lib/flickrclient.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * Provides {@link flickr_client} class.
  19  *
  20  * @package     core
  21  * @copyright   2017 David Mudrák <david@moodle.com>
  22  * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23  */
  24
  25 defined('MOODLE_INTERNAL') || die();
  26
  27 require_once($CFG->libdir.'/oauthlib.php');
  28
  29 /**
  30  * Simple Flickr API client implementing the features needed by Moodle
  31  *
  32  * @copyright 2017 David Mudrak <david@moodle.com>
  33  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  34  */
  35 class flickr_client extends oauth_helper {
  36
  37     /**
  38      * Base URL for Flickr OAuth 1.0 API calls.
  39      */
  40     const OAUTH_ROOT = 'https://www.flickr.com/services/oauth';
  41
  42     /**
  43      * Base URL for Flickr REST API calls.
  44      */
  45     const REST_ROOT = 'https://api.flickr.com/services/rest';
  46
  47     /**
  48      * Base URL for Flickr Upload API call.
  49      */
  50     const UPLOAD_ROOT = 'https://up.flickr.com/services/upload/';
  51
  52     /**
  53      * Set up OAuth and initialize the client.
  54      *
  55      * The callback URL specified here will override the one specified in the
  56      * auth flow defined at Flickr Services.
  57      *
  58      * @param string $consumerkey
  59      * @param string $consumersecret
  60      * @param moodle_url|string $callbackurl
  61      */
  62     public function __construct($consumerkey, $consumersecret, $callbackurl = '') {
  63         global $CFG;
  64         $version = moodle_major_version();
  65         $useragent = "MoodleSite/$version (+{$CFG->wwwroot})";
  66
  67         parent::__construct([
  68             'api_root' => self::OAUTH_ROOT,
  69             'oauth_consumer_key' => $consumerkey,
  70             'oauth_consumer_secret' => $consumersecret,
  71             'oauth_callback' => $callbackurl,
  72             'http_options' => ['CURLOPT_USERAGENT' => $useragent]
  73         ]);
  74     }
  75
  76     /**
  77      * Temporarily store the request token secret in the session.
  78      *
  79      * The request token secret is returned by the oauth request_token method.
  80      * It needs to be stored in the session before the user is redirected to
  81      * the Flickr to authorize the client. After redirecting back, this secret
  82      * is used for exchanging the request token with the access token.
  83      *
  84      * The identifiers help to avoid collisions between multiple calls to this
  85      * method from different plugins in the same session. They are used as the
  86      * session cache identifiers. Provide an associative array identifying the
  87      * particular method call. At least, the array must contain the 'caller'
  88      * with the caller's component name. Use additional items if needed.
  89      *
  90      * @param array $identifiers Identification of the call
  91      * @param string $secret
  92      */
  93     public function set_request_token_secret(array $identifiers, $secret) {
  94
  95         if (empty($identifiers) || empty($identifiers['caller'])) {
  96             throw new coding_exception('Invalid call identification');
  97         }
  98
  99         $cache = cache::make_from_params(cache_store::MODE_SESSION, 'core', 'flickrclient', $identifiers);
 100         $cache->set('request_token_secret', $secret);
 101     }
 102
 103     /**
 104      * Returns previously stored request token secret.
 105      *
 106      * See {@link self::set_request_token_secret()} for more details on the
 107      * $identifiers argument.
 108      *
 109      * @param array $identifiers Identification of the call
 110      * @return string|bool False on error, string secret otherwise.
 111      */
 112     public function get_request_token_secret(array $identifiers) {
 113
 114         if (empty($identifiers) || empty($identifiers['caller'])) {
 115             throw new coding_exception('Invalid call identification');
 116         }
 117
 118         $cache = cache::make_from_params(cache_store::MODE_SESSION, 'core', 'flickrclient', $identifiers);
 119
 120         return $cache->get('request_token_secret');
 121     }
 122
 123     /**
 124      * Call a Flickr API method.
 125      *
 126      * @param string $function API function name like 'flickr.photos.getSizes' or just 'photos.getSizes'
 127      * @param array $params Additional API call arguments.
 128      * @param string $method HTTP method to use (GET or POST).
 129      * @return object|bool Response as returned by the Flickr or false on invalid authentication
 130      */
 131     public function call($function, array $params = [], $method = 'GET') {
 132
 133         if (strpos($function, 'flickr.') !== 0) {
 134             $function = 'flickr.'.$function;
 135         }
 136
 137         $params['method'] = $function;
 138         $params['format'] = 'json';
 139         $params['nojsoncallback'] = 1;
 140
 141         $rawresponse = $this->request($method, self::REST_ROOT, $params);
 142         $response = json_decode($rawresponse);
 143
 144         if (!is_object($response) || !isset($response->stat)) {
 145             throw new moodle_exception('flickr_api_call_failed', 'core_error', '', $rawresponse);
 146         }
 147
 148         if ($response->stat === 'ok') {
 149             return $response;
 150
 151         } else if ($response->stat === 'fail' && $response->code == 98) {
 152             // Authentication failure, give the caller a chance to re-authenticate.
