Merge pull request #22 from batopa/feat/api-proxy-trait

Add API proxy trait

src/Controller/ApiProxyTrait.php

@@ -0,0 +1,276 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * BEdita, API-first content management framework
+ * Copyright 2020 ChannelWeb Srl, Chialab Srl
+ *
+ * This file is part of BEdita: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * See LICENSE.LGPL or <http://gnu.org/licenses/lgpl-3.0.html> for more details.
+ */
+namespace BEdita\WebTools\Controller;
+
+use BEdita\SDK\BEditaClientException;
+use BEdita\WebTools\ApiClientProvider;
+use Cake\Http\Exception\MethodNotAllowedException;
+use Cake\Routing\Router;
+use Cake\Utility\Hash;
+use Cake\View\ViewVarsTrait;
+
+/**
+ * Use this Trait in a controller to directly proxy requests to BE4 API.
+ * The response will be the same of the API itself with links masked.
+ *
+ * You need also to define routing rules configured as (for ApiController)
+ *
+ * ```
+ * $builder->scope('/api', ['_namePrefix' => 'api:'], function (RouteBuilder $builder) {
+ *     $builder->get('/**', ['controller' => 'Api', 'action' => 'get'], 'get');
+ *     $builder->post('/**', ['controller' => 'Api', 'action' => 'post'], 'post');
+ *     // and so on for patch, delete if you want to use it
+ * });
+ * ```
+ */
+trait ApiProxyTrait
+{
+    use ViewVarsTrait;
+
+    /**
+     * An instance of a \Cake\Http\ServerRequest object that contains information about the current request.
+     *
+     * @var \Cake\Http\ServerRequest
+     */
+    protected $request;
+
+    /**
+     * An instance of a Response object that contains information about the impending response.
+     *
+     * @var \Cake\Http\Response
+     */
+    protected $response;
+
+    /**
+     * BEdita4 API client
+     *
+     * @var \BEdita\SDK\BEditaClient
+     */
+    protected $apiClient = null;
+
+    /**
+     * Base URL used for mask links.
+     *
+     * @var string
+     */
+    protected $baseUrl = '';
+
+    /**
+     * {@inheritDoc}
+     */
+    public function initialize(): void
+    {
+        parent::initialize();
+
+        if ($this->apiClient === null) {
+            $this->apiClient = ApiClientProvider::getApiClient();
+        }
+
+        $this->viewBuilder()
+            ->setClassName('Json')
+            ->setOption('serialize', true);
+    }
+
+    /**
+     * Set base URL used for mask links removing trailing slashes.
+     *
+     * @param string $path The path on which build base URL
+     * @return void
+     */
+    protected function setBaseUrl($path): void
+    {
+        $requestPath = $this->request->getPath();
+        $basePath = substr($requestPath, 0, strpos($requestPath, $path));
+        $this->baseUrl = Router::url(rtrim($basePath, '/'), true);
+    }
+
+    /**
+     * Proxy for GET requests to BEdita4 API
+     *
+     * @param string $path The path for API request
+     * @return void
+     */
+    public function get($path = '')
+    {
+        $this->setBaseUrl($path);
+        $this->apiRequest([
+            'method' => 'get',
+            'path' => $path,
+            'query' => $this->request->getQueryParams(),
+        ]);
+    }
+
+    /**
+     * Routes a request to the API handling response and errors.
+     *
+     * `$options` are:
+     * - method => the HTTP request method
+     * - path => a string representing the complete endpoint path
+     * - query => an array of query strings
+     * - body => the body sent
+     * - headers => an array of headers
+     *
+     * @param array $options The request options
+     * @return void
+     */
+    protected function apiRequest(array $options): void
+    {
+        $options += [
+            'method' => '',
+            'path' => '',
+            'query' => null,
+            'body' => null,
+            'headers' => null,
+        ];
+
+        try {
+            switch (strtolower($options['method'])) {
+                case 'get':
+                    $response = $this->apiClient->get($options['path'], $options['query'], $options['headers']);
+                    break;
+                // case 'post':
+                //     $response = $this->apiClient->post($options['path'], $options['body'], $options['headers']);
