3 files changed, 50 insertions, 0 deletions
diff --git a/api/auth/context.go b/api/auth/context.go
new file mode 100644
index 00000000..17171261
--- /dev/null
+++ b/api/auth/context.go
@@ -0,0 +1,28 @@
+// Package auth contains helpers for managing identities within the GraphQL API.
+package auth
+
+import (
+	"context"
+
+	"github.com/MichaelMure/git-bug/cache"
+	"github.com/MichaelMure/git-bug/entity"
+)
+
+// identityCtxKey is a unique context key, accessible only in this package.
+var identityCtxKey = &struct{}{}
+
+// CtxWithUser attaches an Identity to a context.
+func CtxWithUser(ctx context.Context, userId entity.Id) context.Context {
+	return context.WithValue(ctx, identityCtxKey, userId)
+}
+
+// UserFromCtx retrieves an IdentityCache from the context.
+// If there is no identity in the context, ErrNotAuthenticated is returned.
+// If an error occurs while resolving the identity (e.g. I/O error), then it will be returned.
+func UserFromCtx(ctx context.Context, r *cache.RepoCache) (*cache.IdentityCache, error) {
+	id, ok := ctx.Value(identityCtxKey).(entity.Id)
+	if !ok {
+		return nil, ErrNotAuthenticated
+	}
+	return r.ResolveIdentity(id)
+}
diff --git a/api/auth/errors.go b/api/auth/errors.go
new file mode 100644
index 00000000..9675afbf
--- /dev/null
+++ b/api/auth/errors.go
@@ -0,0 +1,6 @@
+package auth
+
+import "errors"
+
+// ErrNotAuthenticated is returned to the client if the user requests an action requiring authentication, and they are not authenticated.
+var ErrNotAuthenticated = errors.New("not authenticated or read-only")
diff --git a/api/auth/middleware.go b/api/auth/middleware.go
new file mode 100644
index 00000000..d1d654ce
--- /dev/null
+++ b/api/auth/middleware.go
@@ -0,0 +1,16 @@
+package auth
+
+import (
+	"net/http"
+
+	"github.com/MichaelMure/git-bug/entity"
+)
+
+func Middleware(fixedUserId entity.Id) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			ctx := CtxWithUser(r.Context(), fixedUserId)
+			next.ServeHTTP(w, r.WithContext(ctx))
+		})
+	}
+}