fix: do not cache api (incl. grpc) and http errors (#2088)

* fix: add cache-control headers (no-store, no-cache) on grpc (for grpc-web)

* fix: do not cache api response (incl. grpc) and http errors

internal/api/grpc/server/gateway.go

@@ -134,7 +134,6 @@ func createDialOptions(g Gateway) []grpc.DialOption {
 func addInterceptors(handler http.Handler, g Gateway) http.Handler {
 	handler = http_mw.DefaultMetricsHandler(handler)
 	handler = http_mw.DefaultTelemetryHandler(handler)
-	handler = http_mw.NoCacheInterceptor(handler)
 	if interceptor, ok := g.(grpcGatewayCustomInterceptor); ok {
 		handler = interceptor.GatewayHTTPInterceptor(handler)
 	}

internal/api/grpc/server/middleware/cache_interceptor.go

@@ -0,0 +1,32 @@
+package middleware
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"github.com/caos/logging"
+	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+
+	_ "github.com/caos/zitadel/internal/statik"
+)
+
+func NoCacheInterceptor() grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
+		headers := map[string]string{
+			"cache-control": "no-store",
+			"expires":       time.Now().UTC().Format(http.TimeFormat),
+			"pragma":        "no-cache",
+		}
+		header := metadata.New(headers)
+		for key, value := range headers {
+			header.Append(runtime.MetadataHeaderPrefix+key, value)
+		}
+		err := grpc.SendHeader(ctx, header)
+		logging.Log("MIDDLE-efh41").OnError(err).WithField("req", info.FullMethod).Warn("cannot send cache-control on grpc response")
+		resp, err := handler(ctx, req)
+		return resp, err
+	}
+}

internal/api/grpc/server/server.go

@@ -36,6 +36,7 @@ func CreateServer(verifier *authz.TokenVerifier, authConfig authz.Config, lang l
 				middleware.DefaultTracingServer(),
 				middleware.MetricsHandler(metricTypes, grpc_api.Probes...),
 				middleware.SentryHandler(),
+				middleware.NoCacheInterceptor(),
 				middleware.ErrorHandler(),
 				middleware.AuthorizationInterceptor(verifier, authConfig),
 				middleware.TranslationHandler(lang),

internal/api/http/middleware/cache_interceptor.go

@@ -81,11 +81,29 @@ func AssetsCacheInterceptor(maxAge, sharedMaxAge time.Duration, h http.Handler)
 
 func CacheInterceptorOpts(h http.Handler, cache *Cache) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
-		cache.serializeHeaders(w)
-		h.ServeHTTP(w, req)
+		cachingResponseWriter := &cachingResponseWriter{
+			ResponseWriter: w,
+			Cache:          cache,
+		}
+		h.ServeHTTP(cachingResponseWriter, req)
 	})
 }
 
+type cachingResponseWriter struct {
+	http.ResponseWriter
+	*Cache
+}
+
+func (w *cachingResponseWriter) WriteHeader(code int) {
+	if code >= 400 {
+		NeverCacheOptions.serializeHeaders(w.ResponseWriter)
+		w.ResponseWriter.WriteHeader(code)
+		return
+	}
+	w.Cache.serializeHeaders(w.ResponseWriter)
+	w.ResponseWriter.WriteHeader(code)
+}
+
 func (c *Cache) serializeHeaders(w http.ResponseWriter) {
 	control := make([]string, 0, 6)
 	pragma := false