # Authentication for upstream registries
-  # Keys are URL prefixes matched against request URLs.
+  # Keys are absolute URL scopes. Scheme, host, effective port, and path
+  # segment boundaries must match; the longest matching scope wins.
   # Values can reference environment variables using ${VAR_NAME} syntax.
   #
   # Supported auth types:
@@ -168,8 +169,7 @@ cooldown:
   #   npm: "7d"
   #   cargo: "0"
 
-  # Per-package overrides (keyed by PURL). Keys are normalized, so npm scopes
+  # Per-package overrides (keyed by PURL)
-  # may use either @scope or the canonical %40scope form.
   # packages:
   #   "pkg:npm/lodash": "0"
   #   "pkg:npm/@babel/core": "14d"

docs/architecture.md

@@ -240,6 +240,8 @@ Fetches artifacts from upstream registries.
 - Exponential backoff retry on 429 (rate limit) and 5xx errors
 - Returns streaming reader (doesn't load into memory)
 - Configurable user-agent
+- Shares an authentication-aware transport with metadata requests so URL-scoped credentials apply consistently
+- Discovers and caches scoped OCI Bearer tokens from registry challenges
 
 **Resolver:**
 - Determines download URL for a package/version
@@ -351,6 +353,7 @@ Eviction can be implemented as:
 - Fresh data - new versions visible immediately
 - Metadata is small, upstream fetch is fast
 - Set `cache_metadata: true` or use the mirror command to enable metadata caching for offline use via the `metadata_cache` table
+- OCI manifests are the exception: they are cached automatically so previously fetched images remain pullable when the registry or token service is unavailable
 
 **Why stream artifacts?**
 - Memory efficient - don't load large files into RAM

docs/configuration.md

@@ -123,7 +123,9 @@ upstream:
 
 ## Authentication
 
-Configure authentication for private upstream registries. Auth is matched by URL prefix, and credentials can reference environment variables using `${VAR_NAME}` syntax.
+Configure authentication for private upstream registries. The same authentication-aware client is used for metadata and artifact downloads, and credentials can reference environment variables using `${VAR_NAME}` syntax.
+
+OCI registries that return a Bearer challenge from a `/v2/{repository}/…` endpoint are handled automatically. The proxy discovers the token realm from `WWW-Authenticate`, applies any configured credentials for the token URL, and reuses the scoped token until shortly before it expires.
 
 ### Bearer Token
 
@@ -172,7 +174,7 @@ upstream:
 
 ### URL Matching
 
-Auth configs are matched by URL prefix. The longest matching prefix wins, so you can configure different credentials for different paths:
+Auth keys must be absolute URLs. Matching compares the scheme, host, effective port, and path-segment prefix, preventing credentials for `registry.example.com` from being sent to a lookalike host such as `registry.example.com.evil.test`. The longest matching scope wins, so you can configure different credentials for different paths:
 
 ```yaml
 upstream:
@@ -234,8 +236,6 @@ cooldown:
 
 Durations support days (`7d`), hours (`48h`), and minutes (`30m`). Set to `0` to disable.
 
-Package PURL keys are normalized to canonical form before matching, so `pkg:npm/@babel/core` and `pkg:npm/%40babel/core` are equivalent, as are `pkg:pypi/Django` and `pkg:pypi/django`. If both forms configure the same package, the canonical entry wins.
-
 Resolution order: package override, then ecosystem override, then global default. This lets you set a conservative default while exempting trusted packages.
 
 Currently supported for npm, PyPI, pub.dev, Composer, Cargo, NuGet, Conda, RubyGems, and Hex. These ecosystems include publish timestamps in their metadata.
@@ -246,6 +246,8 @@ Note: Hex cooldown requires disabling registry signature verification since the
 
 By default the proxy fetches metadata fresh from upstream on every request. Enable `cache_metadata` to store metadata responses in the database and storage backend for offline fallback. When upstream is unreachable, the proxy serves the last cached copy. ETag-based revalidation avoids re-downloading unchanged metadata.
 
+OCI manifests are always cached because cached image blobs cannot be pulled without their manifests. Digest-addressed manifests are immutable and served directly from cache. Tag-addressed manifests follow `metadata_ttl`, revalidate when stale, and fall back to the last cached response when the registry is unavailable.
+
 ```yaml
 cache_metadata: true
 ```

go.mod

@@ -5,18 +5,18 @@ go 1.25.6
 require (
 	github.com/BurntSushi/toml v1.6.0
 	github.com/CycloneDX/cyclonedx-go v0.11.0
-	github.com/git-pkgs/archives v0.3.1
+	github.com/git-pkgs/archives v0.3.0
 	github.com/git-pkgs/cooldown v0.1.1
-	github.com/git-pkgs/enrichment v0.6.4
+	github.com/git-pkgs/enrichment v0.4.1
-	github.com/git-pkgs/purl v0.1.15
+	github.com/git-pkgs/purl v0.1.13
-	github.com/git-pkgs/registries v0.6.4
+	github.com/git-pkgs/registries v0.6.2
 	github.com/git-pkgs/spdx v0.1.4
-	github.com/git-pkgs/vers v0.3.0
+	github.com/git-pkgs/vers v0.2.6
-	github.com/git-pkgs/vulns v0.2.1
+	github.com/git-pkgs/vulns v0.1.6
-	github.com/go-chi/chi/v5 v5.3.1
+	github.com/go-chi/chi/v5 v5.3.0
 	github.com/jmoiron/sqlx v1.4.0
 	github.com/lib/pq v1.12.3
-	github.com/prometheus/client_golang v1.24.0
+	github.com/prometheus/client_golang v1.23.2
 	github.com/prometheus/client_model v0.6.2
 	github.com/spdx/tools-golang v0.5.7
 	github.com/swaggo/swag v1.16.6
@@ -24,7 +24,7 @@ require (
 	golang.org/x/sync v0.22.0
 	google.golang.org/protobuf v1.36.11
 	gopkg.in/yaml.v3 v3.0.1
-	modernc.org/sqlite v1.55.0
+	modernc.org/sqlite v1.53.0
 )
 
 require (
@@ -115,7 +115,7 @@ require (
 	github.com/denis-tingaikin/go-header v0.5.0 // indirect
 	github.com/dlclark/regexp2 v1.11.5 // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect
-	github.com/ecosyste-ms/ecosystems-go v0.4.0 // indirect
+	github.com/ecosyste-ms/ecosystems-go v0.2.0 // indirect
 	github.com/ettle/strcase v0.2.0 // indirect
 	github.com/facebookgo/clock v0.0.0-20150410010913-600d898af40a // indirect
 	github.com/fatih/color v1.18.0 // indirect
@@ -217,16 +217,15 @@ require (
 	github.com/nishanths/exhaustive v0.12.0 // indirect
 	github.com/nishanths/predeclared v0.2.2 // indirect
 	github.com/nunnatsa/ginkgolinter v0.23.0 // indirect
-	github.com/oapi-codegen/nullable v1.1.0 // indirect
+	github.com/oapi-codegen/runtime v1.4.1 // indirect
-	github.com/oapi-codegen/runtime v1.6.0 // indirect
 	github.com/package-url/packageurl-go v0.1.6 // indirect
 	github.com/pandatix/go-cvss v0.6.2 // indirect
 	github.com/pelletier/go-toml v1.9.5 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
 	github.com/pkg/browser v0.0.0-20240102092130-5ac0b6a4141c // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/prometheus/common v0.70.0 // indirect
+	github.com/prometheus/common v0.67.5 // indirect
-	github.com/prometheus/procfs v0.21.1 // indirect
+	github.com/prometheus/procfs v0.20.1 // indirect
 	github.com/quasilyte/go-ruleguard v0.4.5 // indirect
 	github.com/quasilyte/go-ruleguard/dsl v0.3.23 // indirect
 	github.com/quasilyte/gogrep v0.5.0 // indirect
@@ -266,7 +265,7 @@ require (
 	github.com/timonwong/loggercheck v0.11.0 // indirect
 	github.com/tomarrell/wrapcheck/v2 v2.12.0 // indirect
 	github.com/tommy-muehle/go-mnd/v2 v2.5.1 // indirect
-	github.com/ulikunitz/xz v0.5.16 // indirect
+	github.com/ulikunitz/xz v0.5.15 // indirect
 	github.com/ultraware/funlen v0.2.0 // indirect
 	github.com/ultraware/whitespace v0.2.0 // indirect
 	github.com/urfave/cli/v2 v2.3.0 // indirect
@@ -290,25 +289,25 @@ require (
 	go.opentelemetry.io/otel/trace v1.44.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	go.uber.org/zap v1.27.1 // indirect
-	go.yaml.in/yaml/v2 v2.4.4 // indirect
+	go.yaml.in/yaml/v2 v2.4.3 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/crypto v0.53.0 // indirect
 	golang.org/x/exp v0.0.0-20260218203240-3dfff04db8fa // indirect
 	golang.org/x/exp/typeparams v0.0.0-20260209203927-2842357ff358 // indirect
-	golang.org/x/mod v0.37.0 // indirect
+	golang.org/x/mod v0.36.0 // indirect
 	golang.org/x/net v0.56.0 // indirect
 	golang.org/x/oauth2 v0.36.0 // indirect
-	golang.org/x/sys v0.47.0 // indirect
+	golang.org/x/sys v0.46.0 // indirect
 	golang.org/x/text v0.38.0 // indirect
-	golang.org/x/tools v0.47.0 // indirect
+	golang.org/x/tools v0.45.0 // indirect
 	golang.org/x/xerrors v0.0.0-20240903120638-7835f813f4da // indirect
 	google.golang.org/api v0.272.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20260316180232-0b37fe3546d5 // indirect
-	google.golang.org/grpc v1.82.1 // indirect
+	google.golang.org/grpc v1.81.1 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	honnef.co/go/tools v0.7.0 // indirect
-	modernc.org/libc v1.74.1 // indirect
+	modernc.org/libc v1.73.4 // indirect
 	modernc.org/mathutil v1.7.1 // indirect
 	modernc.org/memory v1.11.0 // indirect
 	mvdan.cc/gofumpt v0.9.2 // indirect

go.sum

@@ -66,8 +66,8 @@ github.com/CycloneDX/cyclonedx-go v0.11.0 h1:GokP8FiRC+foiuwWhSSLpSD5H4hSWtGnR3w
 github.com/CycloneDX/cyclonedx-go v0.11.0/go.mod h1:vUvbCXQsEm48OI6oOlanxstwNByXjCZ2wuleUlwGEO8=
 github.com/Djarvur/go-err113 v0.1.1 h1:eHfopDqXRwAi+YmCUas75ZE0+hoBHJ2GQNLYRSxao4g=
 github.com/Djarvur/go-err113 v0.1.1/go.mod h1:IaWJdYFLg76t2ihfflPZnM1LIQszWOsFDh2hhhAVF6k=
-github.com/GoogleCloudPlatform/opentelemetry-operations-go/detectors/gcp v1.32.0 h1:rIkQfkCOVKc1OiRCNcSDD8ml5RJlZbH/Xsq7lbpynwc=
+github.com/GoogleCloudPlatform/opentelemetry-operations-go/detectors/gcp v1.31.0 h1:DHa2U07rk8syqvCge0QIGMCE1WxGj9njT44GH7zNJLQ=
-github.com/GoogleCloudPlatform/opentelemetry-operations-go/detectors/gcp v1.32.0/go.mod h1:RD2SsorTmYhF6HkTmDw7KmPYQk8OBYwTkuasChwv7R4=
+github.com/GoogleCloudPlatform/opentelemetry-operations-go/detectors/gcp v1.31.0/go.mod h1:P4WPRUkOhJC13W//jWpyfJNDAIpvRbAUIYLX/4jtlE0=
 github.com/GoogleCloudPlatform/opentelemetry-operations-go/exporter/metric v0.55.0 h1:UnDZ/zFfG1JhH/DqxIZYU/1CUAlTUScoXD/LcM2Ykk8=
 github.com/GoogleCloudPlatform/opentelemetry-operations-go/exporter/metric v0.55.0/go.mod h1:IA1C1U7jO/ENqm/vhi7V9YYpBsp+IMyqNrEN94N7tVc=
 github.com/GoogleCloudPlatform/opentelemetry-operations-go/internal/resourcemapping v0.55.0 h1:0s6TxfCu2KHkkZPnBfsQ2y5qia0jl3MMrmBhu3nCOYk=
@@ -217,8 +217,8 @@ github.com/dlclark/regexp2 v1.11.5 h1:Q/sSnsKerHeCkc/jSTNq1oCm7KiVgUMZRDUoRu0JQZ
 github.com/dlclark/regexp2 v1.11.5/go.mod h1:DHkYz0B9wPfa6wondMfaivmHpzrQ3v9q8cnmRbL6yW8=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
-github.com/ecosyste-ms/ecosystems-go v0.4.0 h1:5A+zF+XWT8sYYYjlc2/tI1SmiDGzbHLyT9CapVc5dGA=
+github.com/ecosyste-ms/ecosystems-go v0.2.0 h1:Nhpg54C+St8Sd/mf8bNJmQqx35ZgHw33TfFoxaXMQI8=
-github.com/ecosyste-ms/ecosystems-go v0.4.0/go.mod h1:FVswCrp3DQkur1HjVqfDF/gYrDSEmiFflntcB1G0DbA=
+github.com/ecosyste-ms/ecosystems-go v0.2.0/go.mod h1:CCdzT1iAZirbEZAbFSnWpK88eKKaIWex7gjtZ0UudXA=
 github.com/envoyproxy/go-control-plane v0.14.0 h1:hbG2kr4RuFj222B6+7T83thSPqLjwBIfQawTkC++2HA=
 github.com/envoyproxy/go-control-plane/envoy v1.37.0 h1:u3riX6BoYRfF4Dr7dwSOroNfdSbEPe9Yyl09/B6wBrQ=
 github.com/envoyproxy/go-control-plane/envoy v1.37.0/go.mod h1:DReE9MMrmecPy+YvQOAOHNYMALuowAnbjjEMkkWOi6A=
@@ -244,30 +244,30 @@ github.com/fzipp/gocyclo v0.6.0 h1:lsblElZG7d3ALtGMx9fmxeTKZaLLpU8mET09yN4BBLo=
 github.com/fzipp/gocyclo v0.6.0/go.mod h1:rXPyn8fnlpa0R2csP/31uerbiVBugk5whMdlyaLkLoA=
 github.com/ghostiam/protogetter v0.3.20 h1:oW7OPFit2FxZOpmMRPP9FffU4uUpfeE/rEdE1f+MzD0=
 github.com/ghostiam/protogetter v0.3.20/go.mod h1:FjIu5Yfs6FT391m+Fjp3fbAYJ6rkL/J6ySpZBfnODuI=
-github.com/git-pkgs/archives v0.3.1 h1:GKUuw++0YXAAElxweVHiR4AaSShKKYoVQmyxlF5blG4=
+github.com/git-pkgs/archives v0.3.0 h1:iXKyO83jEFub1PGEDlHmk2tQ7XeV5LySTc0sEkH3x78=
-github.com/git-pkgs/archives v0.3.1/go.mod h1:408oQv3FxLCtePa33zp3sg3njXnwH74vnHZFxkRqoPo=
+github.com/git-pkgs/archives v0.3.0/go.mod h1:LTJ1iQVFA7otizWMOyiI82NYVmyBWAPRzwu/e30rcXU=
 github.com/git-pkgs/cooldown v0.1.1 h1:9OqqzCB8gANz/y44SmqGD0Jp8Qtu81D1sCbKl6Ehg7w=
 github.com/git-pkgs/cooldown v0.1.1/go.mod h1:v7APuK/UouTiu8mWQZbdDmj7DfxxkGUeuhjaRB5gv9E=
-github.com/git-pkgs/enrichment v0.6.4 h1:mGrfenttwmcUfPXRkWpB0wBJiiGj55ltniUh66Pq4bU=
+github.com/git-pkgs/enrichment v0.4.1 h1:A8BKs0XwvpF1sF5qviZy4fkJAe18qB9OgpbRnmwnT34=
-github.com/git-pkgs/enrichment v0.6.4/go.mod h1:zz1vPUak/w8Jhajll0KDRN2MjKaEYeCzQTxumWnVhqY=
+github.com/git-pkgs/enrichment v0.4.1/go.mod h1:stHqZUitV9ZkwACqHzBysLMSe6T4QZn81hxTdSroNhM=
 github.com/git-pkgs/packageurl-go v0.3.1 h1:WM3RBABQZLaRBxgKyYughc3cVBE8KyQxbSC6Jt5ak7M=
 github.com/git-pkgs/packageurl-go v0.3.1/go.mod h1:rcIxiG37BlQLB6FZfgdj9Fm7yjhRQd3l+5o7J0QPAk4=
 github.com/git-pkgs/pom v0.1.5 h1:TGT8Az2OMxGWsXnSagtUMGzZm7Oax8HrSCteA+mi0qY=
 github.com/git-pkgs/pom v0.1.5/go.mod h1:ufdMBe1lKzqOeP9IUb9NPZ458xKV8E8NvuyBMxOfwIk=
-github.com/git-pkgs/purl v0.1.15 h1:iQ3clh0Cw41rkM0rf24B7ShnN9Z+UtLMAFlNDUs+Qd4=
+github.com/git-pkgs/purl v0.1.13 h1:at8BU6vnP5oonHFHAPA064BzgRqij+SZcOUDgNT2DC8=
-github.com/git-pkgs/purl v0.1.15/go.mod h1:PqCLVBDeZrZgHysR803/AntMELgIr2LFZVNCcwLH2m0=
+github.com/git-pkgs/purl v0.1.13/go.mod h1:8oCcdcYZA/e1B33e7Ylju6azboTKjdqf3ybcbQj6I/o=
-github.com/git-pkgs/registries v0.6.4 h1:Kq/KlStjaQyE83UXT/tKuzCrIzc4keGeBjtroMqgoHA=
+github.com/git-pkgs/registries v0.6.2 h1:26G5zW6Q7x1CSfNkaEqEjRMJiA4JwfdKOCJ7Qm+u0a8=
-github.com/git-pkgs/registries v0.6.4/go.mod h1:YkGHbxHIe2Ha/ROH6zNkS5PJUUoa9g0Ti/s2XhZnrak=
+github.com/git-pkgs/registries v0.6.2/go.mod h1:GR0Bu6nC3NQe6f7lfDoEVqAnoQkMocf4M98B12a7B3E=
 github.com/git-pkgs/spdx v0.1.4 h1:eQ0waEV3uUeItpWAOvdN1K1rL9hTgsU7fF74r1mDXMs=
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@@ -422,8 +422,8 @@ github.com/kisielk/errcheck v1.9.0 h1:9xt1zI9EBfcYBvdU1nVrzMzzUPUtPKs9bVSIM3TAb3
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-github.com/klauspost/compress v1.19.0 h1:sXLILfc9jV2QYWkzFOPWStmcUVH2RHEB1JCdY2oVvCQ=
