Also allow success to go skip rendering.

docs/Component/Ajax.md

@@ -106,6 +106,34 @@ The nice bonus is the auto-fallback: The controller and all deleting works norma
 
 A live example can be found in the [Sandbox](https://sandbox.dereuromark.de/sandbox/ajax-examples/table).
 
+### Simple boolean response
+
+In cases like "edit in place" you often just need a basic AJAX response as boolean YES/NO, maybe with an error message on top.
+Since we ideally always return a 200 OK response, we need a different way of signaling the frontend if the operation was successful.
+
+Here you can simplify it using the special "error"/"success" keys that auto-format the reponse as JSON:
+```php
+$this->request->allowMethod('post');
+
+$value = $this->request->getData('value');
+if (!$this->process($value)) {
+    $error = 'Didnt work out!';
+    $this->set(compact('error'));
+} else {
+    $success = true; // Or a text like 'You did it!'
+    $this->set(compact('success'));
+}
+```
+
+In the case of x-editable as "edit in place" JS all you need is to check for the error message:
+```js
+success: function(response, newValue) {
+    if (response.error) {
+        return response.error;  //msg will be shown in editable form
+    }
+}
+```
+
 ## Configs
 
 - 'autoDetect' => true // Detect AJAX automatically, regardless of the extension

src/View/AjaxView.php

@@ -89,7 +89,7 @@ public function __construct(
 	 * The rendered content will be part of the JSON response object and
 	 * can be accessed via response.content in JavaScript.
 	 *
-	 * If an error has been set, the rendering will be skipped.
+	 * If an error or success has been set, the rendering will be skipped.
 	 *
 	 * @param string|null $view The view being rendered.
 	 * @param string|null $layout The layout being rendered.
@@ -98,13 +98,18 @@ public function __construct(
 	public function render($view = null, $layout = null) {
 		$dataToSerialize = [
 			'error' => null,
+			'success' => null,
 			'content' => null,
 		];
 
-		if (!empty($this->viewVars['error'])) {
+		if (isset($this->viewVars['error'])) {
 			$dataToSerialize['error'] = $this->viewVars['error'];
 			$view = false;
 		}
+		if (isset($this->viewVars['success'])) {
+			$dataToSerialize['success'] = $this->viewVars['success'];
+			$view = false;
+		}
 
 		if ($view !== false && !isset($this->viewVars['_redirect']) && $this->_getViewFileName($view)) {
 			$dataToSerialize['content'] = parent::render($view, $layout);

tests/TestCase/Middleware/AjaxMiddlewareTest.php

@@ -113,6 +113,7 @@ public function testDefaultsRender() {
 
 		$expected = [
 			'error' => null,
+			'success' => null,
 			'content' => 'My Ajax Index Test ctp',
 			'_message' => $expected,
 		];
@@ -237,6 +238,7 @@ public function testActions() {
 
 		$expected = [
 			'error' => null,
+			'success' => null,
 			'content' => 'My Ajax Index Test ctp',
 			'_message' => null,
 		];
@@ -297,6 +299,7 @@ public function testSetVars() {
 
 		$expected = [
 			'error' => null,
+			'success' => null,
 			'content' => $this->Controller->viewVars['content'],
 			'_message' => null,
 		];

tests/TestCase/View/AjaxViewTest.php

@@ -55,7 +55,7 @@ public function testSerialize() {
 
 		$response = $View->response;
 		$this->assertSame('application/json', $response->getType());
-		$expected = ['error' => null, 'content' => null, 'items' => $items];
+		$expected = ['error' => null, 'success' => null, 'content' => null, 'items' => $items];
 		$expected = json_encode($expected);
 		$this->assertTextEquals($expected, $result);
 	}
@@ -77,7 +77,7 @@ public function testRenderWithSerialize() {
 
 		$response = $View->response;
 		$this->assertSame('application/json', $response->getType());
-		$expected = ['error' => null, 'content' => 'My Ajax Index Test ctp', 'items' => $items];
+		$expected = ['error' => null, 'success' => null, 'content' => 'My Ajax Index Test ctp', 'items' => $items];
 		$expected = json_encode($expected);
 		$this->assertTextEquals($expected, $result);
 	}
@@ -104,7 +104,7 @@ public function testSerializeSetTrue() {
 
 		$response = $View->response;
 		$this->assertSame('application/json', $response->getType());
-		$expected = ['error' => null, 'content' => null, 'items' => $items, 'multiple' => $multiple];
+		$expected = ['error' => null, 'success' => null, 'content' => null, 'items' => $items, 'multiple' => $multiple];
 		$expected = json_encode($expected);
 		$this->assertTextEquals($expected, $result);
 	}
@@ -126,7 +126,7 @@ public function testError() {
 
 		$response = $View->response;
 		$this->assertSame('application/json', $response->getType());
-		$expected = ['error' => 'Some message', 'content' => null, 'items' => $items];
+		$expected = ['error' => 'Some message', 'success' => null, 'content' => null, 'items' => $items];
 		$expected = json_encode($expected);
 		$this->assertTextEquals($expected, $result);
 	}
@@ -147,7 +147,7 @@ public function testWithoutSubdir() {
 
 		$response = $View->response;
 		$this->assertSame('application/json', $response->getType());
-		$expected = ['error' => null, 'content' => 'My Index Test ctp'];
+		$expected = ['error' => null, 'success' => null, 'content' => 'My Index Test ctp'];
 		$expected = json_encode($expected);
 		$this->assertTextEquals($expected, $result);
 	}