replace Flusher interface with http.ResponseController Flush method (#3773)

johnzhanghua · web-flow · commit a87bea8e25c4 · 2025-08-14T00:45:20.000-04:00
Signed-off-by: John Zhang &lt;johnzhanghua@gmail.com&gt;
diff --git a/http/codegen/templates/server_handler_init.go.tpl b/http/codegen/templates/server_handler_init.go.tpl
@@ -117,9 +117,7 @@ func {{ .HandlerInit }}(
 							errhandler(ctx, w, err)
 						}
 					} else {
-						if f, ok := w.(http.Flusher); ok {
-							f.Flush()
-						}
+						http.NewResponseController(w).Flush()
 						panic(http.ErrAbortHandler) // too late to write an error
 					}
 				}
@@ -140,9 +138,7 @@ func {{ .HandlerInit }}(
 				return
 			}
 			if _, err := io.Copy(w, buf); err != nil {
-				if f, ok := w.(http.Flusher); ok {
-					f.Flush()
-				}
+				http.NewResponseController(w).Flush()
 				panic(http.ErrAbortHandler) // too late to write an error
 			}
 		{{- else }}
@@ -255,9 +251,7 @@ func {{ .HandlerInit }}(
 						errhandler(ctx, w, err)
 					}
 				} else {
-					if f, ok := w.(http.Flusher); ok {
-						f.Flush()
-					}
+					http.NewResponseController(w).Flush()
 					panic(http.ErrAbortHandler) // too late to write an error
 				}
 			}
@@ -284,9 +278,7 @@ func {{ .HandlerInit }}(
 	{{- end }}
 	{{- if .Method.SkipResponseBodyEncodeDecode }}
 		if _, err := io.Copy(w, buf); err != nil {
-			if f, ok := w.(http.Flusher); ok {
-				f.Flush()
-			}
+			http.NewResponseController(w).Flush()
 			panic(http.ErrAbortHandler) // too late to write an error
 		}
 	{{- end }}
diff --git a/http/codegen/templates/server_sse.go.tpl b/http/codegen/templates/server_sse.go.tpl
@@ -38,7 +38,7 @@ func (s *{{ .SSE.StructName }}) {{ .SSE.SendWithContextName }}(ctx context.Conte
 	{{- else }}
 	res := v
 	{{- end }}
-	
+
 	{{ if .SSE.IDField }}
 	if id := res.{{ .SSE.IDField }}; id != "" {
 		fmt.Fprintf(s.w, "id: %s\n", id)
@@ -66,10 +66,8 @@ func (s *{{ .SSE.StructName }}) {{ .SSE.SendWithContextName }}(ctx context.Conte
 	{{- end }}
 	fmt.Fprintf(s.w, "data: %s\n\n", data)
 
-	if f, ok := s.w.(http.Flusher); ok {
-		f.Flush()
-	}
-    return nil
+	http.NewResponseController(s.w).Flush()
+	return nil
 }
 
 {{ comment "Close is a no-op for SSE. We keep the method for compatibility with other stream types." }}
diff --git a/http/codegen/testdata/golden/handler_skip response body encode decode.go.golden b/http/codegen/testdata/golden/handler_skip response body encode decode.go.golden
@@ -41,9 +41,7 @@ func NewMethodSkipResponseBodyEncodeDecodeHandler(
 						errhandler(ctx, w, err)
 					}
 				} else {
-					if f, ok := w.(http.Flusher); ok {
-						f.Flush()
-					}
+					http.NewResponseController(w).Flush()
 					panic(http.ErrAbortHandler) // too late to write an error
 				}
 			}
@@ -64,9 +62,7 @@ func NewMethodSkipResponseBodyEncodeDecodeHandler(
 			return
 		}
 		if _, err := io.Copy(w, buf); err != nil {
-			if f, ok := w.(http.Flusher); ok {
-				f.Flush()
-			}
+			http.NewResponseController(w).Flush()
 			panic(http.ErrAbortHandler) // too late to write an error
 		}
 	})
diff --git a/http/codegen/testdata/golden/sse-all-fields.golden b/http/codegen/testdata/golden/sse-all-fields.golden
@@ -55,9 +55,7 @@ func (s *SSEAllFieldsMethodServerStream) SendWithContext(ctx context.Context, v
 	data = string(byts)
 	fmt.Fprintf(s.w, "data: %s\n\n", data)
 