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-github.com/klauspost/compress v1.19.0/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
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@@ -512,8 +512,8 @@ github.com/nunnatsa/ginkgolinter v0.23.0 h1:x3o4DGYOWbBMP/VdNQKgSj+25aJKx2Pe6lHr
 github.com/nunnatsa/ginkgolinter v0.23.0/go.mod h1:9qN1+0akwXEccwV1CAcCDfcoBlWXHB+ML9884pL4SZ4=
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-github.com/oapi-codegen/runtime v1.6.0 h1:7Xx+GlueD6nRuyKoCPzL434Jfi3BetbiJOrzCHp/VPU=
+github.com/oapi-codegen/runtime v1.4.1 h1:9nwLoI+KrWxzbBcp0jO/R8uXqbik/HUyCvPeU68Y/qo=
-github.com/oapi-codegen/runtime v1.6.0/go.mod h1:GwV7hC2hviaMzj+ITfHVRESK5J2W/GefVwIND/bMGvU=
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@@ -541,14 +541,14 @@ github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10 h1:GFCKgm
 github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10/go.mod h1:t/avpk3KcrXxUnYOhZhMXJlSEyie6gQbtLq5NM3loB8=
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-github.com/prometheus/client_golang v1.24.0 h1:5XStIklKuAtJSNpdD3s8XJj/Yv78IQmE1kbNk87JrAI=
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-github.com/prometheus/client_golang v1.24.0/go.mod h1:QcsNdotprC2nS4BTM2ucbcqxd2CeXTEa9jW7zHO9iDE=
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-github.com/prometheus/procfs v0.21.1 h1:GljZCt+zSTS+NZq88cyQ1LjZ+RCHp3uVuabBWA5+OJI=
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-github.com/prometheus/procfs v0.21.1/go.mod h1:aB55Cww9pdSJVHk0hUf0inxWyyjPogFIjmHKYgMKmtY=
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@@ -654,8 +654,8 @@ github.com/tomarrell/wrapcheck/v2 v2.12.0 h1:H/qQ1aNWz/eeIhxKAFvkfIA+N7YDvq6TWVF
 github.com/tomarrell/wrapcheck/v2 v2.12.0/go.mod h1:AQhQuZd0p7b6rfW+vUwHm5OMCGgp63moQ9Qr/0BpIWo=
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-github.com/ulikunitz/xz v0.5.16 h1:ld6NyySjx5lowVKwJvMRLnW5nxKX/xnpSiFYZ/Lxur0=
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-github.com/ulikunitz/xz v0.5.16/go.mod h1:H9Rt/W6/Qj27PGauhQc6nfCDy7vHpzsOThBSaYDoEhw=
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@@ -702,8 +702,8 @@ go.augendre.info/fatcontext v0.9.0 h1:Gt5jGD4Zcj8CDMVzjOJITlSb9cEch54hjRRlN3qDoj
 go.augendre.info/fatcontext v0.9.0/go.mod h1:L94brOAT1OOUNue6ph/2HnwxoNlds9aXDF2FcUntbNw=
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 go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
-go.opentelemetry.io/contrib/detectors/gcp v1.43.0 h1:62yY3dT7/ShwOxzA0RsKRgshBmfElKI4d/Myu2OxDFU=
+go.opentelemetry.io/contrib/detectors/gcp v1.42.0 h1:kpt2PEJuOuqYkPcktfJqWWDjTEd/FNgrxcniL7kQrXQ=
-go.opentelemetry.io/contrib/detectors/gcp v1.43.0/go.mod h1:RyaZMFY7yi1kAs45S6mbFGz8O8rqB0dTY14uzvG4LCs=
+go.opentelemetry.io/contrib/detectors/gcp v1.42.0/go.mod h1:W9zQ439utxymRrXsUOzZbFX4JhLxXU4+ZnCt8GG7yA8=
 go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.67.0 h1:yI1/OhfEPy7J9eoa6Sj051C7n5dvpj0QX8g4sRchg04=
 go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.67.0/go.mod h1:NoUCKYWK+3ecatC4HjkRktREheMeEtrXoQxrqYFeHSc=
 go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.67.0 h1:OyrsyzuttWTSur2qN/Lm0m2a8yqyIjUVBZcxFPuXq2o=
@@ -726,8 +726,8 @@ go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=
 go.uber.org/multierr v1.11.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
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-go.yaml.in/yaml/v2 v2.4.4 h1:tuyd0P+2Ont/d6e2rl3be67goVK4R6deVxCUX5vyPaQ=
+go.yaml.in/yaml/v2 v2.4.3 h1:6gvOSjQoTB3vt1l+CU+tSyi/HOjfOjRLJ4YwYZGwRO0=
-go.yaml.in/yaml/v2 v2.4.4/go.mod h1:gMZqIpDtDqOfM0uNfy0SkpRhvUryYH0Z6wdMYcacYXQ=
+go.yaml.in/yaml/v2 v2.4.3/go.mod h1:zSxWcmIDjOzPXpjlTTbAsKokqkDNAVtZO0WOMiT90s8=
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@@ -755,8 +755,8 @@ golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
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 golang.org/x/mod v0.13.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
-golang.org/x/mod v0.37.0 h1:vF1DjpVEshcIqoEaauuHebaLk1O1forxjxBaVn884JQ=
+golang.org/x/mod v0.36.0 h1:JJjpVx6myfUsUdAzZuOSTTmRE0PfZeNWzzvKrP7amb4=
-golang.org/x/mod v0.37.0/go.mod h1:m8S8VeM9r4dzDwjrKO0a1sZP3YjeMamRRlD+fmR2Q/0=
+golang.org/x/mod v0.36.0/go.mod h1:moc6ELqsWcOw5Ef3xVprK5ul/MvtVvkIXLziUOICjUQ=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
@@ -807,8 +807,8 @@ golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
+golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
-golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
@@ -839,8 +839,8 @@ golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
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 golang.org/x/tools v0.14.0/go.mod h1:uYBEerGOWcJyEORxN+Ek8+TT266gXkNlHdJBwexUsBg=
-golang.org/x/tools v0.47.0 h1:7Kn5x/d1svx/PzryTsqeoZN4TZwqeH5pGWjefhLi/1Q=
+golang.org/x/tools v0.45.0 h1:18qN3FAooORvApf5XjCXgsuayZOEtXf6JK18I3+ONa8=
-golang.org/x/tools v0.47.0/go.mod h1:dFHnyTvFWY212G+h7ZY4Vsp/K3U4/7W9TyVaAul8uCA=
+golang.org/x/tools v0.45.0/go.mod h1:LuUGqqaXcXMEFEruIVJVm5mgDD8vww/z/SR1gQ4uE/0=
 golang.org/x/tools/go/expect v0.1.1-deprecated h1:jpBZDwmgPhXsKZC6WhL20P4b/wmnpsEAGHaNy0n/rJM=
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@@ -857,12 +857,12 @@ google.golang.org/api v0.272.0 h1:eLUQZGnAS3OHn31URRf9sAmRk3w2JjMx37d2k8AjJmA=
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 google.golang.org/genproto v0.0.0-20260316180232-0b37fe3546d5 h1:JNfk58HZ8lfmXbYK2vx/UvsqIL59TzByCxPIX4TDmsE=
 google.golang.org/genproto v0.0.0-20260316180232-0b37fe3546d5/go.mod h1:x5julN69+ED4PcFk/XWayw35O0lf/nGa4aNgODCmNmw=
-google.golang.org/genproto/googleapis/api v0.0.0-20260414002931-afd174a4e478 h1:yQugLulqltosq0B/f8l4w9VryjV+N/5gcW0jQ3N8Qec=
+google.golang.org/genproto/googleapis/api v0.0.0-20260316180232-0b37fe3546d5 h1:CogIeEXn4qWYzzQU0QqvYBM8yDF9cFYzDq9ojSpv0Js=
-google.golang.org/genproto/googleapis/api v0.0.0-20260414002931-afd174a4e478/go.mod h1:C6ADNqOxbgdUUeRTU+LCHDPB9ttAMCTff6auwCVa4uc=
+google.golang.org/genproto/googleapis/api v0.0.0-20260316180232-0b37fe3546d5/go.mod h1:EIQZ5bFCfRQDV4MhRle7+OgjNtZ6P1PiZBgAKuxXu/Y=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478 h1:RmoJA1ujG+/lRGNfUnOMfhCy5EipVMyvUE+KNbPbTlw=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20260316180232-0b37fe3546d5 h1:aJmi6DVGGIStN9Mobk/tZOOQUBbj0BPjZjjnOdoZKts=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20260316180232-0b37fe3546d5/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
-google.golang.org/grpc v1.82.1 h1:NnAxzGRA0677vCa4BUkOAnO5+FfQqVl9iUXeD0IqcGE=
+google.golang.org/grpc v1.81.1 h1:VnnIIZ88UzOOKLukQi+ImGz8O1Wdp8nAGGnvOfEIWQQ=
-google.golang.org/grpc v1.82.1/go.mod h1:yzTZ1TB1Z3SG+LIYaI+WiE8D5+PZ3ArnrSp8zF3+/ZA=
+google.golang.org/grpc v1.81.1/go.mod h1:xGH9GfzOyMTGIOXBJmXt+BX/V0kcdQbdcuwQ/zNw42I=
 google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
 google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
@@ -882,20 +882,20 @@ gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.7.0 h1:w6WUp1VbkqPEgLz4rkBzH/CSU6HkoqNLp6GstyTx3lU=
 honnef.co/go/tools v0.7.0/go.mod h1:pm29oPxeP3P82ISxZDgIYeOaf9ta6Pi0EWvCFoLG2vc=
-modernc.org/cc/v4 v4.29.0 h1:CXgwL8cvxmyzBQZzbSl/6xFtMCryb6u8IOqDci39cgc=
+modernc.org/cc/v4 v4.28.4 h1:Hd/4Es+MBj+/7hSdZaisNyu6bv3V0Dp2MdllyfqaH+c=
-modernc.org/cc/v4 v4.29.0/go.mod h1:OnovgIhbbMXMu1aISnJ0wvVD1KnW+cAUJkIrAWh+kVI=
+modernc.org/cc/v4 v4.28.4/go.mod h1:OnovgIhbbMXMu1aISnJ0wvVD1KnW+cAUJkIrAWh+kVI=
-modernc.org/ccgo/v4 v4.34.6 h1:sBgfIwyN0TQ9C5hwIeuqyeAKyMWnbvj2fvpF4L11uzU=
+modernc.org/ccgo/v4 v4.34.4 h1:OVnSOWQjVKOYkFxoHYB+qQmSHK5gqMqARM+K9DpR/Ws=
-modernc.org/ccgo/v4 v4.34.6/go.mod h1:SZ8YcN9NG7XVsQYdm6jYBvi8PQP1qi+kqB6OhjqI3Fk=
+modernc.org/ccgo/v4 v4.34.4/go.mod h1:qdKqE8FNIYyysougB1RX9MxCzp5oJOcQXSobANJ4TuE=
 modernc.org/fileutil v1.4.0 h1:j6ZzNTftVS054gi281TyLjHPp6CPHr2KCxEXjEbD6SM=
 modernc.org/fileutil v1.4.0/go.mod h1:EqdKFDxiByqxLk8ozOxObDSfcVOv/54xDs/DUHdvCUU=
 modernc.org/gc/v2 v2.6.5 h1:nyqdV8q46KvTpZlsw66kWqwXRHdjIlJOhG6kxiV/9xI=
 modernc.org/gc/v2 v2.6.5/go.mod h1:YgIahr1ypgfe7chRuJi2gD7DBQiKSLMPgBQe9oIiito=
-modernc.org/gc/v3 v3.1.4 h1:2g65LGVSmFQrXeITAw97x7hCRvZFcyE1uDP+7Vng7JI=
+modernc.org/gc/v3 v3.1.3 h1:6QAplYyVO+KdPW3pGnqmJDUxtkec8ooEWvks/hhU3lc=
-modernc.org/gc/v3 v3.1.4/go.mod h1:HFK/6AGESC7Ex+EZJhJ2Gni6cTaYpSMmU/cT9RmlfYY=
+modernc.org/gc/v3 v3.1.3/go.mod h1:HFK/6AGESC7Ex+EZJhJ2Gni6cTaYpSMmU/cT9RmlfYY=
 modernc.org/goabi0 v0.2.0 h1:HvEowk7LxcPd0eq6mVOAEMai46V+i7Jrj13t4AzuNks=
 modernc.org/goabi0 v0.2.0/go.mod h1:CEFRnnJhKvWT1c1JTI3Avm+tgOWbkOu5oPA8eH8LnMI=
-modernc.org/libc v1.74.1 h1:bdR4VTKFMC4966QSNZ05XLGI/VwzVa2kTUX51Dm0riQ=
+modernc.org/libc v1.73.4 h1:+ra4Ui8ngyt8HDcO1FTDPWlkAh6yOdaO2yAoh8MddQA=
-modernc.org/libc v1.74.1/go.mod h1:uH4t5bOx3G3g9Xcmj10YKlTcVISlRDwv8VoQJG9n8Os=
+modernc.org/libc v1.73.4/go.mod h1:DXZ3eO8qMCNn2SnmTNCiC71nJ9Rcq3PsnpU6Vc4rWK8=
 modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
 modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
 modernc.org/memory v1.11.0 h1:o4QC8aMQzmcwCK3t3Ux/ZHmwFPzE6hf2Y5LbkRs+hbI=
@@ -904,8 +904,8 @@ modernc.org/opt v0.2.0 h1:tGyef5ApycA7FSEOMraay9SaTk5zmbx7Tu+cJs4QKZg=
 modernc.org/opt v0.2.0/go.mod h1:03fq9lsNfvkYSfxrfUhZCWPk1lm4cq4N+Bh//bEtgns=
 modernc.org/sortutil v1.2.1 h1:+xyoGf15mM3NMlPDnFqrteY07klSFxLElE2PVuWIJ7w=
 modernc.org/sortutil v1.2.1/go.mod h1:7ZI3a3REbai7gzCLcotuw9AC4VZVpYMjDzETGsSMqJE=
-modernc.org/sqlite v1.55.0 h1:hIFh0MCH0rGinQ/4KYb5/UbCkRkb+UP+OkLCVWa5MTM=
+modernc.org/sqlite v1.53.0 h1:20WG8N9q4ji/dEqGk4uiI0c6OPjSeLTNYGFCc3+7c1M=
-modernc.org/sqlite v1.55.0/go.mod h1:4ntCLuNmnH8+GNqjka1wNg7KJd5/Hi5FYp8K+XQ7GZw=
+modernc.org/sqlite v1.53.0/go.mod h1:xoEpOIpGrgT48H5iiyt/YXPCZPEzlfmfFwtk8Lklw8s=
 modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
 modernc.org/strutil v1.2.1/go.mod h1:EHkiggD70koQxjVdSBM3JKM7k6L0FbGE5eymy9i3B9A=
 modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=

internal/config/config.go

@@ -54,12 +54,10 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
-	"sort"
 	"strconv"
 	"strings"
 	"time"
 
-	"github.com/git-pkgs/purl"
 	"gopkg.in/yaml.v3"
 )
 
@@ -139,38 +137,9 @@ type CooldownConfig struct {
 	Ecosystems map[string]string `json:"ecosystems" yaml:"ecosystems"`
 
 	// Packages overrides the cooldown for specific packages (keyed by PURL).
-	// Valid PURL keys are normalized to canonical form before use.
 	Packages map[string]string `json:"packages" yaml:"packages"`
 }
 
-// NormalizedPackages returns a copy of the package overrides with valid PURL
-// keys in canonical form. An explicitly canonical key wins over an equivalent
-// noncanonical key, and invalid keys are preserved unchanged.
-func (c *CooldownConfig) NormalizedPackages() map[string]string {
-	if c == nil || c.Packages == nil {
-		return nil
-	}
-
-	keys := make([]string, 0, len(c.Packages))
-	for key := range c.Packages {
-		keys = append(keys, key)
-	}
-	sort.Strings(keys)
-
-	normalized := make(map[string]string, len(c.Packages))
-	for _, key := range keys {
-		canonical := key
-		if parsed, err := purl.Parse(key); err == nil {
-			canonical = parsed.String()
-		}
-		if _, exists := normalized[canonical]; exists && key != canonical {
-			continue
-		}
-		normalized[canonical] = c.Packages[key]
-	}
-	return normalized
-}
-
 // StorageConfig configures artifact storage.
 type StorageConfig struct {
 	// URL is the storage backend URL.
@@ -305,23 +274,29 @@ type UpstreamConfig struct {
 	CargoDownload string `json:"cargo_download" yaml:"cargo_download"`
 
 	// Auth configures authentication for upstream registries.
-	// Keys are URL prefixes that are matched against request URLs.
+	// Keys are absolute URL scopes matched by scheme, host, effective port,
+	// and path-segment prefix.
 	// Example: "https://npm.pkg.github.com" matches all requests to that host.
 	Auth map[string]AuthConfig `json:"auth" yaml:"auth"`
 }
 
 // AuthForURL returns the auth config that matches the given URL.
-// Matches are based on URL prefix - the longest matching prefix wins.
+// The longest matching URL scope wins.
 func (u *UpstreamConfig) AuthForURL(url string) *AuthConfig {
 	if u.Auth == nil {
 		return nil
 	}
+	target, err := parseAuthURL(url)
+	if err != nil {
+		return nil
+	}
 
 	var bestMatch *AuthConfig
 	var bestLen int
 
 	for pattern, auth := range u.Auth {
-		if strings.HasPrefix(url, pattern) && len(pattern) > bestLen {
+		configured, err := parseAuthURL(pattern)
+		if err == nil && authURLMatches(configured, target) && len(pattern) > bestLen {
 			a := auth // copy to avoid loop variable capture
 			bestMatch = &a
 			bestLen = len(pattern)
@@ -331,6 +306,45 @@ func (u *UpstreamConfig) AuthForURL(url string) *AuthConfig {
 	return bestMatch
 }
 
+func parseAuthURL(value string) (*url.URL, error) {
+	parsed, err := url.Parse(value)
+	if err != nil || !parsed.IsAbs() || parsed.Hostname() == "" || parsed.Opaque != "" {
+		return nil, fmt.Errorf("invalid authentication URL")
+	}
+	return parsed, nil
+}
+
+func authURLMatches(configured, target *url.URL) bool {
+	if !strings.EqualFold(configured.Scheme, target.Scheme) ||
+		!strings.EqualFold(configured.Hostname(), target.Hostname()) ||
+		authURLPort(configured) != authURLPort(target) {
+		return false
+	}
+	if configured.RawQuery != "" && configured.RawQuery != target.RawQuery {
+		return false
+	}
+
+	configuredPath := strings.TrimSuffix(configured.EscapedPath(), "/")
+	if configuredPath == "" {
+		return true
+	}
+	targetPath := strings.TrimSuffix(target.EscapedPath(), "/")
+	return targetPath == configuredPath || strings.HasPrefix(targetPath, configuredPath+"/")
+}
+
+func authURLPort(value *url.URL) string {
+	if port := value.Port(); port != "" {
+		return port
+	}
+	if strings.EqualFold(value.Scheme, "https") {
+		return "443"
+	}
+	if strings.EqualFold(value.Scheme, "http") {
+		return "80"
+	}
+	return ""
+}
+
 // AuthConfig configures authentication for an upstream registry.
 type AuthConfig struct {
 	// Type is the authentication type: "bearer", "basic", or "header".

