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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* Provides {@link flickr_client} class.
*
* @package core
* @copyright 2017 David Mudrák <david@moodle.com>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
require_once($CFG->libdir.'/oauthlib.php');
/**
* Simple Flickr API client implementing the features needed by Moodle
*
* @copyright 2017 David Mudrak <david@moodle.com>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class flickr_client extends oauth_helper {
/**
* Base URL for Flickr OAuth 1.0 API calls.
*/
const OAUTH_ROOT = 'https://www.flickr.com/services/oauth';
/**
* Base URL for Flickr REST API calls.
*/
const REST_ROOT = 'https://api.flickr.com/services/rest';
/**
* Base URL for Flickr Upload API call.
*/
const UPLOAD_ROOT = 'https://up.flickr.com/services/upload/';
/**
* Set up OAuth and initialize the client.
*
* The callback URL specified here will override the one specified in the
* auth flow defined at Flickr Services.
*
* @param string $consumerkey
* @param string $consumersecret
* @param moodle_url|string $callbackurl
*/
public function __construct($consumerkey, $consumersecret, $callbackurl = '') {
global $CFG;
$version = moodle_major_version();
$useragent = "MoodleSite/$version (+{$CFG->wwwroot})";
parent::__construct([
'api_root' => self::OAUTH_ROOT,
'oauth_consumer_key' => $consumerkey,
'oauth_consumer_secret' => $consumersecret,
'oauth_callback' => $callbackurl,
'http_options' => ['CURLOPT_USERAGENT' => $useragent]
]);
}
/**
* Temporarily store the request token secret in the session.
*
* The request token secret is returned by the oauth request_token method.
* It needs to be stored in the session before the user is redirected to
* the Flickr to authorize the client. After redirecting back, this secret
* is used for exchanging the request token with the access token.
*
* The identifiers help to avoid collisions between multiple calls to this
* method from different plugins in the same session. They are used as the
* session cache identifiers. Provide an associative array identifying the
* particular method call. At least, the array must contain the 'caller'
* with the caller's component name. Use additional items if needed.
*
* @param array $identifiers Identification of the call
* @param string $secret
*/
public function set_request_token_secret(array $identifiers, $secret) {
if (empty($identifiers) || empty($identifiers['caller'])) {
throw new coding_exception('Invalid call identification');
}
$cache = cache::make_from_params(cache_store::MODE_SESSION, 'core', 'flickrclient', $identifiers);
$cache->set('request_token_secret', $secret);
}
/**
* Returns previously stored request token secret.
*
* See {@link self::set_request_token_secret()} for more details on the
* $identifiers argument.
*
* @param array $identifiers Identification of the call
* @return string|bool False on error, string secret otherwise.
*/
public function get_request_token_secret(array $identifiers) {
if (empty($identifiers) || empty($identifiers['caller'])) {
throw new coding_exception('Invalid call identification');
}
$cache = cache::make_from_params(cache_store::MODE_SESSION, 'core', 'flickrclient', $identifiers);
return $cache->get('request_token_secret');
}
/**
* Call a Flickr API method.
*
* @param string $function API function name like 'flickr.photos.getSizes' or just 'photos.getSizes'
* @param array $params Additional API call arguments.
* @param string $method HTTP method to use (GET or POST).
* @return object|bool Response as returned by the Flickr or false on invalid authentication
*/
public function call($function, array $params = [], $method = 'GET') {
if (strpos($function, 'flickr.') !== 0) {
$function = 'flickr.'.$function;
}
$params['method'] = $function;
$params['format'] = 'json';
$params['nojsoncallback'] = 1;
$rawresponse = $this->request($method, self::REST_ROOT, $params);
$response = json_decode($rawresponse);
if (!is_object($response) || !isset($response->stat)) {
throw new moodle_exception('flickr_api_call_failed', 'core_error', '', $rawresponse);
}
if ($response->stat === 'ok') {
return $response;
} else if ($response->stat === 'fail' && $response->code == 98) {
// Authentication failure, give the caller a chance to re-authenticate.
return false;
} else {
throw new moodle_exception('flickr_api_call_failed', 'core_error', '', $response);
}
return $response;
}
/**
* Return the URL to fetch the given photo from.
*
* Flickr photos are distributed via farm servers staticflickr.com in
* various sizes (resolutions). The method tries to find the source URL of
* the photo in the highest possible resolution. Results are cached so that
* we do not need to query the Flickr API over and over again.
*
* @param string $photoid Flickr photo identifier
* @return string URL
*/
public function get_photo_url($photoid) {
$cache = cache::make_from_params(cache_store::MODE_APPLICATION, 'core', 'flickrclient');
$url = $cache->get('photourl_'.$photoid);
if ($url === false) {
$response = $this->call('photos.getSizes', ['photo_id' => $photoid]);
// Sizes are returned from smallest to greatest.
if (!empty($response->sizes->size) && is_array($response->sizes->size)) {
while ($bestsize = array_pop($response->sizes->size)) {
if (isset($bestsize->source)) {
$url = $bestsize->source;
break;
}
}
}
}
if ($url === false) {
throw new repository_exception('cannotdownload', 'repository');
} else {
$cache->set('photourl_'.$photoid, $url);
}
return $url;
}
/**
* Upload a photo from Moodle file pool to Flickr.
*
* Optional meta information are title, description, tags, is_public,
* is_friend, is_family, safety_level, content_type and hidden.
* See {@link https://www.flickr.com/services/api/upload.api.html}.
*
* Upload can't be asynchronous because then the query would not return the
* photo ID which we need to add the photo to a photoset (album)
* eventually.
*
* @param stored_file $photo stored in Moodle file pool
* @param array $meta optional meta information
* @return int|bool photo id, false on authentication failure
*/
public function upload(stored_file $photo, array $meta = []) {
$args = [
'title' => isset($meta['title']) ? $meta['title'] : null,
'description' => isset($meta['description']) ? $meta['description'] : null,
'tags' => isset($meta['tags']) ? $meta['tags'] : null,
'is_public' => isset($meta['is_public']) ? $meta['is_public'] : 0,
'is_friend' => isset($meta['is_friend']) ? $meta['is_friend'] : 0,
'is_family' => isset($meta['is_family']) ? $meta['is_family'] : 0,
'safety_level' => isset($meta['safety_level']) ? $meta['safety_level'] : 1,
'content_type' => isset($meta['content_type']) ? $meta['content_type'] : 1,
'hidden' => isset($meta['hidden']) ? $meta['hidden'] : 2,
];
$this->sign_secret = $this->consumer_secret.'&'.$this->access_token_secret;
$params = $this->prepare_oauth_parameters(self::UPLOAD_ROOT, ['oauth_token' => $this->access_token] + $args, 'POST');
$params['photo'] = $photo;
$response = $this->http->post(self::UPLOAD_ROOT, $params);
if ($response) {
$xml = simplexml_load_string($response);
if ((string)$xml['stat'] === 'ok') {
return (int)$xml->photoid;
} else if ((string)$xml['stat'] === 'fail' && (int)$xml->err['code'] == 98) {
// Authentication failure.
return false;
} else {
throw new moodle_exception('flickr_upload_failed', 'core_error', '',
['code' => (int)$xml->err['code'], 'message' => (string)$xml->err['msg']]);
}
} else {
throw new moodle_exception('flickr_upload_error', 'core_error', '', null, $response);
}
}
}