Files
mcr/internal/server/middleware.go
Kyle Isom 3314b7a618 Batch A: blob storage layer, MCIAS auth, OCI token endpoint
Phase 2 — internal/storage/:
Content-addressed blob storage with atomic writes via rename.
BlobWriter stages data in uploads dir with running SHA-256 hash,
commits by verifying digest then renaming to layers/sha256/<prefix>/<hex>.
Reader provides Open, Stat, Delete, Exists with digest validation.

Phase 3 — internal/auth/ + internal/server/:
MCIAS client with Login and ValidateToken, 30s SHA-256-keyed cache
with lazy eviction and injectable clock for testing. TLS 1.3 minimum
with optional custom CA cert.
Chi router with RequireAuth middleware (Bearer token extraction,
WWW-Authenticate header, OCI error format), token endpoint (Basic
auth → bearer exchange via MCIAS), and /v2/ version check handler.

52 tests passing (14 storage + 9 auth + 9 server + 20 existing).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-19 14:51:19 -07:00

60 lines
1.8 KiB
Go

package server
import (
"fmt"
"net/http"
"strings"
"git.wntrmute.dev/kyle/mcr/internal/auth"
)
// TokenValidator abstracts token validation so the middleware can work
// with the real MCIAS client or a test fake.
type TokenValidator interface {
ValidateToken(token string) (*auth.Claims, error)
}
// RequireAuth returns middleware that validates Bearer tokens via the
// given TokenValidator. On success the authenticated Claims are injected
// into the request context. On failure a 401 with an OCI-format error
// body and a WWW-Authenticate header is returned.
func RequireAuth(validator TokenValidator, serviceName string) func(http.Handler) http.Handler {
wwwAuth := fmt.Sprintf(`Bearer realm="/v2/token",service="%s"`, serviceName)
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
token := extractBearerToken(r)
if token == "" {
w.Header().Set("WWW-Authenticate", wwwAuth)
writeOCIError(w, "UNAUTHORIZED", http.StatusUnauthorized, "authentication required")
return
}
claims, err := validator.ValidateToken(token)
if err != nil {
w.Header().Set("WWW-Authenticate", wwwAuth)
writeOCIError(w, "UNAUTHORIZED", http.StatusUnauthorized, "authentication required")
return
}
ctx := auth.ContextWithClaims(r.Context(), claims)
next.ServeHTTP(w, r.WithContext(ctx))
})
}
}
// extractBearerToken parses a "Bearer <token>" value from the
// Authorization header. It returns an empty string if the header is
// missing or malformed.
func extractBearerToken(r *http.Request) string {
h := r.Header.Get("Authorization")
if h == "" {
return ""
}
const prefix = "Bearer "
if !strings.HasPrefix(h, prefix) {
return ""
}
return strings.TrimSpace(h[len(prefix):])
}