 153             return false;
 154
 155         } else {
 156             throw new moodle_exception('flickr_api_call_failed', 'core_error', '', $response);
 157         }
 158
 159         return $response;
 160     }
 161
 162     /**
 163      * Return the URL to fetch the given photo from.
 164      *
 165      * Flickr photos are distributed via farm servers staticflickr.com in
 166      * various sizes (resolutions). The method tries to find the source URL of
 167      * the photo in the highest possible resolution. Results are cached so that
 168      * we do not need to query the Flickr API over and over again.
 169      *
 170      * @param string $photoid Flickr photo identifier
 171      * @return string URL
 172      */
 173     public function get_photo_url($photoid) {
 174
 175         $cache = cache::make_from_params(cache_store::MODE_APPLICATION, 'core', 'flickrclient');
 176
 177         $url = $cache->get('photourl_'.$photoid);
 178
 179         if ($url === false) {
 180             $response = $this->call('photos.getSizes', ['photo_id' => $photoid]);
 181             // Sizes are returned from smallest to greatest.
 182             if (!empty($response->sizes->size) && is_array($response->sizes->size)) {
 183                 while ($bestsize = array_pop($response->sizes->size)) {
 184                     if (isset($bestsize->source)) {
 185                         $url = $bestsize->source;
 186                         break;
 187                     }
 188                 }
 189             }
 190         }
 191
 192         if ($url === false) {
 193             throw new repository_exception('cannotdownload', 'repository');
 194
 195         } else {
 196             $cache->set('photourl_'.$photoid, $url);
 197         }
 198
 199         return $url;
 200     }
 201
 202     /**
 203      * Upload a photo from Moodle file pool to Flickr.
 204      *
 205      * Optional meta information are title, description, tags, is_public,
 206      * is_friend, is_family, safety_level, content_type and hidden.
 207      * See {@link https://www.flickr.com/services/api/upload.api.html}.
 208      *
 209      * Upload can't be asynchronous because then the query would not return the
 210      * photo ID which we need to add the photo to a photoset (album)
 211      * eventually.
 212      *
 213      * @param stored_file $photo stored in Moodle file pool
 214      * @param array $meta optional meta information
 215      * @return int|bool photo id, false on authentication failure
 216      */
 217     public function upload(stored_file $photo, array $meta = []) {
 218
 219         $args = [
 220             'title' => isset($meta['title']) ? $meta['title'] : null,
 221             'description' => isset($meta['description']) ? $meta['description'] : null,
 222             'tags' => isset($meta['tags']) ? $meta['tags'] : null,
 223             'is_public' => isset($meta['is_public']) ? $meta['is_public'] : 0,
 224             'is_friend' => isset($meta['is_friend']) ? $meta['is_friend'] : 0,
 225             'is_family' => isset($meta['is_family']) ? $meta['is_family'] : 0,
 226             'safety_level' => isset($meta['safety_level']) ? $meta['safety_level'] : 1,
 227             'content_type' => isset($meta['content_type']) ? $meta['content_type'] : 1,
 228             'hidden' => isset($meta['hidden']) ? $meta['hidden'] : 2,
 229         ];
 230
 231         $this->sign_secret = $this->consumer_secret.'&'.$this->access_token_secret;
 232         $params = $this->prepare_oauth_parameters(self::UPLOAD_ROOT, ['oauth_token' => $this->access_token] + $args, 'POST');
 233
 234         $params['photo'] = $photo;
 235
 236         $response = $this->http->post(self::UPLOAD_ROOT, $params);
 237
 238         // Reset http header and options to prepare for the next request.
 239         $this->reset_state();
 240
 241         if ($response) {
 242             $xml = simplexml_load_string($response);
 243
 244             if ((string)$xml['stat'] === 'ok') {
 245                 return (int)$xml->photoid;
 246
 247             } else if ((string)$xml['stat'] === 'fail' && (int)$xml->err['code'] == 98) {
 248                 // Authentication failure.
 249                 return false;
 250
 251             } else {
 252                 throw new moodle_exception('flickr_upload_failed', 'core_error', '',
 253                     ['code' => (int)$xml->err['code'], 'message' => (string)$xml->err['msg']]);
 254             }
 255
 256         } else {
 257             throw new moodle_exception('flickr_upload_error', 'core_error', '', null, $response);
 258         }
 259     }
 260
 261     /**
 262      * Resets curl state.
 263      *
 264      * @return void
 265      */
 266     public function reset_state(): void {
 267         $this->http->cleanopt();
 268         $this->http->resetHeader();
 269     }
 270 }