Add ApiPaginationComponent

Author: bcrowe

src/Controller/Component/ApiPaginationComponent.php

@@ -0,0 +1,113 @@
+<?php
+namespace BryanCrowe\ApiPagination\Controller\Component;
+
+use Cake\Controller\Component;
+use Cake\Controller\Controller;
+use Cake\Event\Event;
+
+/**
+ * This is a simple component that injects pagination info into responses when
+ * using CakePHP's PaginatorComponent alongside of CakePHP's JsonView or XmlView
+ * classes.
+ */
+class ApiPaginationComponent extends Component
+{
+    /**
+     * Default config.
+     *
+     * @var array
+     */
+    protected $_defaultConfig = [
+        'key' => 'pagination',
+        'aliases' => [],
+        'visible' => []
+    ];
+
+    /**
+     * Holds the paging information.
+     *
+     * @var array
+     */
+    protected $paging = [];
+
+    /**
+     * Injects the pagination info into the response if the current request is a
+     * JSON or XML request with pagination.
+     *
+     * @param Event $event The Controller.beforeRender event.
+     * @return void
+     */
+    public function beforeRender(Event $event)
+    {
+        $controller = $event->subject();
+
+        if (!$this->isPaginatedApiRequest($controller)) {
+            return;
+        }
+
+        $this->paging = $controller->request->params['paging'][$controller->name];
+
+        if (!empty($this->config('aliases'))) {
+            $this->setAliases();
+        }
+
+        if (!empty($this->config('visible'))) {
+            $this->setVisible();
+        }
+
+        $controller->set($this->config('key'), $this->paging);
+        $controller->viewVars['_serialize'][] = $this->config('key');
+    }
+
+    /**
+     * Aliases the default pagination keys to the new keys that the user defines
+     * in the config.
+     *
+     * @return void
+     */
+    protected function setAliases()
+    {
+        $aliases = $this->config('aliases');
+        foreach ($aliases as $key => $value) {
+            $this->paging[$value] = $this->paging[$key];
+            unset($this->paging[$key]);
+        }
+    }
+
+    /**
+     * Removes any pagination keys that haven't been defined as visible in the
+     * config.
+     *
+     * @return void
+     */
+    protected function setVisible()
+    {
+        $visible = $this->config('visible');
+        foreach ($this->paging as $key => $value) {
+            if (!in_array($key, $visible)) {
+                unset($this->paging[$key]);
+            }
+        }
+    }
+
+    /**
+     * Checks whether the current request is a JSON or XML request with
+     * pagination.
+     *
+     * @param \Cake\Controller\Controller $controller A reference to the
+     *   instantiating controller object
+     * @return bool True if JSON or XML with paging, otherwise false.
+     */
+    protected function isPaginatedApiRequest(Controller $controller)
+    {
+        if (
+            $controller->request->is('json') ||
+            $controller->request->is('xml') &&
+            isset($controller->request->params['paging'])
+        ) {
+            return true;
+        }
+
+        return false;
+    }
+}