-	if f, ok := s.w.(http.Flusher); ok {
-		f.Flush()
-	}
+	http.NewResponseController(s.w).Flush()
 	return nil
 }
 
diff --git a/http/codegen/testdata/golden/sse-bool.golden b/http/codegen/testdata/golden/sse-bool.golden
@@ -41,9 +41,7 @@ func (s *SSEBoolMethodServerStream) SendWithContext(ctx context.Context, v bool)
 	data = string(byts)
 	fmt.Fprintf(s.w, "data: %s\n\n", data)
 
-	if f, ok := s.w.(http.Flusher); ok {
-		f.Flush()
-	}
+	http.NewResponseController(s.w).Flush()
 	return nil
 }
 
diff --git a/http/codegen/testdata/golden/sse-data-field.golden b/http/codegen/testdata/golden/sse-data-field.golden
@@ -41,9 +41,7 @@ func (s *SSEDataFieldMethodServerStream) SendWithContext(ctx context.Context, v
 	data = dataField
 	fmt.Fprintf(s.w, "data: %s\n\n", data)
 
-	if f, ok := s.w.(http.Flusher); ok {
-		f.Flush()
-	}
+	http.NewResponseController(s.w).Flush()
 	return nil
 }
 
diff --git a/http/codegen/testdata/golden/sse-data-id-field.golden b/http/codegen/testdata/golden/sse-data-id-field.golden
@@ -45,9 +45,7 @@ func (s *SSEDataIDFieldMethodServerStream) SendWithContext(ctx context.Context,
 	data = dataField
 	fmt.Fprintf(s.w, "data: %s\n\n", data)
 
-	if f, ok := s.w.(http.Flusher); ok {
-		f.Flush()
-	}
+	http.NewResponseController(s.w).Flush()
 	return nil
 }
 
diff --git a/http/codegen/testdata/golden/sse-int.golden b/http/codegen/testdata/golden/sse-int.golden
@@ -37,9 +37,7 @@ func (s *SSEIntMethodServerStream) SendWithContext(ctx context.Context, v int) e
 	data = fmt.Sprintf("%d", res)
 	fmt.Fprintf(s.w, "data: %s\n\n", data)
 
-	if f, ok := s.w.(http.Flusher); ok {
-		f.Flush()
-	}
+	http.NewResponseController(s.w).Flush()
 	return nil
 }
 
diff --git a/http/codegen/testdata/golden/sse-object.golden b/http/codegen/testdata/golden/sse-object.golden
@@ -43,9 +43,7 @@ func (s *SSEObjectMethodServerStream) SendWithContext(ctx context.Context, v *ss
 	data = string(byts)
 	fmt.Fprintf(s.w, "data: %s\n\n", data)
 
-	if f, ok := s.w.(http.Flusher); ok {
-		f.Flush()
-	}
+	http.NewResponseController(s.w).Flush()
 	return nil
 }
 
diff --git a/http/codegen/testdata/golden/sse-request-id.golden b/http/codegen/testdata/golden/sse-request-id.golden
@@ -38,9 +38,7 @@ func (s *SSERequestIDMethodServerStream) SendWithContext(ctx context.Context, v
 	data = res
 	fmt.Fprintf(s.w, "data: %s\n\n", data)
 
-	if f, ok := s.w.(http.Flusher); ok {
-		f.Flush()
-	}
+	http.NewResponseController(s.w).Flush()
 	return nil
 }
 
diff --git a/http/codegen/testdata/golden/sse-string.golden b/http/codegen/testdata/golden/sse-string.golden
@@ -38,9 +38,7 @@ func (s *SSEStringMethodServerStream) SendWithContext(ctx context.Context, v str
 	data = res
 	fmt.Fprintf(s.w, "data: %s\n\n", data)
 
-	if f, ok := s.w.(http.Flusher); ok {
-		f.Flush()
-	}
+	http.NewResponseController(s.w).Flush()
 	return nil
 }
 
diff --git a/http/codegen/testdata/handler_init_functions.go b/http/codegen/testdata/handler_init_functions.go
@@ -295,9 +295,7 @@ func NewMethodSkipResponseBodyEncodeDecodeHandler(
 						errhandler(ctx, w, err)
 					}
 				} else {
-					if f, ok := w.(http.Flusher); ok {
-						f.Flush()
-					}
+					http.NewResponseController(w).Flush()
 					panic(http.ErrAbortHandler) // too late to write an error
 				}
 			}
@@ -318,9 +316,7 @@ func NewMethodSkipResponseBodyEncodeDecodeHandler(
 			return
 		}
 		if _, err := io.Copy(w, buf); err != nil {
-			if f, ok := w.(http.Flusher); ok {
-				f.Flush()
-			}
+			http.NewResponseController(w).Flush()
 			panic(http.ErrAbortHandler) // too late to write an error
 		}
 	})
diff --git a/http/middleware/capture.go b/http/middleware/capture.go
@@ -41,12 +41,9 @@ func (w *ResponseCapture) Write(b []byte) (int, error) {
 	return n, err
 }
 
