return json if jsonp has not callback (#1438)

return json if jsonp has not callback

context.go

@@ -695,7 +695,12 @@ func (c *Context) SecureJSON(code int, obj interface{}) {
 // It add 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".
 func (c *Context) JSONP(code int, obj interface{}) {
-	c.Render(code, render.JsonpJSON{Callback: c.DefaultQuery("callback", ""), Data: obj})
+	callback := c.DefaultQuery("callback", "")
+	if callback == "" {
+		c.Render(code, render.JSON{Data: obj})
+	} else {
+		c.Render(code, render.JsonpJSON{Callback: callback, Data: obj})
+	}
 }
 
 // JSON serializes the given struct as JSON into the response body.

context_test.go

@@ -596,6 +596,20 @@ func TestContextRenderJSONP(t *testing.T) {
 	assert.Equal(t, "application/javascript; charset=utf-8", w.HeaderMap.Get("Content-Type"))
 }
 
+// Tests that the response is serialized as JSONP
+// and Content-Type is set to application/json
+func TestContextRenderJSONPWithoutCallback(t *testing.T) {
+	w := httptest.NewRecorder()
+	c, _ := CreateTestContext(w)
+	c.Request, _ = http.NewRequest("GET", "http://example.com", nil)
+
+	c.JSONP(201, H{"foo": "bar"})
+
+	assert.Equal(t, 201, w.Code)
+	assert.Equal(t, "{\"foo\":\"bar\"}", w.Body.String())
+	assert.Equal(t, "application/json; charset=utf-8", w.HeaderMap.Get("Content-Type"))
+}
+
 // Tests that no JSON is rendered if code is 204
 func TestContextRenderNoContentJSON(t *testing.T) {
 	w := httptest.NewRecorder()