WIP: make it work with older versions

middleware/body_dump.go

@@ -99,14 +99,14 @@ func (w *bodyDumpResponseWriter) Write(b []byte) (int, error) {
 }
 
 func (w *bodyDumpResponseWriter) Flush() {
-	err := http.NewResponseController(w.ResponseWriter).Flush()
+	err := responseControllerFlush(w.ResponseWriter)
 	if err != nil && errors.Is(err, http.ErrNotSupported) {
 		panic(errors.New("response writer flushing is not supported"))
 	}
 }
 
 func (w *bodyDumpResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-	return http.NewResponseController(w.ResponseWriter).Hijack()
+	return responseControllerHijack(w.ResponseWriter)
 }
 
 func (w *bodyDumpResponseWriter) Unwrap() http.ResponseWriter {

middleware/compress.go

@@ -191,15 +191,15 @@ func (w *gzipResponseWriter) Flush() {
 	}
 
 	w.Writer.(*gzip.Writer).Flush()
-	http.NewResponseController(w.ResponseWriter).Flush()
+	_ = responseControllerFlush(w.ResponseWriter)
 }
 
 func (w *gzipResponseWriter) Unwrap() http.ResponseWriter {
 	return w.ResponseWriter
 }
 
 func (w *gzipResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-	return http.NewResponseController(w.ResponseWriter).Hijack()
+	return responseControllerHijack(w.ResponseWriter)
 }
 
 func (w *gzipResponseWriter) Push(target string, opts *http.PushOptions) error {

middleware/responsecontroller_1.19.go

@@ -0,0 +1,41 @@
+//go:build !go1.20
+
+package middleware
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"net/http"
+)
+
+// TODO: remove when Go 1.23 is released and we do not support 1.19 anymore
+func responseControllerFlush(rw http.ResponseWriter) error {
+	for {
+		switch t := rw.(type) {
+		case interface{ FlushError() error }:
+			return t.FlushError()
+		case http.Flusher:
+			t.Flush()
+			return nil
+		case interface{ Unwrap() http.ResponseWriter }:
+			rw = t.Unwrap()
+		default:
+			return fmt.Errorf("%w", http.ErrNotSupported)
+		}
+	}
+}
+
+// TODO: remove when Go 1.23 is released and we do not support 1.19 anymore
+func responseControllerHijack(rw http.ResponseWriter) (net.Conn, *bufio.ReadWriter, error) {
+	for {
+		switch t := rw.(type) {
+		case http.Hijacker:
+			return t.Hijack()
+		case interface{ Unwrap() http.ResponseWriter }:
+			rw = t.Unwrap()
+		default:
+			return nil, nil, fmt.Errorf("%w", http.ErrNotSupported)
+		}
+	}
+}

middleware/responsecontroller_1.20.go

@@ -0,0 +1,17 @@
+//go:build go1.20
+
+package middleware
+
+import (
+	"bufio"
+	"net"
+	"net/http"
+)
+
+func responseControllerFlush(rw http.ResponseWriter) error {
+	return http.NewResponseController(rw).Flush()
+}
+
+func responseControllerHijack(rw http.ResponseWriter) (net.Conn, *bufio.ReadWriter, error) {
+	return http.NewResponseController(rw).Hijack()
+}