-// Flush implements the http.Flusher interface if the underlying response
-// writer supports it.
+// Flush call http.ResponseController Flush() method
 func (w *ResponseCapture) Flush() {
-	if f, ok := w.ResponseWriter.(http.Flusher); ok {
-		f.Flush()
-	}
+	_ = http.NewResponseController(w.ResponseWriter).Flush()
 }
 
 // Push implements the http.Pusher interface if the underlying response
diff --git a/jsonrpc/codegen/templates/sse_server_stream.go.tpl b/jsonrpc/codegen/templates/sse_server_stream.go.tpl
@@ -6,7 +6,7 @@ type {{ .SSE.StructName }} struct {
 	encoder func(context.Context, http.ResponseWriter) goahttp.Encoder
 	// w is the HTTP response writer
 	w http.ResponseWriter
-	// r is the HTTP request  
+	// r is the HTTP request
 	r *http.Request
 	// requestID is the JSON-RPC request ID for sending final response
 	requestID any
@@ -39,9 +39,7 @@ func (s *{{ lowerInitial .SSE.StructName }}EventWriter) Write(data []byte) (int,
 func (s *{{ lowerInitial .SSE.StructName }}EventWriter) finish() {
 	if s.started {
 		s.w.Write([]byte("\n\n"))
-		if f, ok := s.w.(http.Flusher); ok {
-			f.Flush()
-		}
+		http.NewResponseController(s.w).Flush()
 	}
 }
 
@@ -55,27 +53,27 @@ func (s *{{ .SSE.StructName }}) Send(ctx context.Context, event {{ .ServicePkgNa
 		return fmt.Errorf("stream closed")
 	}
 	s.mu.Unlock()
-	
+
 	{{ comment "Type assert to the specific result type" }}
 	result, ok := event.({{ .SSE.EventTypeRef }})
 	if !ok {
 		return fmt.Errorf("unexpected event type: %T", event)
 	}
-	
+
 	{{- if and .Result (index .Result.Responses 0).ServerBody (index (index .Result.Responses 0).ServerBody 0).Init }}
 	{{ comment "Convert to response body type for proper JSON encoding" }}
 	body := {{ (index (index .Result.Responses 0).ServerBody 0).Init.Name }}(result)
 	{{- else }}
 	body := result
 	{{- end }}
-	
+
 	{{ comment "Send as notification (no ID)" }}
 	message := map[string]any{
 		"jsonrpc": "2.0",
 		"method":  {{ printf "%q" .Method.Name }},
 		"params":  body,
 	}
-	
+
 	return s.sendSSEEvent("notification", message)
 }
 
@@ -91,13 +89,13 @@ func (s *{{ .SSE.StructName }}) SendAndClose(ctx context.Context, event {{ .Serv
 	}
 	s.closed = true
 	s.mu.Unlock()
-	
+
 	{{ comment "Type assert to the specific result type" }}
 	result, ok := event.({{ .SSE.EventTypeRef }})
 	if !ok {
 		return fmt.Errorf("unexpected event type: %T", event)
 	}
-	
+
 	{{ comment "Determine the ID to use for the response" }}
 	var id any = s.requestID
 	{{- if .Result.IDAttribute }}
@@ -117,21 +115,21 @@ func (s *{{ .SSE.StructName }}) SendAndClose(ctx context.Context, event {{ .Serv
 	}
 		{{- end }}
 	{{- end }}
-	
+
 	{{- if and .Result (index .Result.Responses 0).ServerBody (index (index .Result.Responses 0).ServerBody 0).Init }}
 	{{ comment "Convert to response body type for proper JSON encoding" }}
 	body := {{ (index (index .Result.Responses 0).ServerBody 0).Init.Name }}(result)
 	{{- else }}
 	body := result
 	{{- end }}
-	
+
 	{{ comment "Send as response with ID" }}
 	message := map[string]any{
 		"jsonrpc": "2.0",
 		"id":      id,
 		"result":  body,
 	}
-	
+
 	return s.sendSSEEvent("response", message)
 }
 