+                //     break;
+                // case 'patch':
+                //     $response = $this->apiClient->patch($options['path'], $options['body'], $options['headers']);
+                //     break;
+                // case 'delete':
+                //     $response = $this->apiClient->delete($options['path'], $options['body'], $options['headers']);
+                //     break;
+                default:
+                    throw new MethodNotAllowedException();
+            }
+
+            if (empty($response) || !is_array($response)) {
+                return;
+            }
+
+            $response = $this->maskResponseLinks($response);
+            $this->set($response);
+        } catch (\Throwable $e) {
+            $this->handleError($e);
+        }
+    }
+
+    /**
+     * Handle error.
+     * Set error var for view.
+     *
+     * @param \Throwable $error The error thrown.
+     * @return void
+     */
+    protected function handleError(\Throwable $error): void
+    {
+        $status = $error->getCode();
+        if ($status < 100 || $status > 599) {
+            $status = 500;
+        }
+        $this->response = $this->response->withStatus($status);
+        $errorData = [
+            'status' => (string)$status,
+            'title' => $error->getMessage(),
+        ];
+        $this->set('error', $errorData);
+
+        if (!$error instanceof BEditaClientException) {
+            return;
+        }
+
+        $errorAttributes = $error->getAttributes();
+        if (!empty($errorAttributes)) {
+            $this->set('error', $errorAttributes);
+        }
+    }
+
+    /**
+     * Mask links of response to not expose API URL.
+     *
+     * @param array $response The response from API
+     * @return array
+     */
+    protected function maskResponseLinks(array $response): array
+    {
+        $response = $this->maskLinks($response, '$id');
+        $response = $this->maskLinks($response, 'links');
+        $response = $this->maskLinks($response, 'meta.schema');
+
+        if (!empty($response['meta']['resources'])) {
+            $response = $this->maskMultiLinks($response, 'meta.resources', 'href');
+        }
+
+        $data = (array)Hash::get($response, 'data');
+        if (empty($data)) {
+            return $response;
+        }
+
+        if (Hash::numeric(array_keys($data))) {
+            foreach ($data as &$item) {
+                $item = $this->maskLinks($item, 'links');
+                $item = $this->maskMultiLinks($item);
+            }
+            $response['data'] = $data;
+        } else {
+            $response['data']['relationships'] = $this->maskMultiLinks($data);
+        }
+
+        return (array)$response;
+    }
+
+    /**
+     * Mask links across multidimensional array.
+     * By default search for `relationships` and mask their `links`.
+     *
+     * @param array $data The data with links to mask
+     * @param string $path The path to search for
+     * @param string $key The key on which are the links
+     * @return array
+     */
+    protected function maskMultiLinks(array $data, string $path = 'relationships', string $key = 'links'): array
+    {
+        $relationships = Hash::get($data, $path, []);
+        foreach ($relationships as &$rel) {
+            $rel = $this->maskLinks($rel, $key);
+        }
+
+        return Hash::insert($data, $path, $relationships);
+    }
+
+    /**
+     * Mask links found in `$path`
+     *
+     * @param array $data The data with links to mask
+     * @param string $path The path to search for
+     * @return array
+     */
+    protected function maskLinks(array $data, string $path): array
+    {
+        $links = Hash::get($data, $path, []);
+        if (empty($links)) {
+            return $data;
+        }
+
+        if (is_string($links)) {
+            $links = str_replace($this->apiClient->getApiBaseUrl(), $this->baseUrl, $links);
+
+            return Hash::insert($data, $path, $links);
+        }
+
+        foreach ($links as &$link) {
+            $link = str_replace($this->apiClient->getApiBaseUrl(), $this->baseUrl, $link);
+        }
+
+        return Hash::insert($data, $path, $links);
+    }
+}