feat(transport/http):add StatusCoder to support overriding http status code

transport/http/codec.go

@@ -45,6 +45,9 @@ func DefaultResponseEncoder(w http.ResponseWriter, r *http.Request, v interface{
 		return err
 	}
 	w.Header().Set("Content-Type", httputil.ContentType(codec.Name()))
+	if code, ok := v.(StatusCoder); ok {
+		w.WriteHeader(code.StatusCode())
+	}
 	_, err = w.Write(data)
 	if err != nil {
 		return err
@@ -76,3 +79,9 @@ func CodecForRequest(r *http.Request, name string) (encoding.Codec, bool) {
 	}
 	return encoding.GetCodec("json"), false
 }
+
+// StatusCoder is checked by DefaultResponseEncoder. If a response value implements
+// StatusCoder, the StatusCode will be used to set http status code.
+type StatusCoder interface {
+	StatusCode() int
+}

transport/http/codec_test.go

@@ -52,11 +52,21 @@ func (w *mockResponseWriter) WriteHeader(statusCode int) {
 	w.StatusCode = statusCode
 }
 
-type dataWithStatusCode struct {
+type respData struct {
 	A string `json:"a"`
 	B int64  `json:"b"`
 }
 
+type respDataWithStatusCode struct {
+	A     string `json:"a"`
+	B     int64  `json:"b"`
+	sCode int
+}
+
+func (r *respDataWithStatusCode) StatusCode() int {
+	return r.sCode
+}
+
 func TestDefaultResponseEncoder(t *testing.T) {
 	w := &mockResponseWriter{StatusCode: 200, header: make(nethttp.Header)}
 	req1 := &nethttp.Request{
@@ -64,7 +74,7 @@ func TestDefaultResponseEncoder(t *testing.T) {
 	}
 	req1.Header.Set("Content-Type", "application/json")
 
-	v1 := &dataWithStatusCode{A: "1", B: 2}
+	v1 := &respData{A: "1", B: 2}
 	err := DefaultResponseEncoder(w, req1, v1)
 	if err != nil {
 		t.Errorf("expected no error, got %v", err)
@@ -129,3 +139,26 @@ func TestCodecForRequest(t *testing.T) {
 		t.Errorf("expected %v, got %v", "json", c.Name())
 	}
 }
+
+func TestDefaultResponseEncoderWithStatusCoder(t *testing.T) {
+	w := &mockResponseWriter{StatusCode: 200, header: make(nethttp.Header)}
+	req1 := &nethttp.Request{
+		Header: make(nethttp.Header),
+	}
+	req1.Header.Set("Content-Type", "application/json")
+	cusStatusCode := 201
+	v1 := &respDataWithStatusCode{A: "1", B: 2, sCode: cusStatusCode}
+	err := DefaultResponseEncoder(w, req1, v1)
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+	if !reflect.DeepEqual("application/json", w.Header().Get("Content-Type")) {
+		t.Errorf("expected %v, got %v", "application/json", w.Header().Get("Content-Type"))
+	}
+	if !reflect.DeepEqual(cusStatusCode, w.StatusCode) {
+		t.Errorf("expected %v, got %v", cusStatusCode, w.StatusCode)
+	}
+	if w.Data == nil {
+		t.Errorf("expected not nil, got %v", w.Data)
+	}
+}