@@ -189,12 +187,12 @@ func (s *{{ .SSE.StructName }}) sendSSEEvent(eventType string, v any) error {
 
 	// Create SSE event writer that wraps the response writer
 	ew := &{{ lowerInitial .SSE.StructName }}EventWriter{w: s.w, eventType: eventType}
-	
+
 	// Create encoder with the event writer and encode the value
 	err := s.encoder(context.Background(), ew).Encode(v)
-	
+
 	// Finish the SSE event (adds newlines and flushes)
 	ew.finish()
-	
+
 	return err
 }
diff --git a/jsonrpc/codegen/templates/sse_server_stream_impl.go.tpl b/jsonrpc/codegen/templates/sse_server_stream_impl.go.tpl
diff --git a/jsonrpc/codegen/testdata/golden/jsonrpc-sse-object.golden b/jsonrpc/codegen/testdata/golden/jsonrpc-sse-object.golden
diff --git a/jsonrpc/codegen/testdata/golden/jsonrpc-sse-string.golden b/jsonrpc/codegen/testdata/golden/jsonrpc-sse-string.golden

Original file line number	Diff line number	Diff line change
`@@ -117,9 +117,7 @@ func {{ .HandlerInit }}(`
`117`	`117`	`errhandler(ctx, w, err)`
`118`	`118`	`}`
`119`	`119`	`} else {`
`120`		`- if f, ok := w.(http.Flusher); ok {`
`121`		`- f.Flush()`
`122`		`- }`
	`120`	`+ http.NewResponseController(w).Flush()`
`123`	`121`	`panic(http.ErrAbortHandler) // too late to write an error`
`124`	`122`	`}`
`125`	`123`	`}`
`@@ -140,9 +138,7 @@ func {{ .HandlerInit }}(`
`140`	`138`	`return`
`141`	`139`	`}`
`142`	`140`	`if _, err := io.Copy(w, buf); err != nil {`
`143`		`- if f, ok := w.(http.Flusher); ok {`
`144`		`- f.Flush()`
`145`		`- }`
	`141`	`+ http.NewResponseController(w).Flush()`
`146`	`142`	`panic(http.ErrAbortHandler) // too late to write an error`
`147`	`143`	`}`
`148`	`144`	`{{- else }}`
`@@ -255,9 +251,7 @@ func {{ .HandlerInit }}(`
`255`	`251`	`errhandler(ctx, w, err)`
`256`	`252`	`}`
`257`	`253`	`} else {`
`258`		`- if f, ok := w.(http.Flusher); ok {`
`259`		`- f.Flush()`
`260`		`- }`
	`254`	`+ http.NewResponseController(w).Flush()`
`261`	`255`	`panic(http.ErrAbortHandler) // too late to write an error`
`262`	`256`	`}`
`263`	`257`	`}`
`@@ -284,9 +278,7 @@ func {{ .HandlerInit }}(`
`284`	`278`	`{{- end }}`
`285`	`279`	`{{- if .Method.SkipResponseBodyEncodeDecode }}`
`286`	`280`	`if _, err := io.Copy(w, buf); err != nil {`
`287`		`- if f, ok := w.(http.Flusher); ok {`
`288`		`- f.Flush()`
`289`		`- }`
	`281`	`+ http.NewResponseController(w).Flush()`
`290`	`282`	`panic(http.ErrAbortHandler) // too late to write an error`
`291`	`283`	`}`
`292`	`284`	`{{- end }}`
Original file line number	Diff line number	Diff line change
`@@ -41,9 +41,7 @@ func NewMethodSkipResponseBodyEncodeDecodeHandler(`
`41`	`41`	`errhandler(ctx, w, err)`
`42`	`42`	`}`
`43`	`43`	`} else {`
`44`		`- if f, ok := w.(http.Flusher); ok {`
`45`		`- f.Flush()`
`46`		`- }`
	`44`	`+ http.NewResponseController(w).Flush()`
`47`	`45`	`panic(http.ErrAbortHandler) // too late to write an error`
`48`	`46`	`}`
`49`	`47`	`}`
`@@ -64,9 +62,7 @@ func NewMethodSkipResponseBodyEncodeDecodeHandler(`
`64`	`62`	`return`
`65`	`63`	`}`
`66`	`64`	`if _, err := io.Copy(w, buf); err != nil {`
`67`		`- if f, ok := w.(http.Flusher); ok {`
`68`		`- f.Flush()`
`69`		`- }`