internal/config/config_test.go

@@ -363,34 +363,6 @@ cooldown:
 	if cfg.Cooldown.Packages["pkg:npm/@babel/core"] != "14d" {
 		t.Errorf("Cooldown.Packages[@babel/core] = %q, want %q", cfg.Cooldown.Packages["pkg:npm/@babel/core"], "14d")
 	}
-	if got := cfg.Cooldown.NormalizedPackages()["pkg:npm/%40babel/core"]; got != "14d" {
-		t.Errorf("normalized Cooldown.Packages[@babel/core] = %q, want %q", got, "14d")
-	}
-}
-
-func TestCooldownConfigNormalizedPackages(t *testing.T) {
-	rawScoped := "pkg:npm/@typescript/typescript-darwin-arm64"
-	canonicalScoped := "pkg:npm/%40typescript/typescript-darwin-arm64"
-	cfg := CooldownConfig{Packages: map[string]string{
-		rawScoped:       "2d",
-		canonicalScoped: "3d",
-		"not-a-purl":    "4d",
-	}}
-
-	got := cfg.NormalizedPackages()
-
-	if got[canonicalScoped] != "3d" {
-		t.Errorf("canonical scoped package duration = %q, want %q", got[canonicalScoped], "3d")
-	}
-	if _, exists := got[rawScoped]; exists {
-		t.Errorf("raw scoped package key %q was not canonicalized", rawScoped)
-	}
-	if got["not-a-purl"] != "4d" {
-		t.Errorf("invalid PURL duration = %q, want preserved value %q", got["not-a-purl"], "4d")
-	}
-	if cfg.Packages[rawScoped] != "2d" {
-		t.Error("NormalizedPackages mutated the source map")
-	}
 }
 
 func TestLoadCooldownFromEnv(t *testing.T) {
@@ -788,3 +760,45 @@ func TestDatabaseConfigString(t *testing.T) {
 		}
 	}
 }
+
+func TestUpstreamAuthForURLMatchesURLComponents(t *testing.T) {
+	registryAuth := AuthConfig{Type: "bearer", Token: "registry-token"}
+	privateAuth := AuthConfig{Type: "bearer", Token: "private-token"}
+	config := UpstreamConfig{Auth: map[string]AuthConfig{
+		"https://registry.example.com":         registryAuth,
+		"https://registry.example.com/private": privateAuth,
+	}}
+
+	tests := []struct {
+		name      string
+		url       string
+		wantToken string
+	}{
+		{name: "registry root", url: "https://registry.example.com/package", wantToken: "registry-token"},
+		{name: "host is case insensitive", url: "https://REGISTRY.EXAMPLE.COM/package", wantToken: "registry-token"},
+		{name: "longest path match", url: "https://registry.example.com/private/package", wantToken: "private-token"},
+		{name: "exact path match", url: "https://registry.example.com/private", wantToken: "private-token"},
+		{name: "path segment boundary", url: "https://registry.example.com/private-other/package", wantToken: "registry-token"},
+		{name: "lookalike host rejected", url: "https://registry.example.com.evil.test/package"},
+		{name: "different scheme rejected", url: "http://registry.example.com/package"},
+		{name: "different port rejected", url: "https://registry.example.com:8443/package"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			auth := config.AuthForURL(tt.url)
+			if tt.wantToken == "" {
+				if auth != nil {
+					t.Fatalf("AuthForURL() = %+v, want nil", auth)
+				}
+				return
+			}
+			if auth == nil {
+				t.Fatal("AuthForURL() = nil, want authentication")
+			}
+			if auth.Token != tt.wantToken {
+				t.Errorf("token = %q, want %q", auth.Token, tt.wantToken)
+			}
+		})
+	}
+}

internal/database/metadata_cache_test.go

@@ -30,8 +30,12 @@ func TestUpsertAndGetMetadataCache(t *testing.T) {
 		StoragePath: "_metadata/npm/lodash/metadata",
 		ETag:        sql.NullString{String: `"abc123"`, Valid: true},
 		ContentType: sql.NullString{String: "application/json", Valid: true},
-		Size:        sql.NullInt64{Int64: 1024, Valid: true},
+		ContentDigest: sql.NullString{
-		FetchedAt:   sql.NullTime{Time: time.Now(), Valid: true},
+			String: "sha256:0123456789abcdef",
+			Valid:  true,
+		},
+		Size:      sql.NullInt64{Int64: 1024, Valid: true},
+		FetchedAt: sql.NullTime{Time: time.Now(), Valid: true},
 	}
 
 	err := db.UpsertMetadataCache(entry)
@@ -62,6 +66,9 @@ func TestUpsertAndGetMetadataCache(t *testing.T) {
 	if !got.ContentType.Valid || got.ContentType.String != "application/json" {
 		t.Errorf("content_type = %v, want %q", got.ContentType, "application/json")
 	}
+	if !got.ContentDigest.Valid || got.ContentDigest.String != "sha256:0123456789abcdef" {
+		t.Errorf("content_digest = %v, want %q", got.ContentDigest, "sha256:0123456789abcdef")
+	}
 	if !got.Size.Valid || got.Size.Int64 != 1024 {
 		t.Errorf("size = %v, want 1024", got.Size)
 	}
@@ -178,3 +185,47 @@ func TestMetadataCacheTableCreatedByMigration(t *testing.T) {
 		t.Error("metadata_cache table should exist after migration")
 	}
 }
+
+func TestMetadataCacheContentDigestMigrationPreservesExistingRows(t *testing.T) {
+	dbPath := filepath.Join(t.TempDir(), "test.db")
+	db, err := Create(dbPath)
+	if err != nil {
+		t.Fatalf("Create failed: %v", err)
+	}
+	defer func() { _ = db.Close() }()
+
+	if _, err := db.Exec("ALTER TABLE metadata_cache DROP COLUMN content_digest"); err != nil {
+		t.Fatalf("dropping content_digest: %v", err)
+	}
+	if _, err := db.Exec("DELETE FROM migrations WHERE name = ?", "006_add_metadata_content_digest"); err != nil {
+		t.Fatalf("resetting digest migration: %v", err)
+	}
+	if _, err := db.Exec(`
+		INSERT INTO metadata_cache (ecosystem, name, storage_path, content_type, size, fetched_at, created_at, updated_at)
+		VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+	`, "oci-manifest", "cache-key", "_metadata/oci-manifest/cache-key/metadata", "application/json", 2, time.Now(), time.Now(), time.Now()); err != nil {
+		t.Fatalf("inserting legacy cache row: %v", err)
+	}
+
+	if err := db.MigrateSchema(); err != nil {
+		t.Fatalf("MigrateSchema() error = %v", err)
+	}
+	hasDigest, err := db.HasColumn("metadata_cache", "content_digest")
+	if err != nil {
+		t.Fatalf("HasColumn() error = %v", err)
+	}
+	if !hasDigest {
+		t.Fatal("metadata_cache.content_digest was not added")
+	}
+
+	entry, err := db.GetMetadataCache("oci-manifest", "cache-key")
+	if err != nil {
+		t.Fatalf("GetMetadataCache() error = %v", err)
+	}
+	if entry == nil || entry.StoragePath != "_metadata/oci-manifest/cache-key/metadata" {
+		t.Fatalf("existing metadata cache row was not preserved: %#v", entry)
+	}
+	if entry.ContentDigest.Valid {
+		t.Errorf("legacy content digest = %q, want NULL", entry.ContentDigest.String)
+	}
+}

internal/database/queries.go

@@ -894,7 +894,7 @@ func (db *DB) GetMetadataCache(ecosystem, name string) (*MetadataCacheEntry, err
 	var entry MetadataCacheEntry
 	query := db.Rebind(`
 		SELECT id, ecosystem, name, storage_path, etag, content_type,
-		       size, last_modified, fetched_at, created_at, updated_at
+		       content_digest, size, last_modified, fetched_at, created_at, updated_at
 		FROM metadata_cache WHERE ecosystem = ? AND name = ?
 	`)
 	err := db.Get(&entry, query, ecosystem, name)
@@ -914,12 +914,13 @@ func (db *DB) UpsertMetadataCache(entry *MetadataCacheEntry) error {
 	if db.dialect == DialectPostgres {
 		query = `
 			INSERT INTO metadata_cache (ecosystem, name, storage_path, etag, content_type,
-			                            size, last_modified, fetched_at, created_at, updated_at)
+			                            content_digest, size, last_modified, fetched_at, created_at, updated_at)
-			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
+			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)
 			ON CONFLICT(ecosystem, name) DO UPDATE SET
 				storage_path = EXCLUDED.storage_path,
 				etag = EXCLUDED.etag,
 				content_type = EXCLUDED.content_type,
+				content_digest = EXCLUDED.content_digest,
 				size = EXCLUDED.size,
 				last_modified = EXCLUDED.last_modified,
 				fetched_at = EXCLUDED.fetched_at,
@@ -928,12 +929,13 @@ func (db *DB) UpsertMetadataCache(entry *MetadataCacheEntry) error {
 	} else {
 		query = `
 			INSERT INTO metadata_cache (ecosystem, name, storage_path, etag, content_type,
-			                            size, last_modified, fetched_at, created_at, updated_at)
+			                            content_digest, size, last_modified, fetched_at, created_at, updated_at)
-			VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+			VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
 			ON CONFLICT(ecosystem, name) DO UPDATE SET
 				storage_path = excluded.storage_path,
 				etag = excluded.etag,
 				content_type = excluded.content_type,
+				content_digest = excluded.content_digest,
 				size = excluded.size,
 				last_modified = excluded.last_modified,
 				fetched_at = excluded.fetched_at,
@@ -943,7 +945,7 @@ func (db *DB) UpsertMetadataCache(entry *MetadataCacheEntry) error {
 
 	_, err := db.Exec(query,
 		entry.Ecosystem, entry.Name, entry.StoragePath, entry.ETag,
-		entry.ContentType, entry.Size, entry.LastModified, entry.FetchedAt, now, now,
+		entry.ContentType, entry.ContentDigest, entry.Size, entry.LastModified, entry.FetchedAt, now, now,
 	)
 	if err != nil {
 		return fmt.Errorf("upserting metadata cache: %w", err)

internal/database/schema.go

@@ -102,6 +102,7 @@ CREATE TABLE IF NOT EXISTS metadata_cache (
 	storage_path TEXT NOT NULL,
 	etag TEXT,
 	content_type TEXT,
+	content_digest TEXT,
 	size INTEGER,
 	last_modified DATETIME,
 	fetched_at DATETIME,
@@ -202,6 +203,7 @@ CREATE TABLE IF NOT EXISTS metadata_cache (
 	storage_path TEXT NOT NULL,
 	etag TEXT,
 	content_type TEXT,
+	content_digest TEXT,
 	size BIGINT,
 	last_modified TIMESTAMP,
 	fetched_at TIMESTAMP,
@@ -359,6 +361,7 @@ var migrations = []migration{
 	{"003_ensure_artifacts_table", migrateEnsureArtifactsTable},
 	{"004_ensure_vulnerabilities_table", migrateEnsureVulnerabilitiesTable},
 	{"005_ensure_metadata_cache_table", migrateEnsureMetadataCacheTable},
+	{"006_add_metadata_content_digest", migrateAddMetadataContentDigest},
 }
 
 // isTableNotFound returns true if the error indicates a missing table.
@@ -581,6 +584,20 @@ func migrateEnsureMetadataCacheTable(db *DB) error {
 	return db.EnsureMetadataCacheTable()
 }
 
+func migrateAddMetadataContentDigest(db *DB) error {
+	hasColumn, err := db.HasColumn("metadata_cache", "content_digest")
+	if err != nil {
+		return fmt.Errorf("checking metadata_cache content_digest column: %w", err)
+	}
+	if hasColumn {
+		return nil
+	}
+	if _, err := db.Exec("ALTER TABLE metadata_cache ADD COLUMN content_digest TEXT"); err != nil {
+		return fmt.Errorf("adding metadata_cache content_digest column: %w", err)
+	}
+	return nil
+}
+
 // EnsureMetadataCacheTable creates the metadata_cache table if it doesn't exist.
 func (db *DB) EnsureMetadataCacheTable() error {
 	has, err := db.HasTable("metadata_cache")
@@ -601,6 +618,7 @@ func (db *DB) EnsureMetadataCacheTable() error {
 				storage_path TEXT NOT NULL,
 				etag TEXT,
 				content_type TEXT,
+				content_digest TEXT,
 				size BIGINT,
 				last_modified TIMESTAMP,
 				fetched_at TIMESTAMP,
@@ -618,6 +636,7 @@ func (db *DB) EnsureMetadataCacheTable() error {
 				storage_path TEXT NOT NULL,
 				etag TEXT,
 				content_type TEXT,
+				content_digest TEXT,
 				size INTEGER,
 				last_modified DATETIME,
 				fetched_at DATETIME,

internal/database/types.go

@@ -78,17 +78,18 @@ func (a *Artifact) IsCached() bool {
 
 // MetadataCacheEntry represents a cached metadata blob for offline serving.
 type MetadataCacheEntry struct {
-	ID           int64          `db:"id" json:"id"`
+	ID            int64          `db:"id" json:"id"`
-	Ecosystem    string         `db:"ecosystem" json:"ecosystem"`
+	Ecosystem     string         `db:"ecosystem" json:"ecosystem"`
-	Name         string         `db:"name" json:"name"`
+	Name          string         `db:"name" json:"name"`
-	StoragePath  string         `db:"storage_path" json:"storage_path"`
+	StoragePath   string         `db:"storage_path" json:"storage_path"`
-	ETag         sql.NullString `db:"etag" json:"etag,omitempty"`
+	ETag          sql.NullString `db:"etag" json:"etag,omitempty"`
-	ContentType  sql.NullString `db:"content_type" json:"content_type,omitempty"`
+	ContentType   sql.NullString `db:"content_type" json:"content_type,omitempty"`
-	Size         sql.NullInt64  `db:"size" json:"size,omitempty"`
+	ContentDigest sql.NullString `db:"content_digest" json:"content_digest,omitempty"`
-	LastModified sql.NullTime   `db:"last_modified" json:"last_modified,omitempty"`
+	Size          sql.NullInt64  `db:"size" json:"size,omitempty"`
-	FetchedAt    sql.NullTime   `db:"fetched_at" json:"fetched_at,omitempty"`
+	LastModified  sql.NullTime   `db:"last_modified" json:"last_modified,omitempty"`
-	CreatedAt    time.Time      `db:"created_at" json:"created_at"`
+	FetchedAt     sql.NullTime   `db:"fetched_at" json:"fetched_at,omitempty"`
-	UpdatedAt    time.Time      `db:"updated_at" json:"updated_at"`
+	CreatedAt     time.Time      `db:"created_at" json:"created_at"`
+	UpdatedAt     time.Time      `db:"updated_at" json:"updated_at"`
 }
 
 // Vulnerability represents a cached vulnerability record.

internal/handler/cargo.go

@@ -6,9 +6,10 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
-	"net/url"
 	"strings"
 	"time"
+
+	"github.com/git-pkgs/purl"
 )
 
 const (
@@ -29,18 +30,11 @@ type CargoHandler struct {
 }
 
 // NewCargoHandler creates a new cargo protocol handler.
-func NewCargoHandler(proxy *Proxy, proxyURL, indexURL, downloadURL string) *CargoHandler {
+func NewCargoHandler(proxy *Proxy, proxyURL string) *CargoHandler {
-	if strings.TrimSpace(indexURL) == "" {
-		indexURL = cargoUpstream
-	}
-	if strings.TrimSpace(downloadURL) == "" {
-		downloadURL = cargoDownloadBase
-	}
-
 	return &CargoHandler{
 		proxy:       proxy,
-		indexURL:    strings.TrimSuffix(indexURL, "/"),
+		indexURL:    cargoUpstream,
-		downloadURL: strings.TrimSuffix(downloadURL, "/"),
+		downloadURL: cargoDownloadBase,
 		proxyURL:    strings.TrimSuffix(proxyURL, "/"),
 	}
 }
@@ -149,7 +143,7 @@ func (h *CargoHandler) applyCooldownFiltering(downstreamResponse http.ResponseWr
 			continue
 		}
 
-		cratePURL := canonicalPackagePURL("cargo", crate.Name)
+		cratePURL := purl.MakePURLString("cargo", crate.Name, "")
 
 		if !h.proxy.Cooldown.IsAllowed("cargo", cratePURL, publishedAt) {
 			h.proxy.Logger.Info("cooldown: filtering cargo version",
@@ -197,17 +191,10 @@ func (h *CargoHandler) handleDownload(w http.ResponseWriter, r *http.Request) {
 	h.proxy.Logger.Info("cargo download request",
 		"crate", name, "version", version, "filename", filename)
 
-	downloadURL := fmt.Sprintf(
+	result, err := h.proxy.GetOrFetchArtifact(r.Context(), "cargo", name, version, filename)
-		"%s/%s/%s",
-		h.downloadURL,
-		url.PathEscape(name),
-		url.PathEscape(filename),
-	)
-	result, err := h.proxy.GetOrFetchArtifactFromURL(
-		r.Context(), "cargo", name, version, filename, downloadURL,
-	)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch crate")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch crate", http.StatusBadGateway)
 		return
 	}
 

internal/handler/cargo_test.go

@@ -2,7 +2,6 @@ package handler
 
 import (
 	"encoding/json"
-	"io"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
@@ -11,7 +10,6 @@ import (
 	"time"
 
 	"github.com/git-pkgs/cooldown"
-	"github.com/git-pkgs/registries/fetch"
 )
 
 func cargoTestProxy() *Proxy {
@@ -72,75 +70,6 @@ func TestCargoConfigEndpoint(t *testing.T) {
 	}
 }
 
-func TestCargoHandlerUsesConfiguredUpstreams(t *testing.T) {
-	t.Run("index", func(t *testing.T) {
-		var requestPath, authHeader string
-		upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			requestPath = r.URL.Path
-			authHeader = r.Header.Get("Authorization")
-			if authHeader != "Bearer cargo-token" {
-				w.WriteHeader(http.StatusUnauthorized)
-				return
-			}
-			w.Header().Set("Content-Type", "text/plain")
-			_, _ = io.WriteString(w, `{"name":"serde","vers":"1.0.0"}`)
-		}))
-		defer upstream.Close()
-
-		proxy, _, _, _ := setupTestProxy(t)
-		proxy.HTTPClient = upstream.Client()
-		proxy.AuthForURL = func(string) (string, string) {
-			return "Authorization", "Bearer cargo-token"
-		}
-		h := NewCargoHandler(
-			proxy,
-			"http://proxy.test",
-			upstream.URL+"/index/",
-			"https://crates.example.test/files/",
-		)
-
-		req := httptest.NewRequest(http.MethodGet, "/se/rd/serde", nil)
-		w := httptest.NewRecorder()
-		h.Routes().ServeHTTP(w, req)
-
-		if w.Code != http.StatusOK {
-			t.Fatalf("status = %d, want %d; body: %s", w.Code, http.StatusOK, w.Body.String())
-		}
-		if requestPath != "/index/se/rd/serde" {
-			t.Errorf("upstream path = %q, want %q", requestPath, "/index/se/rd/serde")
-		}
-		if authHeader != "Bearer cargo-token" {
-			t.Errorf("Authorization = %q, want %q", authHeader, "Bearer cargo-token")
-		}
-	})
-
-	t.Run("download", func(t *testing.T) {
-		proxy, _, _, artifactFetcher := setupTestProxy(t)
-		artifactFetcher.artifact = &fetch.Artifact{
-			Body:        io.NopCloser(strings.NewReader("crate")),
-			ContentType: "application/gzip",
-		}
-		h := NewCargoHandler(
-			proxy,
-			"http://proxy.test",
-			"https://index.example.test/root/",
-			"https://crates.example.test/files/",
-		)
-
-		req := httptest.NewRequest(http.MethodGet, "/crates/serde/1.0.0/download", nil)
-		w := httptest.NewRecorder()
-		h.Routes().ServeHTTP(w, req)
-
-		if w.Code != http.StatusOK {
-			t.Fatalf("status = %d, want %d; body: %s", w.Code, http.StatusOK, w.Body.String())
-		}
-		want := "https://crates.example.test/files/serde/serde-1.0.0.crate"
-		if artifactFetcher.fetchedURL != want {
-			t.Errorf("fetched URL = %q, want %q", artifactFetcher.fetchedURL, want)
-		}
-	})
-}
-
 func TestCargoIndexProxy(t *testing.T) {
 	// Create a mock upstream index server
 	indexContent := `{"name":"serde","vers":"1.0.0","deps":[],"cksum":"abc123"}

internal/handler/composer.go

@@ -10,6 +10,8 @@ import (
 	"path"
 	"strings"
 	"time"
+
+	"github.com/git-pkgs/purl"
 )
 
 const (
@@ -214,7 +216,7 @@ func deepCopyValue(v any) any {
 // filterAndRewriteVersions applies cooldown filtering and rewrites dist URLs
 // for a single package's version list.
 func (h *ComposerHandler) filterAndRewriteVersions(packageName string, versionList []any) []any {
-	packagePURL := canonicalPackagePURL("composer", packageName)
+	packagePURL := purl.MakePURLString("composer", packageName, "")
 
 	filtered := versionList[:0]
 	for _, v := range versionList {
@@ -346,7 +348,8 @@ func (h *ComposerHandler) handleDownload(w http.ResponseWriter, r *http.Request)
 
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "composer", packageName, version, filename, downloadURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch package")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
 		return
 	}
 

internal/handler/conan.go

@@ -84,7 +84,8 @@ func (h *ConanHandler) handleRecipeFile(w http.ResponseWriter, r *http.Request)
 
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "conan", packageName, storageVersion, storageFilename, upstreamURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch file")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch file", http.StatusBadGateway)
 		return
 	}
 
@@ -121,7 +122,8 @@ func (h *ConanHandler) handlePackageFile(w http.ResponseWriter, r *http.Request)
 
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "conan", packageName, storageVersion, storageFilename, upstreamURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch file")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch file", http.StatusBadGateway)
 		return
 	}
 

internal/handler/conda.go

@@ -6,6 +6,8 @@ import (
 	"net/http"
 	"strings"
 	"time"
+
+	"github.com/git-pkgs/purl"
 )
 
 const (
@@ -72,7 +74,8 @@ func (h *CondaHandler) handleDownload(w http.ResponseWriter, r *http.Request) {
 
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "conda", packageName, version, filename, upstreamURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch package")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
 		return
 	}
 
@@ -215,7 +218,7 @@ func (h *CondaHandler) applyCooldownFiltering(body []byte) ([]byte, error) {
 				continue
 			}
 
-			packagePURL := canonicalPackagePURL("conda", name)
+			packagePURL := purl.MakePURLString("conda", name, "")
 
 			if !h.proxy.Cooldown.IsAllowed("conda", packagePURL, publishedAt) {
 				version, _ := entryMap["version"].(string)

internal/handler/container.go

@@ -2,7 +2,6 @@ package handler
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -12,7 +11,6 @@ import (
 
 const (
 	dockerHubRegistry  = "https://registry-1.docker.io"
-	dockerHubAuth      = "https://auth.docker.io"
 	blobMatchCount     = 3 // full match + name + digest
 	manifestMatchCount = 3 // full match + name + reference
 	tagsListMatchCount = 2 // full match + name
@@ -24,7 +22,6 @@ const (
 type ContainerHandler struct {
 	proxy       *Proxy
 	registryURL string
-	authURL     string
 	proxyURL    string
 }
 
@@ -33,7 +30,6 @@ func NewContainerHandler(proxy *Proxy, proxyURL string) *ContainerHandler {
 	return &ContainerHandler{
 		proxy:       proxy,
 		registryURL: dockerHubRegistry,
-		authURL:     dockerHubAuth,
 		proxyURL:    strings.TrimSuffix(proxyURL, "/"),
 	}
 }
@@ -90,40 +86,43 @@ func (h *ContainerHandler) handleBlobDownload(w http.ResponseWriter, r *http.Req
 
 	h.proxy.Logger.Info("container blob request", "name", name, "digest", digest)
 
-	// Get auth token for upstream
+	filename := digest
-	token, err := h.getAuthToken(r.Context(), name, "pull")
+	cached, err := h.proxy.GetCachedArtifact(r.Context(), "oci", name, digest, filename)
 	if err != nil {
-		h.proxy.Logger.Error("failed to get auth token", "error", err)
+		h.proxy.Logger.Error("failed to check blob cache", "error", err)
-		h.containerError(w, http.StatusUnauthorized, "UNAUTHORIZED", "failed to authenticate")
+		h.containerError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "failed to check blob cache")
+		return
+	}
+	if cached != nil {
+		w.Header().Set("Docker-Content-Digest", digest)
+		w.Header().Set("Content-Type", "application/octet-stream")
+		if r.Method == http.MethodHead {
+			serveArtifactHead(w, cached)
+			return
+		}
+		ServeArtifact(w, cached)
 		return
 	}
 
 	// For HEAD requests, just proxy to upstream
 	if r.Method == http.MethodHead {
-		h.proxyBlobHead(w, r, name, digest, token)
+		h.proxyBlobHead(w, r, name, digest)
 		return
 	}
 
-	// Try to get from cache, or fetch from upstream with auth
+	// Try to get from cache, or fetch from the authentication-aware upstream client.
