Merge a14cf7c08dc37b7f9308248928aa3b16307f3c2f into 915e4c90d28ec4cffc6eb146e208ab5a65eac772

context.go

@@ -1165,13 +1165,10 @@ func (c *Context) SecureJSON(code int, obj any) {
 // JSONP serializes the given struct as JSON into the response body.
 // It adds padding to response body to request data from a server residing in a different domain than the client.
 // It also sets the Content-Type as "application/javascript".
+//
+// When the callback parameter is empty, it behaves equivalently to Context.JSON.
 func (c *Context) JSONP(code int, obj any) {
-	callback := c.DefaultQuery("callback", "")
-	if callback == "" {
-		c.Render(code, render.JSON{Data: obj})
-		return
-	}
-	c.Render(code, render.JsonpJSON{Callback: callback, Data: obj})
+	c.Render(code, render.JsonpJSON{Callback: c.Query("callback"), Data: obj})
 }
 
 // JSON serializes the given struct as JSON into the response body.

context_test.go

@@ -1910,7 +1910,7 @@ func TestContextClientIP(t *testing.T) {
 	resetContextForClientIPTests(c)
 
 	// IPv6 support
-	c.Request.RemoteAddr = "[::1]:12345"
+	c.Request.RemoteAddr = fmt.Sprintf("[%s]:12345", localhostIPv6)
 	assert.Equal(t, "20.20.20.20", c.ClientIP())
 
 	resetContextForClientIPTests(c)
@@ -3212,7 +3212,7 @@ func TestContextCopyShouldNotCancel(t *testing.T) {
 	}()
 
 	addr := strings.Split(l.Addr().String(), ":")
-	res, err := http.Get(fmt.Sprintf("http://127.0.0.1:%s/", addr[len(addr)-1]))
+	res, err := http.Get(fmt.Sprintf("http://%s:%s/", localhostIP, addr[len(addr)-1]))
 	if err != nil {
 		t.Error(fmt.Errorf("request error: %w", err))
 		return

gin_test.go

@@ -83,7 +83,7 @@ func TestLoadHTMLGlobDebugMode(t *testing.T) {
 }
 
 func TestH2c(t *testing.T) {
-	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	ln, err := net.Listen("tcp", localhostIP+":0")
 	if err != nil {
 		t.Error(err)
 	}

render/json.go

@@ -115,14 +115,14 @@ func (r SecureJSON) WriteContentType(w http.ResponseWriter) {
 
 // Render (JsonpJSON) marshals the given interface object and writes it and its callback with custom ContentType.
 func (r JsonpJSON) Render(w http.ResponseWriter) (err error) {
-	r.WriteContentType(w)
-	ret, err := json.API.Marshal(r.Data)
-	if err != nil {
-		return err
+	if r.Callback == "" {
+		return WriteJSON(w, r.Data)
 	}
 
-	if r.Callback == "" {
-		_, err = w.Write(ret)
+	r.WriteContentType(w)
+
+	ret, err := json.API.Marshal(r.Data)
+	if err != nil {
 		return err
 	}
 

render/render_test.go

@@ -183,19 +183,28 @@ func TestRenderJsonpJSONError(t *testing.T) {
 	assert.Equal(t, `write "`+`);`+`" error`, err.Error())
 }
 
-func TestRenderJsonpJSONError2(t *testing.T) {
+func TestRenderJsonpJSONWithEmptyCallback(t *testing.T) {
 	w := httptest.NewRecorder()
 	data := map[string]any{
 		"foo": "bar",
+		"num": 42,
+		"nested": map[string]any{
+			"key": "value",
+		},
 	}
-	(JsonpJSON{"", data}).WriteContentType(w)
-	assert.Equal(t, "application/javascript; charset=utf-8", w.Header().Get("Content-Type"))
 
-	e := (JsonpJSON{"", data}).Render(w)
-	require.NoError(t, e)
+	err := (JsonpJSON{Callback: "", Data: data}).Render(w)
 
-	assert.JSONEq(t, "{\"foo\":\"bar\"}", w.Body.String())
-	assert.Equal(t, "application/javascript; charset=utf-8", w.Header().Get("Content-Type"))
+	require.NoError(t, err)
+
+	// Verify Content-Type is set to jsonContentType when callback is empty
+	assert.Equal(t, "application/json; charset=utf-8", w.Header().Get("Content-Type"))
+
+	renderData, err := json.API.Marshal(data)
+	require.NoError(t, err)
+
+	// Verify body contains correct JSON data
+	assert.JSONEq(t, string(renderData), w.Body.String())
 }
 
 func TestRenderJsonpJSONFail(t *testing.T) {

utils.go

@@ -19,6 +19,12 @@ import (
 // BindKey indicates a default bind key.
 const BindKey = "_gin-gonic/gin/bindkey"
 
+// localhostIP indicates the default localhost IP address.
+const localhostIP = "127.0.0.1"
+
+// localhostIPv6 indicates the default localhost IPv6 address.
+const localhostIPv6 = "::1"
+
 // Bind is a helper function for given interface object and returns a Gin middleware.
 func Bind(val any) HandlerFunc {
 	value := reflect.ValueOf(val)