	`65`	`+ http.NewResponseController(w).Flush()`
`70`	`66`	`panic(http.ErrAbortHandler) // too late to write an error`
`71`	`67`	`}`
`72`	`68`	`})`
Original file line number	Diff line number	Diff line change
`@@ -55,9 +55,7 @@ func (s *SSEAllFieldsMethodServerStream) SendWithContext(ctx context.Context, v`
`55`	`55`	`data = string(byts)`
`56`	`56`	`fmt.Fprintf(s.w, "data: %s\n\n", data)`
`57`	`57`
`58`		`- if f, ok := s.w.(http.Flusher); ok {`
`59`		`- f.Flush()`
`60`		`- }`
	`58`	`+ http.NewResponseController(s.w).Flush()`
`61`	`59`	`return nil`
`62`	`60`	`}`
`63`	`61`
Original file line number	Diff line number	Diff line change
`@@ -41,9 +41,7 @@ func (s *SSEBoolMethodServerStream) SendWithContext(ctx context.Context, v bool)`
`41`	`41`	`data = string(byts)`
`42`	`42`	`fmt.Fprintf(s.w, "data: %s\n\n", data)`
`43`	`43`
`44`		`- if f, ok := s.w.(http.Flusher); ok {`
`45`		`- f.Flush()`
`46`		`- }`
	`44`	`+ http.NewResponseController(s.w).Flush()`
`47`	`45`	`return nil`
`48`	`46`	`}`
`49`	`47`
Original file line number	Diff line number	Diff line change
`@@ -41,9 +41,7 @@ func (s *SSEDataFieldMethodServerStream) SendWithContext(ctx context.Context, v`
`41`	`41`	`data = dataField`
`42`	`42`	`fmt.Fprintf(s.w, "data: %s\n\n", data)`
`43`	`43`
`44`		`- if f, ok := s.w.(http.Flusher); ok {`
`45`		`- f.Flush()`
`46`		`- }`
	`44`	`+ http.NewResponseController(s.w).Flush()`
`47`	`45`	`return nil`
`48`	`46`	`}`
`49`	`47`
Original file line number	Diff line number	Diff line change
`@@ -45,9 +45,7 @@ func (s *SSEDataIDFieldMethodServerStream) SendWithContext(ctx context.Context,`
`45`	`45`	`data = dataField`
`46`	`46`	`fmt.Fprintf(s.w, "data: %s\n\n", data)`
`47`	`47`
`48`		`- if f, ok := s.w.(http.Flusher); ok {`
`49`		`- f.Flush()`
`50`		`- }`
	`48`	`+ http.NewResponseController(s.w).Flush()`
`51`	`49`	`return nil`
`52`	`50`	`}`
`53`	`51`
Original file line number	Diff line number	Diff line change
`@@ -37,9 +37,7 @@ func (s *SSEIntMethodServerStream) SendWithContext(ctx context.Context, v int) e`
`37`	`37`	`data = fmt.Sprintf("%d", res)`
`38`	`38`	`fmt.Fprintf(s.w, "data: %s\n\n", data)`
`39`	`39`
`40`		`- if f, ok := s.w.(http.Flusher); ok {`
`41`		`- f.Flush()`
`42`		`- }`
	`40`	`+ http.NewResponseController(s.w).Flush()`
`43`	`41`	`return nil`
`44`	`42`	`}`
`45`	`43`
Original file line number	Diff line number	Diff line change
`@@ -43,9 +43,7 @@ func (s SSEObjectMethodServerStream) SendWithContext(ctx context.Context, v ss`
`43`	`43`	`data = string(byts)`
`44`	`44`	`fmt.Fprintf(s.w, "data: %s\n\n", data)`
`45`	`45`
`46`		`- if f, ok := s.w.(http.Flusher); ok {`
`47`		`- f.Flush()`
`48`		`- }`
	`46`	`+ http.NewResponseController(s.w).Flush()`
`49`	`47`	`return nil`
`50`	`48`	`}`
`51`	`49`
Original file line number	Diff line number	Diff line change
`@@ -38,9 +38,7 @@ func (s *SSERequestIDMethodServerStream) SendWithContext(ctx context.Context, v`
`38`	`38`	`data = res`
`39`	`39`	`fmt.Fprintf(s.w, "data: %s\n\n", data)`
`40`	`40`
`41`		`- if f, ok := s.w.(http.Flusher); ok {`
`42`		`- f.Flush()`
`43`		`- }`
	`41`	`+ http.NewResponseController(s.w).Flush()`
`44`	`42`	`return nil`
`45`	`43`	`}`
`46`	`44`