-	filename := digest
+	result, err := h.proxy.GetOrFetchArtifactFromURL(
-	headers := http.Header{"Authorization": {"Bearer " + token}}
-	result, err := h.proxy.GetOrFetchArtifactFromURLWithHeaders(
 		r.Context(),
 		"oci",
 		name,
 		digest, // use digest as version
 		filename,
 		fmt.Sprintf("%s/v2/%s/blobs/%s", h.registryURL, name, digest),
-		headers,
 	)
 
 	if err != nil {
-		if errors.Is(err, ErrUpstreamNotFound) {
-			h.containerError(w, http.StatusNotFound, "BLOB_UNKNOWN", "blob unknown to registry")
-			return
-		}
 		h.proxy.Logger.Error("failed to fetch blob", "error", err)
-		h.containerError(w, http.StatusBadGateway, "INTERNAL_ERROR", "failed to fetch blob")
+		h.containerError(w, http.StatusBadGateway, "BLOB_UNKNOWN", "failed to fetch blob")
 		return
 	}
 
@@ -132,8 +131,31 @@ func (h *ContainerHandler) handleBlobDownload(w http.ResponseWriter, r *http.Req
 	ServeArtifact(w, result)
 }
 
-// handleManifest proxies manifest requests to upstream.
+func serveArtifactHead(w http.ResponseWriter, result *CacheResult) {
-// Manifests change when tags are updated, so we proxy these directly.
+	if result.RedirectURL != "" {
+		if result.Hash != "" {
+			w.Header().Set("ETag", fmt.Sprintf(`"%s"`, result.Hash))
+		}
+		w.Header().Set("Location", result.RedirectURL)
+		w.WriteHeader(http.StatusFound)
+		return
+	}
+	if result.Reader != nil {
+		_ = result.Reader.Close()
+	}
+	if result.ContentType != "" {
+		w.Header().Set("Content-Type", result.ContentType)
+	}
+	if result.Size >= 0 {
+		w.Header().Set("Content-Length", fmt.Sprintf("%d", result.Size))
+	}
+	if result.Hash != "" {
+		w.Header().Set("ETag", fmt.Sprintf(`"%s"`, result.Hash))
+	}
+	w.WriteHeader(http.StatusOK)
+}
+
+// handleManifest serves immutable manifests from cache and revalidates mutable tags.
 // Path format: {name}/manifests/{reference}
 func (h *ContainerHandler) handleManifest(w http.ResponseWriter, r *http.Request, path string) {
 	if r.Method != http.MethodGet && r.Method != http.MethodHead {
@@ -148,57 +170,7 @@ func (h *ContainerHandler) handleManifest(w http.ResponseWriter, r *http.Request
 	}
 
 	h.proxy.Logger.Info("container manifest request", "name", name, "reference", reference)
-
+	h.serveManifest(w, r, name, reference)
-	// Get auth token
-	token, err := h.getAuthToken(r.Context(), name, "pull")
-	if err != nil {
-		h.proxy.Logger.Error("failed to get auth token", "error", err)
-		h.containerError(w, http.StatusUnauthorized, "UNAUTHORIZED", "failed to authenticate")
-		return
-	}
-
-	// Proxy to upstream
-	upstreamURL := fmt.Sprintf("%s/v2/%s/manifests/%s", h.registryURL, name, reference)
-
-	req, err := http.NewRequestWithContext(r.Context(), r.Method, upstreamURL, nil)
-	if err != nil {
-		h.containerError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "failed to create request")
-		return
-	}
-
-	req.Header.Set("Authorization", "Bearer "+token)
-
-	// Forward Accept header for content negotiation
-	if accept := r.Header.Get("Accept"); accept != "" {
-		req.Header.Set("Accept", accept)
-	} else {
-		// Default accept headers for manifests
-		req.Header.Set("Accept", strings.Join([]string{
-			"application/vnd.oci.image.manifest.v1+json",
-			"application/vnd.oci.image.index.v1+json",
-			"application/vnd.docker.distribution.manifest.v2+json",
-			"application/vnd.docker.distribution.manifest.list.v2+json",
-			"application/vnd.docker.distribution.manifest.v1+prettyjws",
-		}, ", "))
-	}
-
-	resp, err := h.proxy.HTTPClient.Do(req)
-	if err != nil {
-		h.proxy.Logger.Error("failed to fetch manifest", "error", err)
-		h.containerError(w, http.StatusBadGateway, "INTERNAL_ERROR", "failed to fetch from upstream")
-		return
-	}
-	defer func() { _ = resp.Body.Close() }()
-
-	// Copy relevant headers
-	for _, header := range []string{"Content-Type", "Content-Length", "Docker-Content-Digest", "ETag"} {
-		if v := resp.Header.Get(header); v != "" {
-			w.Header().Set(header, v)
-		}
-	}
-
-	w.WriteHeader(resp.StatusCode)
-	_, _ = io.Copy(w, resp.Body)
 }
 
 // handleTagsList proxies tag list requests to upstream.
@@ -214,13 +186,6 @@ func (h *ContainerHandler) handleTagsList(w http.ResponseWriter, r *http.Request
 		return
 	}
 
-	// Get auth token
-	token, err := h.getAuthToken(r.Context(), name, "pull")
-	if err != nil {
-		h.containerError(w, http.StatusUnauthorized, "UNAUTHORIZED", "failed to authenticate")
-		return
-	}
-
 	upstreamURL := fmt.Sprintf("%s/v2/%s/tags/list", h.registryURL, name)
 	if r.URL.RawQuery != "" {
 		upstreamURL += "?" + r.URL.RawQuery
@@ -232,8 +197,6 @@ func (h *ContainerHandler) handleTagsList(w http.ResponseWriter, r *http.Request
 		return
 	}
 
-	req.Header.Set("Authorization", "Bearer "+token)
-
 	resp, err := h.proxy.HTTPClient.Do(req)
 	if err != nil {
 		h.containerError(w, http.StatusBadGateway, "INTERNAL_ERROR", "failed to fetch from upstream")
@@ -246,45 +209,8 @@ func (h *ContainerHandler) handleTagsList(w http.ResponseWriter, r *http.Request
 	_, _ = io.Copy(w, resp.Body)
 }
 
-// getAuthToken gets a bearer token for the specified repository.
-// Docker Hub requires auth even for public images.
-func (h *ContainerHandler) getAuthToken(_ interface{ Done() <-chan struct{} }, repository, action string) (string, error) {
-	// For Docker Hub: https://auth.docker.io/token?service=registry.docker.io&scope=repository:{repo}:pull
-	authURL := fmt.Sprintf("%s/token?service=registry.docker.io&scope=repository:%s:%s",
-		h.authURL, repository, action)
-
-	req, err := http.NewRequest(http.MethodGet, authURL, nil)
-	if err != nil {
-		return "", err
-	}
-
-	resp, err := h.proxy.HTTPClient.Do(req)
-	if err != nil {
-		return "", err
-	}
-	defer func() { _ = resp.Body.Close() }()
-
-	if resp.StatusCode != http.StatusOK {
-		return "", fmt.Errorf("auth failed with status %d", resp.StatusCode)
-	}
-
-	var tokenResp struct {
-		Token       string `json:"token"`
-		AccessToken string `json:"access_token"`
-	}
-
-	if err := json.NewDecoder(resp.Body).Decode(&tokenResp); err != nil {
-		return "", err
-	}
-
-	if tokenResp.Token != "" {
-		return tokenResp.Token, nil
-	}
-	return tokenResp.AccessToken, nil
-}
-
 // proxyBlobHead handles HEAD requests for blobs.
-func (h *ContainerHandler) proxyBlobHead(w http.ResponseWriter, r *http.Request, name, digest, token string) {
+func (h *ContainerHandler) proxyBlobHead(w http.ResponseWriter, r *http.Request, name, digest string) {
 	upstreamURL := fmt.Sprintf("%s/v2/%s/blobs/%s", h.registryURL, name, digest)
 
 	req, err := http.NewRequestWithContext(r.Context(), http.MethodHead, upstreamURL, nil)
@@ -293,8 +219,6 @@ func (h *ContainerHandler) proxyBlobHead(w http.ResponseWriter, r *http.Request,
 		return
 	}
 
-	req.Header.Set("Authorization", "Bearer "+token)
-
 	resp, err := h.proxy.HTTPClient.Do(req)
 	if err != nil {
 		h.containerError(w, http.StatusBadGateway, "INTERNAL_ERROR", "failed to fetch from upstream")

internal/handler/container_manifest.go

@@ -0,0 +1,251 @@
+package handler
+
+import (
+	"bytes"
+	"context"
+	"crypto/sha256"
+	"database/sql"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"net/http"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/git-pkgs/proxy/internal/database"
+)
+
+const (
+	containerManifestCacheEcosystem = "oci-manifest"
+	containerStaleWarning           = `110 - "Response is Stale"`
+)
+
+var manifestDigestReferencePattern = regexp.MustCompile(`^[a-z0-9]+:[a-f0-9]+$`)
+
+type cachedContainerManifest struct {
+	body          []byte
+	contentType   string
+	contentDigest string
+	etag          string
+	size          int64
+	fetchedAt     time.Time
+}
+
+func (h *ContainerHandler) serveManifest(w http.ResponseWriter, r *http.Request, name, reference string) {
+	accept := containerManifestAccept(r)
+	cacheKey := h.containerManifestCacheKey(name, reference, accept)
+	cached, err := h.loadContainerManifest(r.Context(), cacheKey)
+	if err != nil {
+		h.proxy.Logger.Warn("failed to read cached container manifest", "error", err)
+		cached = nil
+	}
+
+	immutable := manifestDigestReferencePattern.MatchString(reference)
+	if cached != nil && (immutable || h.containerManifestFresh(cached)) {
+		writeContainerManifest(w, r.Method, cached, false)
+		return
+	}
+
+	upstreamURL := fmt.Sprintf("%s/v2/%s/manifests/%s", h.registryURL, name, reference)
+	req, err := http.NewRequestWithContext(r.Context(), r.Method, upstreamURL, nil)
+	if err != nil {
+		h.containerError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "failed to create request")
+		return
+	}
+	req.Header.Set("Accept", accept)
+	if cached != nil && cached.etag != "" {
+		req.Header.Set("If-None-Match", cached.etag)
+	}
+
+	resp, err := h.proxy.HTTPClient.Do(req)
+	if err != nil {
+		h.serveStaleManifestOrError(w, r, cached, err)
+		return
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode == http.StatusNotModified && cached != nil {
+		cached.fetchedAt = time.Now()
+		if err := h.storeContainerManifest(r.Context(), cacheKey, cached); err != nil {
+			h.proxy.Logger.Warn("failed to refresh cached container manifest", "error", err)
+		}
+		writeContainerManifest(w, r.Method, cached, false)
+		return
+	}
+	if resp.StatusCode != http.StatusOK {
+		if cached != nil && shouldServeStaleManifest(resp.StatusCode) {
+			writeContainerManifest(w, r.Method, cached, true)
+			return
+		}
+		copyContainerManifestHeaders(w.Header(), resp.Header)
+		w.WriteHeader(resp.StatusCode)
+		_, _ = io.Copy(w, resp.Body)
+		return
+	}
+
+	if r.Method == http.MethodHead {
+		copyContainerManifestHeaders(w.Header(), resp.Header)
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+
+	body, err := h.proxy.ReadMetadata(resp.Body)
+	if err != nil {
+		h.serveStaleManifestOrError(w, r, cached, fmt.Errorf("reading manifest: %w", err))
+		return
+	}
+	manifest := &cachedContainerManifest{
+		body:          body,
+		contentType:   resp.Header.Get("Content-Type"),
+		contentDigest: resp.Header.Get("Docker-Content-Digest"),
+		etag:          resp.Header.Get("ETag"),
+		size:          int64(len(body)),
+		fetchedAt:     time.Now(),
+	}
+	if manifest.contentDigest == "" {
+		manifest.contentDigest = sha256Digest(body)
+	}
+	if err := h.storeContainerManifest(r.Context(), cacheKey, manifest); err != nil {
+		h.proxy.Logger.Warn("failed to cache container manifest", "error", err)
+	}
+	if manifest.contentDigest != reference && manifestDigestReferencePattern.MatchString(manifest.contentDigest) {
+		digestKey := h.containerManifestCacheKey(name, manifest.contentDigest, accept)
+		if err := h.storeContainerManifest(r.Context(), digestKey, manifest); err != nil {
+			h.proxy.Logger.Warn("failed to cache container manifest by digest", "error", err)
+		}
+	}
+	writeContainerManifest(w, r.Method, manifest, false)
+}
+
+func (h *ContainerHandler) serveStaleManifestOrError(w http.ResponseWriter, r *http.Request, cached *cachedContainerManifest, err error) {
+	if cached != nil {
+		h.proxy.Logger.Warn("upstream manifest fetch failed, serving stale cache", "error", err)
+		writeContainerManifest(w, r.Method, cached, true)
+		return
+	}
+	h.proxy.Logger.Error("failed to fetch manifest", "error", err)
+	h.containerError(w, http.StatusBadGateway, "INTERNAL_ERROR", "failed to fetch from upstream")
+}
+
+func (h *ContainerHandler) containerManifestFresh(manifest *cachedContainerManifest) bool {
+	return h.proxy.MetadataTTL > 0 && !manifest.fetchedAt.IsZero() && time.Since(manifest.fetchedAt) < h.proxy.MetadataTTL
+}
+
+func (h *ContainerHandler) containerManifestCacheKey(name, reference, accept string) string {
+	identity := strings.Join([]string{h.registryURL, name, reference, accept}, "\x00")
+	sum := sha256.Sum256([]byte(identity))
+	return hex.EncodeToString(sum[:])
+}
+
+func (h *ContainerHandler) loadContainerManifest(ctx context.Context, cacheKey string) (*cachedContainerManifest, error) {
+	if h.proxy.DB == nil || h.proxy.Storage == nil {
+		return nil, nil
+	}
+	entry, err := h.proxy.DB.GetMetadataCache(containerManifestCacheEcosystem, cacheKey)
+	if err != nil || entry == nil {
+		return nil, err
+	}
+	reader, err := h.proxy.Storage.Open(ctx, entry.StoragePath)
+	if err != nil {
+		return nil, nil
+	}
+	defer func() { _ = reader.Close() }()
+	body, err := h.proxy.ReadMetadata(reader)
+	if err != nil {
+		return nil, err
+	}
+
+	manifest := &cachedContainerManifest{body: body, size: int64(len(body))}
+	if entry.ContentType.Valid {
+		manifest.contentType = entry.ContentType.String
+	}
+	if entry.ContentDigest.Valid {
+		manifest.contentDigest = entry.ContentDigest.String
+	} else {
+		manifest.contentDigest = sha256Digest(body)
+	}
+	if entry.ETag.Valid {
+		manifest.etag = entry.ETag.String
+	}
+	if entry.Size.Valid {
+		manifest.size = entry.Size.Int64
+	}
+	if entry.FetchedAt.Valid {
+		manifest.fetchedAt = entry.FetchedAt.Time
+	}
+	return manifest, nil
+}
+
+func (h *ContainerHandler) storeContainerManifest(ctx context.Context, cacheKey string, manifest *cachedContainerManifest) error {
+	if h.proxy.DB == nil || h.proxy.Storage == nil {
+		return nil
+	}
+	storagePath := metadataStoragePath(containerManifestCacheEcosystem, cacheKey)
+	size, _, err := h.proxy.Storage.Store(ctx, storagePath, bytes.NewReader(manifest.body))
+	if err != nil {
+		return fmt.Errorf("storing manifest: %w", err)
+	}
+	manifest.size = size
+	return h.proxy.DB.UpsertMetadataCache(&database.MetadataCacheEntry{
+		Ecosystem:     containerManifestCacheEcosystem,
+		Name:          cacheKey,
+		StoragePath:   storagePath,
+		ETag:          sql.NullString{String: manifest.etag, Valid: manifest.etag != ""},
+		ContentType:   sql.NullString{String: manifest.contentType, Valid: manifest.contentType != ""},
+		ContentDigest: sql.NullString{String: manifest.contentDigest, Valid: manifest.contentDigest != ""},
+		Size:          sql.NullInt64{Int64: size, Valid: true},
+		FetchedAt:     sql.NullTime{Time: manifest.fetchedAt, Valid: !manifest.fetchedAt.IsZero()},
+	})
+}
+
+func writeContainerManifest(w http.ResponseWriter, method string, manifest *cachedContainerManifest, stale bool) {
+	if manifest.contentType != "" {
+		w.Header().Set("Content-Type", manifest.contentType)
+	}
+	w.Header().Set("Content-Length", strconv.FormatInt(manifest.size, 10))
+	if manifest.contentDigest != "" {
+		w.Header().Set("Docker-Content-Digest", manifest.contentDigest)
+	}
+	if manifest.etag != "" {
+		w.Header().Set("ETag", manifest.etag)
+	}
+	if stale {
+		w.Header().Set("Warning", containerStaleWarning)
+	}
+	w.WriteHeader(http.StatusOK)
+	if method != http.MethodHead {
+		_, _ = w.Write(manifest.body)
+	}
+}
+
+func containerManifestAccept(r *http.Request) string {
+	if accept := r.Header.Get("Accept"); accept != "" {
+		return accept
+	}
+	return strings.Join([]string{
+		"application/vnd.oci.image.manifest.v1+json",
+		"application/vnd.oci.image.index.v1+json",
+		"application/vnd.docker.distribution.manifest.v2+json",
+		"application/vnd.docker.distribution.manifest.list.v2+json",
+		"application/vnd.docker.distribution.manifest.v1+prettyjws",
+	}, ", ")
+}
+
+func copyContainerManifestHeaders(destination, source http.Header) {
+	for _, header := range []string{"Content-Type", "Content-Length", "Docker-Content-Digest", "ETag", "WWW-Authenticate"} {
+		if value := source.Get(header); value != "" {
+			destination.Set(header, value)
+		}
+	}
+}
+
+func shouldServeStaleManifest(status int) bool {
+	return status == http.StatusTooManyRequests || status >= http.StatusInternalServerError
+}
+
+func sha256Digest(body []byte) string {
+	digest := sha256.Sum256(body)
+	return "sha256:" + hex.EncodeToString(digest[:])
+}

internal/handler/container_test.go

@@ -1,16 +1,14 @@
 package handler
 
 import (
-	"bytes"
-	"context"
 	"encoding/json"
 	"io"
-	"log/slog"
 	"net/http"
 	"net/http/httptest"
+	"strconv"
 	"testing"
 
-	"github.com/git-pkgs/proxy/internal/database"
+	upstreamhttp "github.com/git-pkgs/proxy/internal/httpclient"
 	"github.com/git-pkgs/registries/fetch"
 )
 
@@ -135,90 +133,387 @@ func TestContainerHandler_parseTagsListPath(t *testing.T) {
 	}
 }
 
-func TestContainerHandler_BlobDownload_CachesWithAuth(t *testing.T) {
+func TestContainerHandler_BlobDownload_DiscoversBearerChallenge(t *testing.T) {
-	// Set up a mock auth server that returns a token
+	digest := "sha256:abc123def456abc123def456abc123def456abc123def456abc123def456abcd"
-	authServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	registryRequests := 0
-		w.Header().Set("Content-Type", "application/json")
+	tokenRequests := 0
-		_ = json.NewEncoder(w).Encode(map[string]string{"token": "test-token-123"})
+	var upstream *httptest.Server
+	upstream = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.URL.Path {
+		case "/token":
+			tokenRequests++
+			w.Header().Set("Content-Type", "application/json")
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"token":      "discovered-token",
+				"expires_in": 3600,
+			})
+		case "/v2/library/nginx/blobs/" + digest:
+			registryRequests++
+			if r.Header.Get("Authorization") != "Bearer discovered-token" {
+				w.Header().Set("WWW-Authenticate", `Bearer realm="`+upstream.URL+`/token",service="registry.test",scope="repository:library/nginx:pull"`)
+				http.Error(w, "authentication required", http.StatusUnauthorized)
+				return
+			}
+			w.Header().Set("Content-Type", "application/octet-stream")
+			_, _ = io.WriteString(w, "upstream blob")
+		default:
+			http.NotFound(w, r)
+		}
 	}))
-	defer authServer.Close()
+	defer upstream.Close()
 
-	// Set up mock fetcher that captures headers
+	proxy, _, _, _ := setupTestProxy(t)
-	var capturedHeaders http.Header
+	authTransport := upstreamhttp.NewTransport(http.DefaultTransport, nil)
-	mf := &mockFetcherWithHeaders{
+	client := &http.Client{Transport: authTransport}
-		fetchFn: func(_ context.Context, _ string, headers http.Header) (*fetch.Artifact, error) {
+	artifactFetcher := fetch.NewFetcher(
-			capturedHeaders = headers
+		fetch.WithHTTPClient(client),
-			return &fetch.Artifact{
+		fetch.WithMaxRetries(0),
-				Body:        io.NopCloser(bytes.NewReader([]byte("blob-content"))),
+	)
-				Size:        12,
+	t.Cleanup(func() { _ = artifactFetcher.Close() })
-				ContentType: "application/octet-stream",
+	proxy.Fetcher = artifactFetcher
-			}, nil
+	proxy.HTTPClient = client
-		},
-	}
-
-	dir := t.TempDir()
-	db, err := database.Create(dir + "/test.db")
-	if err != nil {
-		t.Fatalf("failed to create test database: %v", err)
-	}
-	t.Cleanup(func() { _ = db.Close() })
-
-	store := newMockStorage()
-	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
-	proxy := &Proxy{
-		DB:         db,
-		Storage:    store,
-		Fetcher:    mf,
-		Logger:     logger,
-		HTTPClient: &http.Client{},
-	}
 
 	h := &ContainerHandler{
 		proxy:       proxy,
-		registryURL: "https://registry-1.docker.io",
+		registryURL: upstream.URL,
-		authURL:     authServer.URL,
 		proxyURL:    "http://localhost:8080",
 	}
 
-	handler := h.Routes()
+	for range 2 {
-	req := httptest.NewRequest(http.MethodGet, "/library/nginx/blobs/sha256:abc123def456abc123def456abc123def456abc123def456abc123def456abcd", nil)
+		req := httptest.NewRequest(http.MethodGet, "/library/nginx/blobs/"+digest, nil)
+		w := httptest.NewRecorder()
+		h.Routes().ServeHTTP(w, req)
+		if w.Code != http.StatusOK {
+			t.Fatalf("status = %d, want %d; body: %s", w.Code, http.StatusOK, w.Body.String())
+		}
+		if got := w.Body.String(); got != "upstream blob" {
+			t.Errorf("body = %q, want %q", got, "upstream blob")
+		}
+	}
+
+	if tokenRequests != 1 {
+		t.Errorf("token requests = %d, want 1", tokenRequests)
+	}
+	if registryRequests != 2 {
+		t.Errorf("registry requests = %d, want 2", registryRequests)
+	}
+}
+
+func TestContainerHandler_BlobDownload_CacheHitSkipsAuth(t *testing.T) {
+	proxy, db, store, fetcher := setupTestProxy(t)
+	digest := "sha256:abc123def456abc123def456abc123def456abc123def456abc123def456abcd"
+	seedPackage(t, db, store, "oci", "library/nginx", digest, digest, "cached blob")
+
+	upstreamRequests := 0
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		upstreamRequests++
+		http.Error(w, "upstream unavailable", http.StatusServiceUnavailable)
+	}))
+	defer upstream.Close()
+
+	h := &ContainerHandler{
+		proxy:       proxy,
+		registryURL: upstream.URL,
+		proxyURL:    "http://localhost:8080",
+	}
+
+	req := httptest.NewRequest(http.MethodGet, "/library/nginx/blobs/"+digest, nil)
 	w := httptest.NewRecorder()
-	handler.ServeHTTP(w, req)
+	h.Routes().ServeHTTP(w, req)
 
 	if w.Code != http.StatusOK {
-		t.Errorf("got status %d, want %d; body: %s", w.Code, http.StatusOK, w.Body.String())
+		t.Fatalf("status = %d, want %d; body: %s", w.Code, http.StatusOK, w.Body.String())
 	}
-
+	if got := w.Body.String(); got != "cached blob" {
-	// Verify auth header was passed to the fetcher
+		t.Errorf("body = %q, want %q", got, "cached blob")
-	if capturedHeaders == nil {
-		t.Fatal("expected headers to be passed to fetcher, got nil")
 	}
-	auth := capturedHeaders.Get("Authorization")
+	if upstreamRequests != 0 {
-	if auth != "Bearer test-token-123" {
+		t.Errorf("upstream requests = %d, want 0", upstreamRequests)
-		t.Errorf("Authorization = %q, want %q", auth, "Bearer test-token-123")
 	}
-
+	if fetcher.fetchCalled {
-	// Verify response headers
+		t.Error("fetcher should not be called on cache hit")
-	if got := w.Header().Get("Docker-Content-Digest"); got != "sha256:abc123def456abc123def456abc123def456abc123def456abc123def456abcd" {
-		t.Errorf("Docker-Content-Digest = %q, want digest", got)
 	}
 }
 
-// mockFetcherWithHeaders captures headers passed to FetchWithHeaders.
