Ilia Denisov
71 lines
2.3 KiB
Go
71 lines
2.3 KiB
Go
// Package userid extracts the calling user identifier from the trusted
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// `X-User-ID` header injected by gateway and exposes it through the request
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// context.
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//
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// Backend trusts the header value because the network segment between gateway
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// and backend is the trust boundary (see `ARCHITECTURE.md` §15). The
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// middleware therefore only validates the syntactic shape (UUID) and rejects
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// malformed or absent values with the standard `400 invalid_request` envelope.
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package userid
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import (
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"context"
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"net/http"
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"strings"
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"galaxy/backend/internal/server/httperr"
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"github.com/gin-gonic/gin"
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"github.com/google/uuid"
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)
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// Header is the canonical case-correct header name carrying the trusted user
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// id forwarded by gateway.
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const Header = "X-User-ID"
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// userIDContextKey is the unexported context key used to store the parsed
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// user id. The unexported value type prevents accidental collisions with
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// keys defined in unrelated packages.
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type userIDContextKey struct{}
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// Middleware returns the gin middleware that requires a syntactically valid
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// `X-User-ID` header on every authenticated user request and stores the
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// parsed UUID on the request context.
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func Middleware() gin.HandlerFunc {
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return func(c *gin.Context) {
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raw := strings.TrimSpace(c.GetHeader(Header))
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if raw == "" {
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httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, Header+" header is required")
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return
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}
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userID, err := uuid.Parse(raw)
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if err != nil {
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httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, Header+" header must be a valid UUID")
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return
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}
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c.Request = c.Request.WithContext(WithValue(c.Request.Context(), userID))
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c.Next()
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}
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}
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// FromContext returns the user id stored on ctx by Middleware. The boolean
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// reports whether a value was found.
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func FromContext(ctx context.Context) (uuid.UUID, bool) {
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if ctx == nil {
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return uuid.Nil, false
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}
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value, ok := ctx.Value(userIDContextKey{}).(uuid.UUID)
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if !ok {
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return uuid.Nil, false
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}
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return value, true
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}
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// WithValue stores userID on ctx under the package-private context key.
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// Exposed for tests that need to build a context outside the middleware.
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func WithValue(ctx context.Context, userID uuid.UUID) context.Context {
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return context.WithValue(ctx, userIDContextKey{}, userID)
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}
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