Make usage of zend-json fully optional

Adds a new method to `AbstractRestfulController`, `jsonEncode()` which:

- checks for presence of `json_encode()`; if present, uses it to decode the
  provided string.
- checks for presence of `Zend\Json\Json`; if present, uses
  `Zend\Json\Json::decode()` to decode the provided string.
- throws an exception if neither is available

The above is now used by both `processPostData()` and `processBodyContent()`
when parsing JSON.

Removed `zend-json` from the `require-dev` section, and updated its description
in the `suggest` section.

Author: weierophinney

composer.json

@@ -28,7 +28,6 @@
         "zendframework/zend-di": "^2.6",
         "zendframework/zend-filter": "^2.6.1",
         "zendframework/zend-inputfilter": "^2.6",
-        "zendframework/zend-json": "^2.6.1",
         "zendframework/zend-log": "^2.7.1",
         "zendframework/zend-modulemanager": "^2.7.1",
         "zendframework/zend-serializer": "^2.6.1",
@@ -43,7 +42,7 @@
         "zendframework/zend-filter": "Zend\\Filter component",
         "zendframework/zend-http": "Zend\\Http component",
         "zendframework/zend-inputfilter": "Zend\\Inputfilter component",
-        "zendframework/zend-json": "Zend\\Json component",
+        "zendframework/zend-json": "To auto-deserialize JSON body content in AbstractRestfulController extensions, when json_decode is unavailable",
         "zendframework/zend-log": "Zend\\Log component",
         "zendframework/zend-modulemanager": "Zend\\ModuleManager component",
         "zendframework/zend-mvc-console": "zend-mvc-console provides the ability to expose zend-mvc as a console application",

composer.lock

@@ -45,9 +45,23 @@ abstract class AbstractRestfulController extends AbstractController
     protected $identifierName = 'id';
 
     /**
-     * @var int From Zend\Json\Json
+     * Flag to pass to json_decode and/or Zend\Json\Json::decode.
+     *
+     * The flags in Zend\Json\Json::decode are integers, but when evaluated
+     * in a boolean context map to the flag passed as the second parameter
+     * to json_decode(). As such, you can specify either the Zend\Json\Json
+     * constant or the boolean value. By default, starting in v3, we use
+     * the boolean value, and cast to integer if using Zend\Json\Json::decode.
+     *
+     * Default value is boolean true, meaning JSON should be cast to
+     * associative arrays (vs objects).
+     *
+     * Override the value in an extending class to set the default behavior
+     * for your class.
+     *
+     * @var int|bool
      */
-    protected $jsonDecodeType = Json::TYPE_ARRAY;
+    protected $jsonDecodeType = true;
 
     /**
      * Map of custom HTTP methods and their handlers
@@ -444,16 +458,16 @@ public function onDispatch(MvcEvent $e)
      *
      * @param Request $request
      * @return mixed
+     * @throws Exception\DomainException If a JSON request was made, but no
+     *    method for parsing JSON is available.
      */
     public function processPostData(Request $request)
     {
         if ($this->requestHasContentType($request, self::CONTENT_TYPE_JSON)) {
-            $data = Json::decode($request->getContent(), $this->jsonDecodeType);
-        } else {
-            $data = $request->getPost()->toArray();
+            return $this->create($this->jsonDecode($request->getContent()));
         }
 
-        return $this->create($data);
+        return $this->create($request->getPost()->toArray());
     }
 
     /**
@@ -564,14 +578,16 @@ protected function getIdentifier($routeMatch, $request)
      *
      * @param  mixed $request
      * @return object|string|array
+     * @throws Exception\DomainException If a JSON request was made, but no
+     *    method for parsing JSON is available.
      */
     protected function processBodyContent($request)
     {
         $content = $request->getContent();
 
         // JSON content? decode and return it.
         if ($this->requestHasContentType($request, self::CONTENT_TYPE_JSON)) {
-            return Json::decode($content, $this->jsonDecodeType);
+            return $this->jsonDecode($request->getContent());
         }
 
         parse_str($content, $parsedParams);
@@ -585,4 +601,35 @@ protected function processBodyContent($request)
 
         return $parsedParams;
     }
+
+    /**
+     * Decode a JSON string.
+     *
+     * Uses json_decode by default. If that is not available, checks for
+     * availability of Zend\Json\Json, and uses that if present.
+     *
+     * Otherwise, raises an exception.
+     *
+     * Marked protected to allow usage from extending classes.
+     *
+     * @param string
+     * @return mixed
+     * @throws Exception\DomainException if no JSON decoding functionality is
+     *     available.
+     */
+    protected function jsonDecode($string)
+    {
+        if (function_exists('json_decode')) {
+            return json_decode($string, (bool) $this->jsonDecodeType);
+        }
+
+        if (class_exists(Json::class)) {
+            return Json::decode($string, (int) $this->jsonDecodeType);
+        }
+
+        throw new Exception\DomainException(sprintf(
+            'Unable to parse JSON request, due to missing ext/json and/or %s',
+            Json::class
+        ));
+    }
 }