+func TestContainerHandler_BlobHead_CacheHitSkipsUpstreamAndAuth(t *testing.T) {
-type mockFetcherWithHeaders struct {
+	proxy, db, store, fetcher := setupTestProxy(t)
-	fetchFn func(ctx context.Context, url string, headers http.Header) (*fetch.Artifact, error)
+	digest := "sha256:abc123def456abc123def456abc123def456abc123def456abc123def456abcd"
+	seedPackage(t, db, store, "oci", "library/nginx", digest, digest, "cached blob")
+
+	upstreamRequests := 0
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		upstreamRequests++
+		http.Error(w, "upstream unavailable", http.StatusServiceUnavailable)
+	}))
+	defer upstream.Close()
+	proxy.HTTPClient = upstream.Client()
+
+	h := &ContainerHandler{
+		proxy:       proxy,
+		registryURL: upstream.URL,
+		proxyURL:    "http://localhost:8080",
+	}
+
+	req := httptest.NewRequest(http.MethodHead, "/library/nginx/blobs/"+digest, nil)
+	w := httptest.NewRecorder()
+	h.Routes().ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d, want %d; body: %s", w.Code, http.StatusOK, w.Body.String())
+	}
+	if got := w.Header().Get("Docker-Content-Digest"); got != digest {
+		t.Errorf("Docker-Content-Digest = %q, want %q", got, digest)
+	}
+	if got := w.Header().Get("Content-Length"); got != "11" {
+		t.Errorf("Content-Length = %q, want %q", got, "11")
+	}
+	if w.Body.Len() != 0 {
+		t.Errorf("HEAD response body length = %d, want 0", w.Body.Len())
+	}
+	if upstreamRequests != 0 {
+		t.Errorf("upstream requests = %d, want 0", upstreamRequests)
+	}
+	if fetcher.fetchCalled {
+		t.Error("fetcher should not be called on cache hit")
+	}
 }
 
-func (f *mockFetcherWithHeaders) Fetch(ctx context.Context, url string) (*fetch.Artifact, error) {
+func TestContainerHandler_BlobHead_DirectServeRedirects(t *testing.T) {
-	return f.FetchWithHeaders(ctx, url, nil)
+	proxy, db, store, fetcher := setupTestProxy(t)
+	digest := "sha256:abc123def456abc123def456abc123def456abc123def456abc123def456abcd"
+	seedPackage(t, db, store, "oci", "library/nginx", digest, digest, "cached blob")
+	store.signedURL = "https://storage.example.test/cached-blob?signature=test"
+	proxy.DirectServe = true
+
+	h := &ContainerHandler{
+		proxy:       proxy,
+		registryURL: "https://registry.example.test",
+		proxyURL:    "http://localhost:8080",
+	}
+
+	req := httptest.NewRequest(http.MethodHead, "/library/nginx/blobs/"+digest, nil)
+	w := httptest.NewRecorder()
+	h.Routes().ServeHTTP(w, req)
+
+	if w.Code != http.StatusFound {
+		t.Fatalf("status = %d, want %d", w.Code, http.StatusFound)
+	}
+	if got := w.Header().Get("Location"); got != store.signedURL {
+		t.Errorf("Location = %q, want %q", got, store.signedURL)
+	}
+	if got := w.Header().Get("ETag"); got != `"abc123"` {
+		t.Errorf("ETag = %q, want %q", got, `"abc123"`)
+	}
+	if w.Body.Len() != 0 {
+		t.Errorf("HEAD response body length = %d, want 0", w.Body.Len())
+	}
+	if fetcher.fetchCalled {
+		t.Error("fetcher should not be called on cache hit")
+	}
 }
 
-func (f *mockFetcherWithHeaders) FetchWithHeaders(ctx context.Context, url string, headers http.Header) (*fetch.Artifact, error) {
+func TestContainerHandler_ManifestByDigest_CacheHitSkipsUpstream(t *testing.T) {
-	return f.fetchFn(ctx, url, headers)
+	digest := "sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+	manifest := `{"schemaVersion":2,"mediaType":"application/vnd.oci.image.manifest.v1+json"}`
+	upstreamAvailable := true
+	upstreamRequests := 0
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		upstreamRequests++
+		if !upstreamAvailable {
+			http.Error(w, "upstream unavailable", http.StatusServiceUnavailable)
+			return
+		}
+		if r.URL.Path != "/v2/library/nginx/manifests/"+digest {
+			http.NotFound(w, r)
+			return
+		}
+		w.Header().Set("Content-Type", "application/vnd.oci.image.manifest.v1+json")
+		w.Header().Set("Docker-Content-Digest", digest)
+		w.Header().Set("ETag", `"manifest-etag"`)
+		if r.Method != http.MethodHead {
+			_, _ = io.WriteString(w, manifest)
+		}
+	}))
+	defer upstream.Close()
+
+	proxy, _, _, _ := setupTestProxy(t)
+	proxy.HTTPClient = upstream.Client()
+	h := &ContainerHandler{proxy: proxy, registryURL: upstream.URL, proxyURL: "http://localhost:8080"}
+
+	first := httptest.NewRecorder()
+	h.Routes().ServeHTTP(first, httptest.NewRequest(http.MethodGet, "/library/nginx/manifests/"+digest, nil))
+	if first.Code != http.StatusOK {
+		t.Fatalf("initial status = %d, want %d; body: %s", first.Code, http.StatusOK, first.Body.String())
+	}
+	if first.Body.String() != manifest {
+		t.Fatalf("initial body = %q, want %q", first.Body.String(), manifest)
+	}
+
+	upstreamAvailable = false
+	second := httptest.NewRecorder()
+	h.Routes().ServeHTTP(second, httptest.NewRequest(http.MethodGet, "/library/nginx/manifests/"+digest, nil))
+	if second.Code != http.StatusOK {
+		t.Fatalf("cached status = %d, want %d; body: %s", second.Code, http.StatusOK, second.Body.String())
+	}
+	if second.Body.String() != manifest {
+		t.Errorf("cached body = %q, want %q", second.Body.String(), manifest)
+	}
+	if got := second.Header().Get("Docker-Content-Digest"); got != digest {
+		t.Errorf("cached Docker-Content-Digest = %q, want %q", got, digest)
+	}
+
+	head := httptest.NewRecorder()
+	h.Routes().ServeHTTP(head, httptest.NewRequest(http.MethodHead, "/library/nginx/manifests/"+digest, nil))
+	if head.Code != http.StatusOK {
+		t.Fatalf("cached HEAD status = %d, want %d", head.Code, http.StatusOK)
+	}
+	wantLength := strconv.Itoa(len(manifest))
+	if got := head.Header().Get("Content-Length"); got != wantLength {
+		t.Errorf("cached HEAD Content-Length = %q, want %q", got, wantLength)
+	}
+	if head.Body.Len() != 0 {
+		t.Errorf("cached HEAD body length = %d, want 0", head.Body.Len())
+	}
+	if upstreamRequests != 1 {
+		t.Errorf("upstream requests = %d, want 1", upstreamRequests)
+	}
 }
 
-func (f *mockFetcherWithHeaders) Head(_ context.Context, _ string) (int64, string, error) {
+func TestContainerHandler_ManifestByTag_UsesStaleCacheOnUpstreamFailure(t *testing.T) {
-	return 0, "", nil
+	digest := "sha256:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
+	manifest := `{"schemaVersion":2,"mediaType":"application/vnd.oci.image.index.v1+json"}`
+	upstreamAvailable := true
+	upstreamRequests := 0
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		upstreamRequests++
+		if !upstreamAvailable {
+			http.Error(w, "upstream unavailable", http.StatusServiceUnavailable)
+			return
+		}
+		w.Header().Set("Content-Type", "application/vnd.oci.image.index.v1+json")
+		w.Header().Set("Docker-Content-Digest", digest)
+		_, _ = io.WriteString(w, manifest)
+	}))
+	defer upstream.Close()
+
+	proxy, _, _, _ := setupTestProxy(t)
+	proxy.HTTPClient = upstream.Client()
+	proxy.MetadataTTL = 0
+	h := &ContainerHandler{proxy: proxy, registryURL: upstream.URL, proxyURL: "http://localhost:8080"}
+
+	first := httptest.NewRecorder()
+	h.Routes().ServeHTTP(first, httptest.NewRequest(http.MethodGet, "/library/nginx/manifests/latest", nil))
+	if first.Code != http.StatusOK {
+		t.Fatalf("initial status = %d, want %d; body: %s", first.Code, http.StatusOK, first.Body.String())
+	}
+
+	upstreamAvailable = false
+	second := httptest.NewRecorder()
+	h.Routes().ServeHTTP(second, httptest.NewRequest(http.MethodGet, "/library/nginx/manifests/latest", nil))
+	if second.Code != http.StatusOK {
+		t.Fatalf("stale status = %d, want %d; body: %s", second.Code, http.StatusOK, second.Body.String())
+	}
+	if second.Body.String() != manifest {
+		t.Errorf("stale body = %q, want %q", second.Body.String(), manifest)
+	}
+	if got := second.Header().Get("Warning"); got != `110 - "Response is Stale"` {
+		t.Errorf("Warning = %q, want stale warning", got)
+	}
+	if got := second.Header().Get("Docker-Content-Digest"); got != digest {
+		t.Errorf("stale Docker-Content-Digest = %q, want %q", got, digest)
+	}
+	if upstreamRequests != 2 {
+		t.Errorf("upstream requests = %d, want 2", upstreamRequests)
+	}
+}
+
+func TestContainerHandler_ManifestByTag_CachesDigestAlias(t *testing.T) {
+	digest := "sha256:cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc"
+	manifest := `{"schemaVersion":2,"mediaType":"application/vnd.oci.image.manifest.v1+json"}`
+	upstreamAvailable := true
+	upstreamRequests := 0
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		upstreamRequests++
+		if !upstreamAvailable {
+			http.Error(w, "upstream unavailable", http.StatusServiceUnavailable)
+			return
+		}
+		if r.URL.Path != "/v2/library/nginx/manifests/latest" {
+			http.NotFound(w, r)
+			return
+		}
+		w.Header().Set("Content-Type", "application/vnd.oci.image.manifest.v1+json")
+		w.Header().Set("Docker-Content-Digest", digest)
+		_, _ = io.WriteString(w, manifest)
+	}))
+	defer upstream.Close()
+
+	proxy, _, _, _ := setupTestProxy(t)
+	proxy.HTTPClient = upstream.Client()
+	h := &ContainerHandler{proxy: proxy, registryURL: upstream.URL, proxyURL: "http://localhost:8080"}
+
+	first := httptest.NewRecorder()
+	h.Routes().ServeHTTP(first, httptest.NewRequest(http.MethodGet, "/library/nginx/manifests/latest", nil))
+	if first.Code != http.StatusOK {
+		t.Fatalf("tag status = %d, want %d; body: %s", first.Code, http.StatusOK, first.Body.String())
+	}
+
+	upstreamAvailable = false
+	byDigest := httptest.NewRecorder()
+	h.Routes().ServeHTTP(byDigest, httptest.NewRequest(http.MethodGet, "/library/nginx/manifests/"+digest, nil))
+	if byDigest.Code != http.StatusOK {
+		t.Fatalf("digest status = %d, want %d; body: %s", byDigest.Code, http.StatusOK, byDigest.Body.String())
+	}
+	if byDigest.Body.String() != manifest {
+		t.Errorf("digest body = %q, want %q", byDigest.Body.String(), manifest)
+	}
+	if got := byDigest.Header().Get("Docker-Content-Digest"); got != digest {
+		t.Errorf("Docker-Content-Digest = %q, want %q", got, digest)
+	}
+	if upstreamRequests != 1 {
+		t.Errorf("upstream requests = %d, want 1", upstreamRequests)
+	}
+}
+
+func TestContainerHandler_ManifestByTag_StaleHeadChecksUpstream(t *testing.T) {
+	oldDigest := "sha256:dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
+	newDigest := "sha256:eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee"
+	currentDigest := oldDigest
+	upstreamRequests := 0
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		upstreamRequests++
+		w.Header().Set("Content-Type", "application/vnd.oci.image.manifest.v1+json")
+		w.Header().Set("Docker-Content-Digest", currentDigest)
+		w.Header().Set("ETag", `"`+currentDigest+`"`)
+		if r.Method != http.MethodHead {
+			_, _ = io.WriteString(w, `{"schemaVersion":2}`)
+		}
+	}))
+	defer upstream.Close()
+
+	proxy, _, _, _ := setupTestProxy(t)
+	proxy.HTTPClient = upstream.Client()
+	proxy.MetadataTTL = 0
+	h := &ContainerHandler{proxy: proxy, registryURL: upstream.URL, proxyURL: "http://localhost:8080"}
+
+	first := httptest.NewRecorder()
+	h.Routes().ServeHTTP(first, httptest.NewRequest(http.MethodGet, "/library/nginx/manifests/latest", nil))
+	if first.Code != http.StatusOK {
+		t.Fatalf("initial status = %d, want %d", first.Code, http.StatusOK)
+	}
+
+	currentDigest = newDigest
+	head := httptest.NewRecorder()
+	h.Routes().ServeHTTP(head, httptest.NewRequest(http.MethodHead, "/library/nginx/manifests/latest", nil))
+	if head.Code != http.StatusOK {
+		t.Fatalf("HEAD status = %d, want %d", head.Code, http.StatusOK)
+	}
+	if got := head.Header().Get("Docker-Content-Digest"); got != newDigest {
+		t.Errorf("Docker-Content-Digest = %q, want %q", got, newDigest)
+	}
+	if upstreamRequests != 2 {
+		t.Errorf("upstream requests = %d, want 2", upstreamRequests)
+	}
 }
 
 func TestContainerHandler_Routes_VersionCheck(t *testing.T) {

internal/handler/cran.go

@@ -72,7 +72,8 @@ func (h *CRANHandler) handleSourceDownload(w http.ResponseWriter, r *http.Reques
 
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "cran", name, version, filename, upstreamURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch package")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
 		return
 	}
 
@@ -106,7 +107,8 @@ func (h *CRANHandler) handleBinaryDownload(w http.ResponseWriter, r *http.Reques
 
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "cran", name, storageVersion, filename, upstreamURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch package")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
 		return
 	}
 

internal/handler/debian.go

@@ -81,7 +81,8 @@ func (h *DebianHandler) handlePackageDownload(w http.ResponseWriter, r *http.Req
 	result, err := h.proxy.GetOrFetchArtifactFromURL(
 		r.Context(), "deb", name, version, filename, downloadURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch package")
+		h.proxy.Logger.Error("failed to get debian package", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
 		return
 	}
 

internal/handler/filename_download.go

@@ -1,39 +0,0 @@
-package handler
-
-import (
-	"net/http"
-	"strings"
-)
-
-type filenameDownload struct {
-	ecosystem string
-	suffix    string
-	parseErr  string
-	fetchErr  string
-	parse     func(string) (name, version string)
-}
-
-func (p *Proxy) handleFilenameDownload(w http.ResponseWriter, r *http.Request, d filenameDownload) {
-	filename := r.PathValue("filename")
-	if filename == "" || !strings.HasSuffix(filename, d.suffix) {
-		http.Error(w, "invalid filename", http.StatusBadRequest)
-		return
-	}
-
-	name, version := d.parse(filename)
-	if name == "" || version == "" {
-		http.Error(w, d.parseErr, http.StatusBadRequest)
-		return
-	}
-
-	p.Logger.Info(d.ecosystem+" download request",
-		"name", name, "version", version, "filename", filename)
-
-	result, err := p.GetOrFetchArtifact(r.Context(), d.ecosystem, name, version, filename)
-	if err != nil {
-		p.serveArtifactError(w, err, d.fetchErr)
-		return
-	}
-
-	ServeArtifact(w, result)
-}

internal/handler/gem.go

@@ -8,6 +8,8 @@ import (
 	"net/http"
 	"strings"
 	"time"
+
+	"github.com/git-pkgs/purl"
 )
 
 const (
@@ -58,13 +60,30 @@ func (h *GemHandler) Routes() http.Handler {
 
 // handleDownload serves a gem file, fetching and caching from upstream if needed.
 func (h *GemHandler) handleDownload(w http.ResponseWriter, r *http.Request) {
-	h.proxy.handleFilenameDownload(w, r, filenameDownload{
+	filename := r.PathValue("filename")
-		ecosystem: "gem",
+	if filename == "" || !strings.HasSuffix(filename, ".gem") {
-		suffix:    ".gem",
+		http.Error(w, "invalid filename", http.StatusBadRequest)
-		parseErr:  "could not parse gem filename",
+		return
-		fetchErr:  "failed to fetch gem",
+	}
-		parse:     h.parseGemFilename,
+
-	})
+	// Extract name and version from filename (e.g., "rails-7.1.0.gem")
+	name, version := h.parseGemFilename(filename)
+	if name == "" || version == "" {
+		http.Error(w, "could not parse gem filename", http.StatusBadRequest)
+		return
+	}
+
+	h.proxy.Logger.Info("gem download request",
+		"name", name, "version", version, "filename", filename)
+
+	result, err := h.proxy.GetOrFetchArtifact(r.Context(), "gem", name, version, filename)
+	if err != nil {
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch gem", http.StatusBadGateway)
+		return
+	}
+
+	ServeArtifact(w, result)
 }
 
 // parseGemFilename extracts name and version from a gem filename.
