Initial commit

internal/auth/middleware.go

@@ -0,0 +1,50 @@
+package auth
+
+import (
+	"context"
+	"net/http"
+
+	"logjensticks/internal/db"
+)
+
+const CookieName = "session_token"
+
+type contextKey string
+
+const sessionContextKey contextKey = "session"
+
+// Middleware validates the session cookie on every request. Attach this to
+// any route that requires authentication.
+func Middleware(dbc *db.Client) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			cookie, err := r.Cookie(CookieName)
+			if err != nil {
+				writeUnauthorized(w)
+				return
+			}
+
+			session, err := ValidateSession(r.Context(), dbc, cookie.Value)
+			if err != nil {
+				writeUnauthorized(w)
+				return
+			}
+
+			ctx := context.WithValue(r.Context(), sessionContextKey, session)
+			next.ServeHTTP(w, r.WithContext(ctx))
+		})
+	}
+}
+
+// SessionFromContext retrieves the validated session attached by Middleware.
+// Returns nil if called outside an authenticated route.
+func SessionFromContext(ctx context.Context) *Session {
+	s, _ := ctx.Value(sessionContextKey).(*Session)
+	return s
+}
+
+func writeUnauthorized(w http.ResponseWriter) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusUnauthorized)
+	w.Write([]byte(`{"success":false,"data":null,"error":{"code":"UNAUTHORIZED","message":"authentication required"}}`))
+}