@@ -247,7 +266,7 @@ func (h *GemHandler) fetchFilteredVersions(r *http.Request, name string) (map[st
 		return nil, err
 	}
 
-	packagePURL := canonicalPackagePURL("gem", name)
+	packagePURL := purl.MakePURLString("gem", name, "")
 	filtered := make(map[string]bool)
 
 	for _, v := range versions {

internal/handler/handler.go

@@ -48,14 +48,6 @@ func hasDotDotSegment(path string) bool {
 
 const defaultHTTPTimeout = 30 * time.Second
 
-// canonicalPackagePURL returns a versionless PURL in canonical form so cooldown
-// lookups match keys produced by config.CooldownConfig.NormalizedPackages.
-func canonicalPackagePURL(ecosystem, name string) string {
-	p := purl.MakePURL(ecosystem, name, "")
-	_ = p.Normalize()
-	return p.String()
-}
-
 const contentTypeJSON = "application/json"
 
 const headerAcceptEncoding = "Accept-Encoding"
@@ -104,7 +96,6 @@ type Proxy struct {
 	// storage at an internal one.
 	DirectServeBaseURL string
 	HTTPClient         *http.Client
-	AuthForURL         func(string) (headerName, headerValue string)
 }
 
 // NewProxy creates a new Proxy with the given dependencies.
@@ -136,18 +127,25 @@ type CacheResult struct {
 
 // GetOrFetchArtifact retrieves an artifact from cache or fetches from upstream.
 func (p *Proxy) GetOrFetchArtifact(ctx context.Context, ecosystem, name, version, filename string) (*CacheResult, error) {
-	pkgPURL := purl.MakePURLString(ecosystem, name, "")
+	if cached, err := p.GetCachedArtifact(ctx, ecosystem, name, version, filename); err != nil {
-	versionPURL := purl.MakePURLString(ecosystem, name, version)
-
-	if cached, err := p.checkCache(ctx, pkgPURL, versionPURL, filename); err != nil {
 		return nil, err
 	} else if cached != nil {
 		return cached, nil
 	}
 
+	pkgPURL := purl.MakePURLString(ecosystem, name, "")
+	versionPURL := purl.MakePURLString(ecosystem, name, version)
 	return p.fetchAndCache(ctx, ecosystem, name, version, filename, pkgPURL, versionPURL)
 }
 
+// GetCachedArtifact retrieves an artifact from cache without contacting an upstream.
+// It returns nil when no usable cache entry exists.
+func (p *Proxy) GetCachedArtifact(ctx context.Context, ecosystem, name, version, filename string) (*CacheResult, error) {
+	pkgPURL := purl.MakePURLString(ecosystem, name, "")
+	versionPURL := purl.MakePURLString(ecosystem, name, version)
+	return p.checkCache(ctx, pkgPURL, versionPURL, filename)
+}
+
 // checkCache looks up an artifact in the cache. Returns nil if not cached.
 func (p *Proxy) checkCache(ctx context.Context, pkgPURL, versionPURL, filename string) (*CacheResult, error) {
 	pkg, err := p.DB.GetPackageByPURL(pkgPURL)
@@ -252,9 +250,6 @@ func (p *Proxy) fetchAndCache(ctx context.Context, ecosystem, name, version, fil
 	// Resolve download URL
 	info, err := p.Resolver.Resolve(ctx, ecosystem, name, version)
 	if err != nil {
-		if errors.Is(err, fetch.ErrNotFound) {
-			return nil, ErrUpstreamNotFound
-		}
 		return nil, fmt.Errorf("resolving download URL: %w", err)
 	}
 
@@ -274,9 +269,6 @@ func (p *Proxy) fetchAndCache(ctx context.Context, ecosystem, name, version, fil
 	if err != nil {
 		metrics.RecordUpstreamFetch(ecosystem, fetchDuration)
 		metrics.RecordUpstreamError(ecosystem, "fetch_failed")
-		if errors.Is(err, fetch.ErrNotFound) {
-			return nil, ErrUpstreamNotFound
-		}
 		return nil, fmt.Errorf("fetching from upstream: %w", err)
 	}
 	metrics.RecordUpstreamFetch(ecosystem, fetchDuration)
@@ -406,7 +398,6 @@ func (p *Proxy) ProxyUpstream(w http.ResponseWriter, r *http.Request, upstreamUR
 			req.Header.Set(header, v)
 		}
 	}
-	p.applyUpstreamAuth(req)
 
 	resp, err := p.HTTPClient.Do(req)
 	if err != nil {
@@ -433,7 +424,6 @@ func (p *Proxy) ProxyFile(w http.ResponseWriter, r *http.Request, upstreamURL st
 		http.Error(w, "failed to create request", http.StatusInternalServerError)
 		return
 	}
-	p.applyUpstreamAuth(req)
 
 	resp, err := p.HTTPClient.Do(req)
 	if err != nil {
@@ -460,18 +450,7 @@ func JSONError(w http.ResponseWriter, status int, message string) {
 }
 
 // ErrUpstreamNotFound indicates the upstream returned 404.
-var ErrUpstreamNotFound = fmt.Errorf("upstream: %w", fetch.ErrNotFound)
+var ErrUpstreamNotFound = fmt.Errorf("upstream: not found")
-
-// serveArtifactError writes response for a failed fetch:
-// 404 when upstream reports artifact missing, 502 otherwise.
-func (p *Proxy) serveArtifactError(w http.ResponseWriter, err error, clientMsg string) {
-	if errors.Is(err, ErrUpstreamNotFound) {
-		http.Error(w, "not found", http.StatusNotFound)
-		return
-	}
-	p.Logger.Error("failed to get artifact", "error", err)
-	http.Error(w, clientMsg, http.StatusBadGateway)
-}
 
 // errStale304 is returned when upstream sends 304 but the cached file is missing.
 var errStale304 = fmt.Errorf("upstream returned 304 but cached file is missing")
@@ -574,7 +553,6 @@ func (p *Proxy) fetchUpstreamMetadata(ctx context.Context, upstreamURL string, e
 		return nil, "", "", zeroTime, fmt.Errorf("creating request: %w", err)
 	}
 	req.Header.Set("Accept", accept)
-	p.applyUpstreamAuth(req)
 
 	if entry != nil && entry.ETag.Valid {
 		req.Header.Set("If-None-Match", entry.ETag.String)
@@ -764,7 +742,6 @@ func (p *Proxy) proxyMetadataStream(w http.ResponseWriter, r *http.Request, upst
 		accept = acceptHeaders[0]
 	}
 	req.Header.Set("Accept", accept)
-	p.applyUpstreamAuth(req)
 
 	for _, header := range []string{headerAcceptEncoding, "If-Modified-Since", "If-None-Match"} {
 		if v := r.Header.Get(header); v != "" {
@@ -789,17 +766,6 @@ func (p *Proxy) proxyMetadataStream(w http.ResponseWriter, r *http.Request, upst
 	_, _ = io.Copy(w, resp.Body)
 }
 
-func (p *Proxy) applyUpstreamAuth(req *http.Request) {
-	if p.AuthForURL == nil {
-		return
-	}
-
-	headerName, headerValue := p.AuthForURL(req.URL.String())
-	if headerName != "" && headerValue != "" {
-		req.Header.Set(headerName, headerValue)
-	}
-}
-
 // GetOrFetchArtifactFromURL retrieves an artifact from cache or fetches from a specific URL.
 // This is useful for registries where download URLs are determined from metadata.
 func (p *Proxy) GetOrFetchArtifactFromURL(ctx context.Context, ecosystem, name, version, filename, downloadURL string) (*CacheResult, error) {
@@ -807,18 +773,16 @@ func (p *Proxy) GetOrFetchArtifactFromURL(ctx context.Context, ecosystem, name,
 }
 
 // GetOrFetchArtifactFromURLWithHeaders retrieves an artifact from cache or fetches from a URL
-// with additional HTTP headers. This is needed for registries that require authentication
+// with additional request-specific HTTP headers.
-// (e.g. Docker Hub requires a Bearer token even for public images).
 func (p *Proxy) GetOrFetchArtifactFromURLWithHeaders(ctx context.Context, ecosystem, name, version, filename, downloadURL string, headers http.Header) (*CacheResult, error) {
-	pkgPURL := purl.MakePURLString(ecosystem, name, "")
+	if cached, err := p.GetCachedArtifact(ctx, ecosystem, name, version, filename); err != nil {
-	versionPURL := purl.MakePURLString(ecosystem, name, version)
-
-	if cached, err := p.checkCache(ctx, pkgPURL, versionPURL, filename); err != nil {
 		return nil, err
 	} else if cached != nil {
 		return cached, nil
 	}
 
+	pkgPURL := purl.MakePURLString(ecosystem, name, "")
+	versionPURL := purl.MakePURLString(ecosystem, name, version)
 	return p.fetchAndCacheFromURL(ctx, ecosystem, name, version, filename, pkgPURL, versionPURL, downloadURL, headers)
 }
 
@@ -828,9 +792,6 @@ func (p *Proxy) fetchAndCacheFromURL(ctx context.Context, ecosystem, name, versi
 
 	artifact, err := p.Fetcher.FetchWithHeaders(ctx, downloadURL, headers)
 	if err != nil {
-		if errors.Is(err, fetch.ErrNotFound) {
-			return nil, ErrUpstreamNotFound
-		}
 		return nil, fmt.Errorf("fetching from upstream: %w", err)
 	}
 

internal/handler/handler_test.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"database/sql"
 	"errors"
-	"fmt"
 	"io"
 	"log/slog"
 	"net/http"
@@ -14,9 +13,9 @@ import (
 	"testing"
 	"time"
 
-	"github.com/git-pkgs/proxy/internal/config"
 	"github.com/git-pkgs/proxy/internal/database"
 	"github.com/git-pkgs/proxy/internal/storage"
+	"github.com/git-pkgs/purl"
 	"github.com/git-pkgs/registries/fetch"
 )
 
@@ -152,7 +151,7 @@ func seedPackage(t *testing.T, db *database.DB, store *mockStorage, ecosystem, n
 	t.Helper()
 
 	pkg := &database.Package{
-		PURL:      fmt.Sprintf("pkg:%s/%s", ecosystem, name),
+		PURL:      purl.MakePURLString(ecosystem, name, ""),
 		Ecosystem: ecosystem,
 		Name:      name,
 	}
@@ -160,7 +159,7 @@ func seedPackage(t *testing.T, db *database.DB, store *mockStorage, ecosystem, n
 		t.Fatalf("failed to upsert package: %v", err)
 	}
 
-	versionPURL := fmt.Sprintf("pkg:%s/%s@%s", ecosystem, name, version)
+	versionPURL := purl.MakePURLString(ecosystem, name, version)
 	ver := &database.Version{
 		PURL:        versionPURL,
 		PackagePURL: pkg.PURL,
@@ -1011,33 +1010,3 @@ func TestProxyCached_FreshResponse_NoWarningHeader(t *testing.T) {
 		t.Errorf("Warning should be empty for fresh response, got %q", got)
 	}
 }
-
-// TestCanonicalPackagePURLMatchesConfig ensures the runtime cooldown lookup key
-// agrees with config.CooldownConfig.NormalizedPackages for the same package,
-// so a configured override is actually found regardless of how the user wrote it.
-func TestCanonicalPackagePURLMatchesConfig(t *testing.T) {
-	tests := []struct {
-		ecosystem   string
-		requestName string
-		configKey   string
-	}{
-		{"npm", "@babel/core", "pkg:npm/@babel/core"},
-		{"npm", "@babel/core", "pkg:npm/%40babel/core"},
-		{"npm", "@typescript/typescript-darwin-arm64", "pkg:npm/@typescript/typescript-darwin-arm64"},
-		{"pypi", "Django", "pkg:pypi/Django"},
-		{"pypi", "django", "pkg:pypi/Django"},
-		{"composer", "symfony/console", "pkg:composer/Symfony/Console"},
-		{"cargo", "serde", "pkg:cargo/serde"},
-	}
-	for _, tt := range tests {
-		t.Run(tt.ecosystem+"/"+tt.requestName+"<="+tt.configKey, func(t *testing.T) {
-			cfg := config.CooldownConfig{Packages: map[string]string{tt.configKey: "1d"}}
-			normalized := cfg.NormalizedPackages()
-
-			lookup := canonicalPackagePURL(tt.ecosystem, tt.requestName)
-			if _, ok := normalized[lookup]; !ok {
-				t.Errorf("lookup key %q not found in normalized config %v", lookup, normalized)
-			}
-		})
-	}
-}

internal/handler/hex.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/git-pkgs/purl"
 	"google.golang.org/protobuf/encoding/protowire"
 )
 
@@ -53,13 +54,30 @@ func (h *HexHandler) Routes() http.Handler {
 
 // handleDownload serves a package tarball, fetching and caching from upstream if needed.
 func (h *HexHandler) handleDownload(w http.ResponseWriter, r *http.Request) {
-	h.proxy.handleFilenameDownload(w, r, filenameDownload{
+	filename := r.PathValue("filename")
-		ecosystem: "hex",
+	if filename == "" || !strings.HasSuffix(filename, ".tar") {
-		suffix:    ".tar",
+		http.Error(w, "invalid filename", http.StatusBadRequest)
-		parseErr:  "could not parse tarball filename",
+		return
-		fetchErr:  "failed to fetch package",
+	}
-		parse:     h.parseTarballFilename,
+
-	})
+	// Extract name and version from filename (e.g., "phoenix-1.7.10.tar")
+	name, version := h.parseTarballFilename(filename)
+	if name == "" || version == "" {
+		http.Error(w, "could not parse tarball filename", http.StatusBadRequest)
+		return
+	}
+
+	h.proxy.Logger.Info("hex download request",
+		"name", name, "version", version, "filename", filename)
+
+	result, err := h.proxy.GetOrFetchArtifact(r.Context(), "hex", name, version, filename)
+	if err != nil {
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
+		return
+	}
+
+	ServeArtifact(w, result)
 }
 
 // parseTarballFilename extracts name and version from a hex tarball filename.
@@ -219,7 +237,7 @@ func (h *HexHandler) fetchFilteredVersions(r *http.Request, name string) (map[st
 		return nil, err
 	}
 
-	packagePURL := canonicalPackagePURL("hex", name)
+	packagePURL := purl.MakePURLString("hex", name, "")
 	filtered := make(map[string]bool)
 
 	for _, release := range pkg.Releases {

internal/handler/julia.go

@@ -90,7 +90,8 @@ func (h *JuliaHandler) handleRegistry(w http.ResponseWriter, r *http.Request) {
 	upstreamURL := h.upstreamURL + r.URL.Path
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "julia", juliaRegistryName, hash, hash+".tar.gz", upstreamURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch registry")
+		h.proxy.Logger.Error("failed to get registry", "error", err)
+		http.Error(w, "failed to fetch registry", http.StatusBadGateway)
 		return
 	}
 
@@ -118,7 +119,8 @@ func (h *JuliaHandler) handlePackage(w http.ResponseWriter, r *http.Request) {
 	upstreamURL := h.upstreamURL + r.URL.Path
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "julia", name, hash, hash+".tar.gz", upstreamURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch package")
+		h.proxy.Logger.Error("failed to get package", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
 		return
 	}
 
@@ -139,7 +141,8 @@ func (h *JuliaHandler) handleArtifact(w http.ResponseWriter, r *http.Request) {
 	upstreamURL := h.upstreamURL + r.URL.Path
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "julia", juliaArtifactName, hash, hash+".tar.gz", upstreamURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch artifact")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch artifact", http.StatusBadGateway)
 		return
 	}
 

internal/handler/maven.go

@@ -130,7 +130,12 @@ func (h *MavenHandler) handleDownload(w http.ResponseWriter, r *http.Request, ur
 		}
 	}
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch artifact")
+		if errors.Is(err, ErrUpstreamNotFound) {
+			http.Error(w, "not found", http.StatusNotFound)
+			return
+		}
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch artifact", http.StatusBadGateway)
 		return
 	}
 

internal/handler/notfound_ecosystems_test.go

@@ -1,151 +0,0 @@
-package handler
-
-import (
-	"context"
-	"net/http"
-	"net/http/httptest"
-	"strings"
-	"testing"
-
-	"github.com/git-pkgs/registries/fetch"
-)
-
-func TestArtifactDownloadUpstreamNotFoundReturns404(t *testing.T) {
-	tests := []struct {
-		name    string
-		path    string
-		handler func(p *Proxy) http.Handler
-	}{
-		{"debian", "/pool/main/n/nginx/nginx_1.18.0-6_amd64.deb",
-			func(p *Proxy) http.Handler { return NewDebianHandler(p, "http://localhost").Routes() }},
-		{"rpm", "/releases/39/Everything/x86_64/os/Packages/n/nginx-1.24.0-1.fc39.x86_64.rpm",
-			func(p *Proxy) http.Handler { return NewRPMHandler(p, "http://localhost").Routes() }},
-		{"nuget", "/v3-flatcontainer/newtonsoft.json/13.0.3/newtonsoft.json.13.0.3.nupkg",
-			func(p *Proxy) http.Handler { return NewNuGetHandler(p, "http://localhost").Routes() }},
-		{"pypi", "/packages/packages/ab/cd/ef0123456789/requests-2.31.0-py3-none-any.whl",
-			func(p *Proxy) http.Handler { return NewPyPIHandler(p, "http://localhost").Routes() }},
-		{"cran", "/src/contrib/ggplot2_3.4.4.tar.gz",
-			func(p *Proxy) http.Handler { return NewCRANHandler(p, "http://localhost").Routes() }},
-		{"conda", "/conda-forge/linux-64/numpy-1.26.0-py311_0.tar.bz2",
-			func(p *Proxy) http.Handler { return NewCondaHandler(p, "http://localhost").Routes() }},
-		{"conan", "/v1/files/zlib/1.3.1/_/_/0/recipe/conan_sources.tgz",
-			func(p *Proxy) http.Handler { return NewConanHandler(p, "http://localhost").Routes() }},
-		{"gem", "/gems/rails-7.1.0.gem",
-			func(p *Proxy) http.Handler { return NewGemHandler(p, "http://localhost").Routes() }},
-		{"hex", "/tarballs/phoenix-1.7.10.tar",
-			func(p *Proxy) http.Handler { return NewHexHandler(p, "http://localhost").Routes() }},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			proxy, _, _, fetcher := setupTestProxy(t)
-			fetcher.fetchErr = fetch.ErrNotFound
-
-			srv := httptest.NewServer(tt.handler(proxy))
-			defer srv.Close()
-
-			resp, err := http.Get(srv.URL + tt.path)
-			if err != nil {
-				t.Fatalf("request failed: %v", err)
-			}
-			defer func() { _ = resp.Body.Close() }()
-
-			if resp.StatusCode != http.StatusNotFound {
-				t.Errorf("want 404 for missing upstream artifact, got %d", resp.StatusCode)
-			}
-		})
-	}
-}
-
-func TestJuliaPackageUpstreamNotFoundReturns404(t *testing.T) {
-	proxy, _, _, fetcher := setupTestProxy(t)
-	fetcher.fetchErr = fetch.ErrNotFound
-
-	dead := httptest.NewServer(http.NotFoundHandler())
-	defer dead.Close()
-
-	h := NewJuliaHandler(proxy, "http://localhost")
-	h.upstreamURL = dead.URL
-
-	srv := httptest.NewServer(h.Routes())
-	defer srv.Close()
-
-	resp, err := http.Get(srv.URL +
-		"/package/7876af07-990d-54b4-ab0e-23690620f79a/0123456789abcdef0123456789abcdef01234567")
-	if err != nil {
-		t.Fatalf("request failed: %v", err)
-	}
-	defer func() { _ = resp.Body.Close() }()
-
-	if resp.StatusCode != http.StatusNotFound {
-		t.Errorf("want 404 for missing upstream package, got %d", resp.StatusCode)
-	}
-}
-
-func TestComposerDownloadUpstreamNotFoundReturns404(t *testing.T) {
-	proxy, _, _, fetcher := setupTestProxy(t)
-	fetcher.fetchErr = fetch.ErrNotFound
-
-	meta := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if r.URL.Path == "/p2/monolog/monolog.json" {
-			_, _ = w.Write([]byte(`{
-				"packages": {
-					"monolog/monolog": [
-						{"version": "2.9.1", "dist": {"url": "https://example.com/monolog-2.9.1.zip", "type": "zip"}}
-					]
-				}
-			}`))
-			return
-		}
-		http.NotFound(w, r)
-	}))
-	defer meta.Close()
-
-	h := &ComposerHandler{proxy: proxy, repoURL: meta.URL, proxyURL: "http://localhost"}
-	srv := httptest.NewServer(h.Routes())
-	defer srv.Close()
-
-	resp, err := http.Get(srv.URL + "/files/monolog/monolog/2.9.1/monolog-2.9.1.zip")
-	if err != nil {
-		t.Fatalf("request failed: %v", err)
-	}
-	defer func() { _ = resp.Body.Close() }()
-
-	if resp.StatusCode != http.StatusNotFound {
-		t.Errorf("want 404 for missing upstream dist, got %d", resp.StatusCode)
-	}
-}
-
-func TestContainerBlobUpstreamNotFoundReturns404(t *testing.T) {
-	authServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/json")
-		_, _ = w.Write([]byte(`{"token": "test-token-123"}`))
-	}))
-	defer authServer.Close()
-
-	proxy, _, _, _ := setupTestProxy(t)
-	proxy.Fetcher = &mockFetcherWithHeaders{
-		fetchFn: func(_ context.Context, _ string, _ http.Header) (*fetch.Artifact, error) {
-			return nil, fetch.ErrNotFound
-		},
-	}
-
-	h := &ContainerHandler{
-		proxy:       proxy,
-		registryURL: "https://registry-1.docker.io",
-		authURL:     authServer.URL,
-		proxyURL:    "http://localhost:8080",
-	}
-
-	req := httptest.NewRequest(http.MethodGet,
-		"/library/nginx/blobs/sha256:abc123def456abc123def456abc123def456abc123def456abc123def456abcd", nil)
-	w := httptest.NewRecorder()
-	h.Routes().ServeHTTP(w, req)
-
-	if w.Code != http.StatusNotFound {
-		t.Errorf("want 404 for missing upstream blob, got %d; body: %s", w.Code, w.Body.String())
-	}
-	if !strings.Contains(w.Body.String(), "BLOB_UNKNOWN") {
-		t.Errorf("want BLOB_UNKNOWN error code in body, got: %s", w.Body.String())
-	}
-}

internal/handler/notfound_test.go

@@ -1,83 +0,0 @@
-package handler
-
-import (
-	"context"
-	"errors"
-	"io"
-	"net/http"
-	"net/http/httptest"
-	"strings"
-	"testing"
-
-	"github.com/git-pkgs/registries/fetch"
-)
-
-func TestErrUpstreamNotFoundWrapsFetchErrNotFound(t *testing.T) {
-	if !errors.Is(ErrUpstreamNotFound, fetch.ErrNotFound) {
-		t.Fatal("ErrUpstreamNotFound does not wrap fetch.ErrNotFound")
-	}
-}
-
-func TestGetOrFetchArtifactFromURL_NotFound(t *testing.T) {
-	proxy, _, _, fetcher := setupTestProxy(t)
-	fetcher.fetchErr = fetch.ErrNotFound
-
-	_, err := proxy.GetOrFetchArtifactFromURL(context.Background(),
-		"maven", "org.example:missing", "1.0", "missing-1.0.jar",
-		"http://upstream.test/org/example/missing/1.0/missing-1.0.jar")
-
-	if !errors.Is(err, ErrUpstreamNotFound) {
-		t.Fatalf("want ErrUpstreamNotFound, got %v", err)
-	}
-}
-
-func TestMavenHandler_UpstreamNotFoundReturns404(t *testing.T) {
-	proxy, _, _, fetcher := setupTestProxy(t)
-	fetcher.fetchErr = fetch.ErrNotFound
-
-	h := NewMavenHandler(proxy, "http://localhost", "http://upstream.test", "http://portal.test")
-	srv := httptest.NewServer(h.Routes())
-	defer srv.Close()
-
-	resp, err := http.Get(srv.URL + "/org/example/missing/1.0/missing-1.0.jar")
-	if err != nil {
-		t.Fatalf("request failed: %v", err)
-	}
-	defer func() { _ = resp.Body.Close() }()
-
-	if resp.StatusCode != http.StatusNotFound {
-		t.Errorf("want 404 for missing upstream artifact, got %d", resp.StatusCode)
-	}
-}
-
-func TestMavenHandler_PluginPortalFallback(t *testing.T) {
-	proxy, _, _, fetcher := setupTestProxy(t)
-	fetcher.fetchErrByURL = map[string]error{
-		"http://upstream.test/org/example/plugin/1.0/plugin-1.0.jar": fetch.ErrNotFound,
-	}
-	fetcher.artifact = &fetch.Artifact{
-		Body:        io.NopCloser(strings.NewReader("portal artifact")),
-		ContentType: "application/java-archive",
-	}
-
-	h := NewMavenHandler(proxy, "http://localhost", "http://upstream.test", "http://portal.test")
-	srv := httptest.NewServer(h.Routes())
-	defer srv.Close()
-
-	resp, err := http.Get(srv.URL + "/org/example/plugin/1.0/plugin-1.0.jar")
-	if err != nil {
-		t.Fatalf("request failed: %v", err)
-	}
-	defer func() { _ = resp.Body.Close() }()
-
-	if resp.StatusCode != http.StatusOK {
-		t.Fatalf("want 200 via plugin portal fallback, got %d", resp.StatusCode)
-	}
-	body, _ := io.ReadAll(resp.Body)
-	if string(body) != "portal artifact" {
-		t.Errorf("want portal artifact body, got %q", body)
-	}
-	if fetcher.fetchedURL != "http://portal.test/org/example/plugin/1.0/plugin-1.0.jar" {
-		t.Errorf("fallback did not hit plugin portal, last URL: %s", fetcher.fetchedURL)
-	}
-}

internal/handler/npm.go

@@ -9,6 +9,8 @@ import (
 	"sort"
 	"strings"
 	"time"
+
+	"github.com/git-pkgs/purl"
 )
 
 const (
@@ -25,14 +27,10 @@ type NPMHandler struct {
 }
 
 // NewNPMHandler creates a new npm protocol handler.
-func NewNPMHandler(proxy *Proxy, proxyURL, upstreamURL string) *NPMHandler {
+func NewNPMHandler(proxy *Proxy, proxyURL string) *NPMHandler {
-	if strings.TrimSpace(upstreamURL) == "" {
-		upstreamURL = npmUpstream
-	}
-
 	return &NPMHandler{
 		proxy:       proxy,
-		upstreamURL: strings.TrimSuffix(upstreamURL, "/"),
+		upstreamURL: npmUpstream,
 		proxyURL:    strings.TrimSuffix(proxyURL, "/"),
 	}
 }
@@ -136,7 +134,7 @@ func (h *NPMHandler) applyCooldownFiltering(metadata map[string]any, versions ma
 		return
 	}
 
-	packagePURL := canonicalPackagePURL("npm", packageName)
+	packagePURL := purl.MakePURLString("npm", packageName, "")
 
 	for version := range versions {
 		publishedStr, ok := timeMap[version].(string)
@@ -265,20 +263,8 @@ func (h *NPMHandler) handleDownload(w http.ResponseWriter, r *http.Request) {
 	h.proxy.Logger.Info("npm download request",
 		"package", packageName, "version", version, "filename", filename)
 
-	downloadURL := fmt.Sprintf(
+	result, err := h.proxy.GetOrFetchArtifact(r.Context(), "npm", packageName, version, filename)
-		"%s/%s/-/%s",
-		h.upstreamURL,
-		escapeNPMDownloadPackage(packageName),
-		url.PathEscape(filename),
-	)
-	result, err := h.proxy.GetOrFetchArtifactFromURL(
-		r.Context(), "npm", packageName, version, filename, downloadURL,
-	)
 	if err != nil {
-		if errors.Is(err, ErrUpstreamNotFound) {
-			JSONError(w, http.StatusNotFound, "package not found")
-			return
-		}
 		h.proxy.Logger.Error("failed to get artifact", "error", err)
 		JSONError(w, http.StatusBadGateway, "failed to fetch package")
 		return
@@ -287,14 +273,6 @@ func (h *NPMHandler) handleDownload(w http.ResponseWriter, r *http.Request) {
 	ServeArtifact(w, result)
 }
 
-func escapeNPMDownloadPackage(packageName string) string {
-	scope, name, scoped := strings.Cut(packageName, "/")
-	if scoped && strings.HasPrefix(scope, "@") && len(scope) > 1 && name != "" && !strings.Contains(name, "/") {
-		return url.PathEscape(scope) + "/" + url.PathEscape(name)
-	}
-	return url.PathEscape(packageName)
-}
-
 // extractPackageName extracts the package name from the request path.
 // Handles both scoped (@scope/name) and unscoped (name) packages.
 func (h *NPMHandler) extractPackageName(r *http.Request) string {

internal/handler/npm_test.go

@@ -2,16 +2,13 @@ package handler
 
 import (
 	"encoding/json"
-	"io"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
-	"strings"
 	"testing"
 	"time"
 
 	"github.com/git-pkgs/cooldown"
-	"github.com/git-pkgs/registries/fetch"
 )
 
 const testVersion100 = "1.0.0"
@@ -49,86 +46,6 @@ func TestNPMExtractVersionFromFilename(t *testing.T) {
 	}
 }
 
-func TestNPMHandlerUsesConfiguredUpstream(t *testing.T) {
-	t.Run("metadata", func(t *testing.T) {
-		var requestPath, authHeader string
-		upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			requestPath = r.URL.Path
-			authHeader = r.Header.Get("Authorization")
-			if authHeader != "Bearer npm-token" {
-				w.WriteHeader(http.StatusUnauthorized)
-				return
-			}
-			w.Header().Set("Content-Type", "application/json")
-			_, _ = io.WriteString(w, `{"versions":{}}`)
-		}))
-		defer upstream.Close()
-
-		proxy, _, _, _ := setupTestProxy(t)
-		proxy.HTTPClient = upstream.Client()
-		proxy.AuthForURL = func(string) (string, string) {
-			return "Authorization", "Bearer npm-token"
-		}
-		h := NewNPMHandler(proxy, "http://proxy.test", upstream.URL+"/root/")
-
-		req := httptest.NewRequest(http.MethodGet, "/testpkg", nil)
-		w := httptest.NewRecorder()
-		h.Routes().ServeHTTP(w, req)
-
-		if w.Code != http.StatusOK {
-			t.Fatalf("status = %d, want %d; body: %s", w.Code, http.StatusOK, w.Body.String())
-		}
-		if requestPath != "/root/testpkg" {
-			t.Errorf("upstream path = %q, want %q", requestPath, "/root/testpkg")
-		}
-		if authHeader != "Bearer npm-token" {
-			t.Errorf("Authorization = %q, want %q", authHeader, "Bearer npm-token")
-		}
-	})
-
-	t.Run("download", func(t *testing.T) {
-		proxy, _, _, artifactFetcher := setupTestProxy(t)
-		artifactFetcher.artifact = &fetch.Artifact{
-			Body:        io.NopCloser(strings.NewReader("package")),
-			ContentType: "application/gzip",
-		}
-		h := NewNPMHandler(proxy, "http://proxy.test", "https://npm.example.test/root/")
-
-		req := httptest.NewRequest(http.MethodGet, "/testpkg/-/testpkg-1.0.0.tgz", nil)
-		w := httptest.NewRecorder()
-		h.Routes().ServeHTTP(w, req)
-
-		if w.Code != http.StatusOK {
-			t.Fatalf("status = %d, want %d; body: %s", w.Code, http.StatusOK, w.Body.String())
-		}
-		want := "https://npm.example.test/root/testpkg/-/testpkg-1.0.0.tgz"
-		if artifactFetcher.fetchedURL != want {
-			t.Errorf("fetched URL = %q, want %q", artifactFetcher.fetchedURL, want)
-		}
-	})
-
-	t.Run("scoped download", func(t *testing.T) {
-		proxy, _, _, artifactFetcher := setupTestProxy(t)
-		artifactFetcher.artifact = &fetch.Artifact{
-			Body:        io.NopCloser(strings.NewReader("package")),
-			ContentType: "application/gzip",
-		}
-		h := NewNPMHandler(proxy, "http://proxy.test", "https://npm.example.test/root/")
-
-		req := httptest.NewRequest(http.MethodGet, "/@scope/name/-/name-1.0.0.tgz", nil)
-		w := httptest.NewRecorder()
-		h.Routes().ServeHTTP(w, req)
-
-		if w.Code != http.StatusOK {
-			t.Fatalf("status = %d, want %d; body: %s", w.Code, http.StatusOK, w.Body.String())
-		}
-		want := "https://npm.example.test/root/@scope/name/-/name-1.0.0.tgz"
-		if artifactFetcher.fetchedURL != want {
-			t.Errorf("fetched URL = %q, want %q", artifactFetcher.fetchedURL, want)
-		}
-	})
-}
-
 func TestNPMRewriteMetadata(t *testing.T) {
 	h := &NPMHandler{
 		proxy:    testProxy(),

internal/handler/nuget.go

@@ -8,6 +8,8 @@ import (
 	"net/http"
 	"strings"
 	"time"
+
+	"github.com/git-pkgs/purl"
 )
 
 const (
@@ -269,7 +271,7 @@ func (h *NuGetHandler) applyCooldownFiltering(body []byte) ([]byte, error) {
 				}
 			}
 
-			packagePURL := canonicalPackagePURL("nuget", strings.ToLower(id))
+			packagePURL := purl.MakePURLString("nuget", strings.ToLower(id), "")
 
 			if !h.proxy.Cooldown.IsAllowed("nuget", packagePURL, publishedAt) {
 				h.proxy.Logger.Info("cooldown: filtering nuget version",
@@ -314,7 +316,8 @@ func (h *NuGetHandler) handleDownload(w http.ResponseWriter, r *http.Request) {
 
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "nuget", name, version, filename, upstreamURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch package")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
 		return
 	}
 

internal/handler/pub.go

@@ -7,6 +7,8 @@ import (
 	"net/http"
 	"strings"
 	"time"
+
+	"github.com/git-pkgs/purl"
 )
 
 const (
@@ -67,7 +69,8 @@ func (h *PubHandler) handleDownload(w http.ResponseWriter, r *http.Request) {
 
 	result, err := h.proxy.GetOrFetchArtifact(r.Context(), "pub", name, version, filename)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch package")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
 		return
 	}
 
@@ -124,7 +127,7 @@ func (h *PubHandler) rewriteMetadata(name string, body []byte) ([]byte, error) {
 		return body, nil
 	}
 
-	packagePURL := canonicalPackagePURL("pub", name)
+	packagePURL := purl.MakePURLString("pub", name, "")
 	filtered := h.filterAndRewriteVersions(name, packagePURL, versions)
 	metadata["versions"] = filtered
 

internal/handler/pypi.go

@@ -12,6 +12,8 @@ import (
 	"regexp"
 	"strings"
 	"time"
+
+	"github.com/git-pkgs/purl"
 )
 
 const (
@@ -129,7 +131,7 @@ func (h *PyPIHandler) fetchFilteredVersions(r *http.Request, name string) map[st
 		return nil
 	}
 
-	packagePURL := canonicalPackagePURL("pypi", name)
+	packagePURL := purl.MakePURLString("pypi", name, "")
 	filtered := make(map[string]bool)
 
 	for version, files := range releases {
@@ -260,7 +262,7 @@ func (h *PyPIHandler) rewriteJSONMetadata(body []byte) ([]byte, error) {
 	packageName, _ := extractPyPIName(metadata)
 	packagePURL := ""
 	if packageName != "" {
-		packagePURL = canonicalPackagePURL("pypi", packageName)
+		packagePURL = purl.MakePURLString("pypi", packageName, "")
 	}
 
 	h.filterAndRewriteReleases(metadata, packageName, packagePURL)
@@ -426,7 +428,8 @@ func (h *PyPIHandler) handleDownload(w http.ResponseWriter, r *http.Request) {
 
 	result, err := h.proxy.GetOrFetchArtifactFromURL(r.Context(), "pypi", name, version, filename, upstreamURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch package")
+		h.proxy.Logger.Error("failed to get artifact", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
 		return
 	}
 

internal/handler/rpm.go

@@ -83,7 +83,8 @@ func (h *RPMHandler) handlePackageDownload(w http.ResponseWriter, r *http.Reques
 	result, err := h.proxy.GetOrFetchArtifactFromURL(
 		r.Context(), "rpm", name, version, filename, downloadURL)
 	if err != nil {
-		h.proxy.serveArtifactError(w, err, "failed to fetch package")
+		h.proxy.Logger.Error("failed to get rpm package", "error", err)
+		http.Error(w, "failed to fetch package", http.StatusBadGateway)
 		return
 	}
 

internal/httpclient/transport.go

@@ -0,0 +1,418 @@
+// Package httpclient provides authentication-aware HTTP transports for upstream requests.
+package httpclient
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+	"time"
+)
+
+const (
+	defaultTokenLifetime  = 60 * time.Second
+	tokenExpirySkew       = 5 * time.Second
+	maxTokenResponseSize  = 1 << 20
+	shortTokenSkewDivisor = 10
+)
+
+// AuthFunc returns a configured authentication header for a URL.
+type AuthFunc func(url string) (headerName, headerValue string)
+
+// Transport adds configured authentication and follows OCI Bearer challenges.
+type Transport struct {
+	base       http.RoundTripper
+	authForURL AuthFunc
+
+	mu         sync.Mutex
+	tokens     map[string]cachedToken
+	challenges map[string]bearerChallenge
+}
+
+type cachedToken struct {
+	value     string
+	expiresAt time.Time
+}
+
+type bearerChallenge struct {
+	realm   string
+	service string
+	scopes  []string
+}
+
+type tokenResponse struct {
+	Token       string `json:"token"`
+	AccessToken string `json:"access_token"`
+	ExpiresIn   int64  `json:"expires_in"`
+	IssuedAt    string `json:"issued_at"`
+}
+
+// NewTransport creates an authentication-aware transport around base.
+func NewTransport(base http.RoundTripper, authForURL AuthFunc) *Transport {
+	if base == nil {
+		base = http.DefaultTransport
+	}
+	return &Transport{
+		base:       base,
+		authForURL: authForURL,
+		tokens:     make(map[string]cachedToken),
+		challenges: make(map[string]bearerChallenge),
+	}
+}
+
+// RoundTrip implements http.RoundTripper.
+func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
+	outbound := cloneRequest(req)
+	t.applyAuthentication(outbound, req.Header.Get("Authorization") != "")
+
+	resp, err := t.base.RoundTrip(outbound)
+	if err != nil || resp.StatusCode != http.StatusUnauthorized {
+		return resp, err
+	}
+	if registryProtectionSpace(req.URL) == "" {
+		return resp, nil
+	}
+
+	challenge, ok := parseBearerChallenge(resp.Header.Values("WWW-Authenticate"))
+	if !ok || !canReplay(req) {
+		return resp, nil
+	}
+
+	drainAndClose(resp.Body)
+	token, err := t.token(req.Context(), challenge)
+	if err != nil {
+		return nil, fmt.Errorf("registry authentication: %w", err)
+	}
+	t.rememberChallenge(req.URL, challenge)
+
+	retry, err := cloneRequestForRetry(req)
+	if err != nil {
+		return nil, err
+	}
+	t.applyConfiguredAuthentication(retry)
+	retry.Header.Set("Authorization", "Bearer "+token)
+	return t.base.RoundTrip(retry)
+}
+
+func (t *Transport) applyAuthentication(req *http.Request, hasExplicitAuthorization bool) {
+	t.applyConfiguredAuthentication(req)
+	if hasExplicitAuthorization {
+		return
+	}
+	if token := t.cachedTokenForRequest(req.URL); token != "" {
+		req.Header.Set("Authorization", "Bearer "+token)
+	}
+}
+
+func (t *Transport) applyConfiguredAuthentication(req *http.Request) {
+	if t.authForURL == nil {
+		return
+	}
+	name, value := t.authForURL(req.URL.String())
+	if name != "" && value != "" && req.Header.Get(name) == "" {
+		req.Header.Set(name, value)
+	}
+}
+
+func (t *Transport) token(ctx context.Context, challenge bearerChallenge) (string, error) {
+	key := challenge.key()
+	if token := t.cachedToken(key); token != "" {
+		return token, nil
+	}
+
+	token, expiresAt, err := t.fetchToken(ctx, challenge)
+	if err != nil {
+		return "", err
+	}
+
+	t.mu.Lock()
+	t.tokens[key] = cachedToken{value: token, expiresAt: expiresAt}
+	t.mu.Unlock()
+	return token, nil
+}
+
+func (t *Transport) fetchToken(ctx context.Context, challenge bearerChallenge) (string, time.Time, error) {
+	tokenURL, err := url.Parse(challenge.realm)
+	if err != nil || !tokenURL.IsAbs() || (tokenURL.Scheme != "https" && tokenURL.Scheme != "http") {
+		return "", time.Time{}, fmt.Errorf("invalid token realm %q", challenge.realm)
+	}
+
+	query := tokenURL.Query()
+	if challenge.service != "" {
+		query.Set("service", challenge.service)
+	}
+	for _, scope := range challenge.scopes {
+		query.Add("scope", scope)
+	}
+	query.Set("client_id", "git-pkgs-proxy")
+	tokenURL.RawQuery = query.Encode()
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, tokenURL.String(), nil)
+	if err != nil {
+		return "", time.Time{}, err
+	}
+
+	client := &http.Client{Transport: configuredTransport{parent: t}}
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", time.Time{}, fmt.Errorf("requesting token: %w", err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode < http.StatusOK || resp.StatusCode >= http.StatusMultipleChoices {
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, maxTokenResponseSize))
+		return "", time.Time{}, fmt.Errorf("token service returned %d: %s", resp.StatusCode, strings.TrimSpace(string(body)))
+	}
+
+	var payload tokenResponse
+	if err := json.NewDecoder(io.LimitReader(resp.Body, maxTokenResponseSize)).Decode(&payload); err != nil {
+		return "", time.Time{}, fmt.Errorf("decoding token response: %w", err)
+	}
+	token := payload.Token
+	if token == "" {
+		token = payload.AccessToken
+	}
+	if token == "" {
+		return "", time.Time{}, fmt.Errorf("token response did not contain a token")
+	}
+
+	issuedAt := time.Now()
+	if payload.IssuedAt != "" {
+		if parsed, parseErr := time.Parse(time.RFC3339, payload.IssuedAt); parseErr == nil {
+			issuedAt = parsed
+		}
+	}
+	lifetime := time.Duration(payload.ExpiresIn) * time.Second
+	if lifetime <= 0 {
+		lifetime = defaultTokenLifetime
+	}
+	expiresAt := issuedAt.Add(lifetime).Add(-expirySkew(lifetime))
+	return token, expiresAt, nil
+}
+
+type configuredTransport struct {
+	parent *Transport
+}
+
+func (t configuredTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	outbound := cloneRequest(req)
+	t.parent.applyConfiguredAuthentication(outbound)
+	return t.parent.base.RoundTrip(outbound)
+}
+
+func (t *Transport) cachedTokenForRequest(requestURL *url.URL) string {
+	space := registryProtectionSpace(requestURL)
+	if space == "" {
+		return ""
+	}
+
+	t.mu.Lock()
+	challenge, ok := t.challenges[space]
+	t.mu.Unlock()
+	if !ok {
+		return ""
+	}
+	return t.cachedToken(challenge.key())
+}
+
+func (t *Transport) cachedToken(key string) string {
+	now := time.Now()
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	token, ok := t.tokens[key]
+	if !ok {
+		return ""
+	}
+	if !now.Before(token.expiresAt) {
+		delete(t.tokens, key)
+		return ""
+	}
+	return token.value
+}
+
+func (t *Transport) rememberChallenge(requestURL *url.URL, challenge bearerChallenge) {
+	space := registryProtectionSpace(requestURL)
+	if space == "" {
+		return
+	}
+	t.mu.Lock()
+	t.challenges[space] = challenge
+	t.mu.Unlock()
+}
+
+func (c bearerChallenge) key() string {
+	return c.realm + "\x00" + c.service + "\x00" + strings.Join(c.scopes, "\x00")
+}
+
+func registryProtectionSpace(u *url.URL) string {
+	const registryPrefix = "/v2/"
+	if u == nil || !strings.HasPrefix(u.Path, registryPrefix) {
+		return ""
+	}
+	rest := strings.TrimPrefix(u.Path, registryPrefix)
+	end := len(rest)
+	for _, marker := range []string{"/blobs/", "/manifests/", "/tags/", "/referrers/"} {
+		if index := strings.Index(rest, marker); index >= 0 && index < end {
+			end = index
+		}
+	}
+	if end == len(rest) || end == 0 {
+		return ""
+	}
+	return u.Scheme + "://" + u.Host + registryPrefix + rest[:end]
+}
+
+func parseBearerChallenge(values []string) (bearerChallenge, bool) {
+	for _, value := range values {
+		params, ok := bearerParameters(value)
+		if !ok || params["realm"] == "" {
+			continue
+		}
+		challenge := bearerChallenge{
+			realm:   params["realm"],
+			service: params["service"],
+		}
+		if scope := params["scope"]; scope != "" {
+			challenge.scopes = append(challenge.scopes, scope)
+		}
+		return challenge, true
+	}
+	return bearerChallenge{}, false
+}
+
+func bearerParameters(value string) (map[string]string, bool) {
+	start := findAuthScheme(value, "Bearer")
+	if start < 0 {
+		return nil, false
+	}
+	rest := value[start+len("Bearer"):]
+	params := make(map[string]string)
+	for {
+		rest = strings.TrimLeft(rest, " \t,")
+		if rest == "" {
+			break
+		}
+
+		keyEnd := strings.IndexAny(rest, "= \t,")
+		if keyEnd <= 0 {
+			break
+		}
+		key := strings.ToLower(rest[:keyEnd])
+		rest = strings.TrimLeft(rest[keyEnd:], " \t")
+		if rest == "" || rest[0] != '=' {
+			break
+		}
+		rest = strings.TrimLeft(rest[1:], " \t")
+
+		parsed, remaining, ok := parseAuthValue(rest)
+		if !ok {
+			return nil, false
+		}
+		params[key] = parsed
+		rest = remaining
+	}
+	return params, true
+}
+
+func findAuthScheme(value, scheme string) int {
+	inQuote := false
+	escaped := false
+	for index := 0; index+len(scheme) <= len(value); index++ {
+		char := value[index]
+		if escaped {
+			escaped = false
+			continue
+		}
+		if char == '\\' && inQuote {
+			escaped = true
+			continue
+		}
+		if char == '"' {
+			inQuote = !inQuote
+			continue
+		}
+		if inQuote || !strings.EqualFold(value[index:index+len(scheme)], scheme) {
+			continue
+		}
+		beforeOK := index == 0 || value[index-1] == ',' || value[index-1] == ' ' || value[index-1] == '\t'
+		after := index + len(scheme)
+		afterOK := after < len(value) && (value[after] == ' ' || value[after] == '\t')
+		if beforeOK && afterOK {
+			return index
+		}
+	}
+	return -1
+}
+
+func parseAuthValue(value string) (parsed, remaining string, ok bool) {
+	if value == "" {
+		return "", "", false
+	}
+	if value[0] != '"' {
+		end := strings.IndexAny(value, " \t,")
+		if end < 0 {
+			return value, "", true
+		}
+		return value[:end], value[end:], end > 0
+	}
+
+	var builder strings.Builder
+	escaped := false
+	for index := 1; index < len(value); index++ {
+		char := value[index]
+		if escaped {
+			builder.WriteByte(char)
+			escaped = false
+			continue
+		}
+		if char == '\\' {
+			escaped = true
+			continue
+		}
+		if char == '"' {
+			return builder.String(), value[index+1:], true
+		}
+		builder.WriteByte(char)
+	}
+	return "", "", false
+}
+
+func cloneRequest(req *http.Request) *http.Request {
+	clone := req.Clone(req.Context())
+	clone.Header = req.Header.Clone()
+	return clone
+}
+
+func canReplay(req *http.Request) bool {
+	return req.Body == nil || req.GetBody != nil
+}
+
+func cloneRequestForRetry(req *http.Request) (*http.Request, error) {
+	clone := cloneRequest(req)
+	if req.Body == nil {
+		return clone, nil
+	}
+	body, err := req.GetBody()
+	if err != nil {
+		return nil, fmt.Errorf("replaying authenticated request: %w", err)
+	}
+	clone.Body = body
+	return clone, nil
+}
+
+func expirySkew(lifetime time.Duration) time.Duration {
+	if lifetime < tokenExpirySkew*2 {
+		return lifetime / shortTokenSkewDivisor
+	}
+	return tokenExpirySkew
+}
+
+func drainAndClose(body io.ReadCloser) {
+	_, _ = io.Copy(io.Discard, io.LimitReader(body, maxTokenResponseSize))
+	_ = body.Close()
+}

internal/httpclient/transport_test.go

@@ -0,0 +1,151 @@
+package httpclient
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestTransportFollowsBearerChallengeAndCachesToken(t *testing.T) {
+	var registryRequests int
+	var tokenRequests int
+	var server *httptest.Server
+
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.URL.Path {
+		case "/token":
+			tokenRequests++
+			if got := r.URL.Query().Get("service"); got != "registry.test" {
+				t.Errorf("service = %q, want %q", got, "registry.test")
+			}
+			if got := r.URL.Query().Get("scope"); got != "repository:library/test:pull" {
+				t.Errorf("scope = %q, want %q", got, "repository:library/test:pull")
+			}
+			w.Header().Set("Content-Type", "application/json")
+			_, _ = io.WriteString(w, `{"token":"registry-token","expires_in":3600}`)
+		case "/v2/library/test/blobs/sha256:first", "/v2/library/test/blobs/sha256:second":
+			registryRequests++
+			if r.Header.Get("Authorization") != "Bearer registry-token" {
+				w.Header().Set("WWW-Authenticate", `Bearer realm="`+server.URL+`/token",service="registry.test",scope="repository:library/test:pull"`)
+				http.Error(w, "authentication required", http.StatusUnauthorized)
+				return
+			}
+			_, _ = io.WriteString(w, "blob")
+		default:
+			http.NotFound(w, r)
+		}
+	}))
+	defer server.Close()
+
+	client := &http.Client{Transport: NewTransport(http.DefaultTransport, nil)}
+	for _, digest := range []string{"sha256:first", "sha256:second"} {
+		resp, err := client.Get(server.URL + "/v2/library/test/blobs/" + digest)
+		if err != nil {
+			t.Fatalf("GET %s: %v", digest, err)
+		}
+		body, readErr := io.ReadAll(resp.Body)
+		_ = resp.Body.Close()
+		if readErr != nil {
+			t.Fatalf("read %s response: %v", digest, readErr)
+		}
+		if resp.StatusCode != http.StatusOK {
+			t.Fatalf("GET %s status = %d, want %d", digest, resp.StatusCode, http.StatusOK)
+		}
+		if string(body) != "blob" {
+			t.Errorf("GET %s body = %q, want %q", digest, body, "blob")
+		}
+	}
+
+	if tokenRequests != 1 {
+		t.Errorf("token requests = %d, want 1", tokenRequests)
+	}
+	if registryRequests != 3 {
+		t.Errorf("registry requests = %d, want 3", registryRequests)
+	}
+}
+
+func TestTransportAddsConfiguredAuthentication(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if got := r.Header.Get("X-Registry-Token"); got != "configured-token" {
+			t.Errorf("X-Registry-Token = %q, want %q", got, "configured-token")
+		}
+		w.WriteHeader(http.StatusNoContent)
+	}))
+	defer server.Close()
+
+	authForURL := func(url string) (string, string) {
+		if strings.HasPrefix(url, server.URL) {
+			return "X-Registry-Token", "configured-token"
+		}
+		return "", ""
+	}
+	client := &http.Client{Transport: NewTransport(http.DefaultTransport, authForURL)}
+
+	resp, err := client.Get(server.URL + "/metadata")
+	if err != nil {
+		t.Fatalf("GET metadata: %v", err)
+	}
+	_ = resp.Body.Close()
+	if resp.StatusCode != http.StatusNoContent {
+		t.Errorf("status = %d, want %d", resp.StatusCode, http.StatusNoContent)
+	}
+}
+
+func TestTransportPreservesExplicitAuthentication(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if got := r.Header.Get("Authorization"); got != "Bearer explicit-token" {
+			t.Errorf("Authorization = %q, want %q", got, "Bearer explicit-token")
+		}
+		w.WriteHeader(http.StatusNoContent)
+	}))
+	defer server.Close()
+
+	authForURL := func(string) (string, string) {
+		return "Authorization", "Bearer configured-token"
+	}
+	client := &http.Client{Transport: NewTransport(http.DefaultTransport, authForURL)}
+	req, err := http.NewRequest(http.MethodGet, server.URL+"/artifact", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Authorization", "Bearer explicit-token")
+
+	resp, err := client.Do(req)
+	if err != nil {
+		t.Fatalf("GET artifact: %v", err)
+	}
+	_ = resp.Body.Close()
+	if resp.StatusCode != http.StatusNoContent {
+		t.Errorf("status = %d, want %d", resp.StatusCode, http.StatusNoContent)
+	}
+}
+
+func TestTransportDoesNotFollowBearerChallengeOutsideOCIRegistry(t *testing.T) {
+	tokenRequests := 0
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/token" {
+			tokenRequests++
+			_, _ = io.WriteString(w, `{"token":"unexpected"}`)
+			return
+		}
+		w.Header().Set("WWW-Authenticate", `Bearer realm="`+server.URL+`/token"`)
+		http.Error(w, "authentication required", http.StatusUnauthorized)
+	}))
+	defer server.Close()
+
+	client := &http.Client{Transport: NewTransport(http.DefaultTransport, nil)}
+	resp, err := client.Get(server.URL + "/api/packages")
+	if err != nil {
+		t.Fatalf("GET API: %v", err)
+	}
+	_ = resp.Body.Close()
+	if resp.StatusCode != http.StatusUnauthorized {
+		t.Errorf("status = %d, want %d", resp.StatusCode, http.StatusUnauthorized)
+	}
+	if tokenRequests != 0 {
+		t.Errorf("token requests = %d, want 0", tokenRequests)
+	}
+}

internal/server/server.go

@@ -58,17 +58,19 @@ import (
 	"strings"
 	"time"
 
+	"github.com/git-pkgs/cooldown"
 	swaggerdoc "github.com/git-pkgs/proxy/docs/swagger"
 	"github.com/git-pkgs/proxy/internal/config"
-	"github.com/git-pkgs/cooldown"
 	"github.com/git-pkgs/proxy/internal/database"
 	"github.com/git-pkgs/proxy/internal/enrichment"
 	"github.com/git-pkgs/proxy/internal/handler"
+	upstreamhttp "github.com/git-pkgs/proxy/internal/httpclient"
 	"github.com/git-pkgs/proxy/internal/metrics"
 	"github.com/git-pkgs/proxy/internal/mirror"
 	"github.com/git-pkgs/proxy/internal/storage"
 	"github.com/git-pkgs/purl"
 	"github.com/git-pkgs/registries/fetch"
+	"github.com/git-pkgs/registries/safehttp"
 	"github.com/git-pkgs/spdx"
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
@@ -84,12 +86,12 @@ const (
 
 // Server is the main proxy server.
 type Server struct {
-	cfg       *config.Config
+	cfg         *config.Config
-	db        *database.DB
+	db          *database.DB
-	storage   storage.Storage
+	storage     storage.Storage
-	logger    *slog.Logger
+	logger      *slog.Logger
-	http      *http.Server
+	http        *http.Server
-	templates *Templates
+	templates   *Templates
 	cancel      context.CancelFunc
 	healthCache *healthCache
 }
@@ -156,18 +158,27 @@ func New(cfg *config.Config, logger *slog.Logger) (*Server, error) {
 
 // Start starts the HTTP server.
 func (s *Server) Start() error {
-	// Create shared components with circuit breaker
+	// Use one authentication-aware transport for metadata and artifacts so
-	baseFetcher := fetch.NewFetcher(fetch.WithAuthFunc(s.authForURL))
+	// configured credentials and cached OCI challenges apply consistently.
+	safeClient := safehttp.New(nil, safehttp.Options{})
+	authTransport := upstreamhttp.NewTransport(safeClient.Transport, upstreamhttp.AuthFunc(s.authForURL))
+	metadataClient := *safeClient
+	metadataClient.Timeout = s.cfg.ParseHTTPTimeout()
+	metadataClient.Transport = authTransport
+	artifactClient := metadataClient
+	artifactClient.Timeout = serverWriteTimeout
+
+	// Create shared components with circuit breaker.
+	baseFetcher := fetch.NewFetcher(fetch.WithHTTPClient(&artifactClient))
 	fetcher := fetch.NewCircuitBreakerFetcher(baseFetcher)
 	resolver := fetch.NewResolver()
 	cd := &cooldown.Config{
 		Default:    s.cfg.Cooldown.Default,
 		Ecosystems: s.cfg.Cooldown.Ecosystems,
-		Packages:   s.cfg.Cooldown.NormalizedPackages(),
+		Packages:   s.cfg.Cooldown.Packages,
 	}
 	proxy := handler.NewProxy(s.db, s.storage, fetcher, resolver, s.logger)
-	proxy.HTTPClient.Timeout = s.cfg.ParseHTTPTimeout()
+	proxy.HTTPClient = &metadataClient
-	proxy.AuthForURL = s.authForURL
 	proxy.Cooldown = cd
 	proxy.CacheMetadata = s.cfg.CacheMetadata
 	proxy.MetadataTTL = s.cfg.ParseMetadataTTL()
@@ -197,13 +208,8 @@ func (s *Server) Start() error {
 	})
 
 	// Mount protocol handlers
-	npmHandler := handler.NewNPMHandler(proxy, s.cfg.BaseURL, s.cfg.Upstream.NPM)
+	npmHandler := handler.NewNPMHandler(proxy, s.cfg.BaseURL)
-	cargoHandler := handler.NewCargoHandler(
+	cargoHandler := handler.NewCargoHandler(proxy, s.cfg.BaseURL)
-		proxy,
-		s.cfg.BaseURL,
-		s.cfg.Upstream.Cargo,
-		s.cfg.Upstream.CargoDownload,
-	)
 	gemHandler := handler.NewGemHandler(proxy, s.cfg.BaseURL)
 	goHandler := handler.NewGoHandler(proxy, s.cfg.BaseURL)
 	hexHandler := handler.NewHexHandler(proxy, s.cfg.BaseURL)

internal/server/server_test.go

@@ -67,13 +67,8 @@ func newTestServer(t *testing.T) *testServer {
 	r := chi.NewRouter()
 
 	// Mount handlers
-	npmHandler := handler.NewNPMHandler(proxy, cfg.BaseURL, cfg.Upstream.NPM)
+	npmHandler := handler.NewNPMHandler(proxy, cfg.BaseURL)
-	cargoHandler := handler.NewCargoHandler(
+	cargoHandler := handler.NewCargoHandler(proxy, cfg.BaseURL)
-		proxy,
-		cfg.BaseURL,
-		cfg.Upstream.Cargo,
-		cfg.Upstream.CargoDownload,
-	)
 	gemHandler := handler.NewGemHandler(proxy, cfg.BaseURL)
 	goHandler := handler.NewGoHandler(proxy, cfg.BaseURL)
 	pypiHandler := handler.NewPyPIHandler(proxy, cfg.BaseURL)