3 * @file src/Util/JsonLD.php
5 namespace Friendica\Util;
7 use Friendica\Core\Cache;
8 use Friendica\Core\Logger;
12 * @brief This class contain methods to work with JsonLD data
17 * @brief Loader for LD-JSON validation
21 * @return mixed the loaded data
22 * @throws \JsonLdException
24 public static function documentLoader($url)
28 $x = debug_backtrace();
31 if ($n['function'] === __FUNCTION__) {
38 Logger::error('jsonld bomb detected at: ' . $url);
42 $result = Cache::get('documentLoader:' . $url);
43 if (!is_null($result)) {
47 $data = jsonld_default_document_loader($url);
48 Cache::set('documentLoader:' . $url, $data, Cache::DAY);
53 * @brief Normalises a given JSON array
57 * @return mixed|bool normalized JSON string
60 public static function normalize($json)
62 jsonld_set_document_loader('Friendica\Util\JsonLD::documentLoader');
64 $jsonobj = json_decode(json_encode($json, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
67 $normalized = jsonld_normalize($jsonobj, array('algorithm' => 'URDNA2015', 'format' => 'application/nquads'));
69 catch (Exception $e) {
72 $currentException = $e;
74 $messages[] = $currentException->getMessage();
75 } while($currentException = $currentException->getPrevious());
77 Logger::warning('JsonLD normalize error');
78 Logger::notice('JsonLD normalize error', ['messages' => $messages]);
79 Logger::info('JsonLD normalize error', ['trace' => $e->getTraceAsString()]);
80 Logger::debug('JsonLD normalize error', ['jsonobj' => $jsonobj]);
87 * @brief Compacts a given JSON array
91 * @return array Compacted JSON array
94 public static function compact($json)
96 jsonld_set_document_loader('Friendica\Util\JsonLD::documentLoader');
98 $context = (object)['as' => 'https://www.w3.org/ns/activitystreams#',
99 'w3id' => 'https://w3id.org/security#',
100 'ldp' => (object)['@id' => 'http://www.w3.org/ns/ldp#', '@type' => '@id'],
101 'vcard' => (object)['@id' => 'http://www.w3.org/2006/vcard/ns#', '@type' => '@id'],
102 'dfrn' => (object)['@id' => 'http://purl.org/macgirvin/dfrn/1.0/', '@type' => '@id'],
103 'diaspora' => (object)['@id' => 'https://diasporafoundation.org/ns/', '@type' => '@id'],
104 'ostatus' => (object)['@id' => 'http://ostatus.org#', '@type' => '@id'],
105 'dc' => (object)['@id' => 'http://purl.org/dc/terms/', '@type' => '@id'],
106 'toot' => (object)['@id' => 'http://joinmastodon.org/ns#', '@type' => '@id'],
107 'litepub' => (object)['@id' => 'http://litepub.social/ns#', '@type' => '@id']];
109 // Preparation for adding possibly missing content to the context
110 if (!empty($json['@context']) && is_string($json['@context'])) {
111 $json['@context'] = [$json['@context']];
114 // Workaround for servers with missing context
115 // See issue https://github.com/nextcloud/social/issues/330
116 if (!empty($json['@context']) && is_array($json['@context'])) {
117 $json['@context'][] = 'https://w3id.org/security/v1';
120 // Trying to avoid memory problems with large content fields
121 if (!empty($json['object']['source']['content'])) {
122 $content = $json['object']['source']['content'];
123 $json['object']['source']['content'] = '';
126 $jsonobj = json_decode(json_encode($json, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
129 $compacted = jsonld_compact($jsonobj, $context);
131 catch (Exception $e) {
133 Logger::error('compacting error');
134 // Sooner or later we should log some details as well - but currently this leads to memory issues
135 // Logger::log('compacting error:' . substr(print_r($e, true), 0, 10000), Logger::DEBUG);
138 $json = json_decode(json_encode($compacted, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE), true);
140 if (isset($json['as:object']['as:source']['as:content']) && !empty($content)) {
141 $json['as:object']['as:source']['as:content'] = $content;
148 * @brief Fetches an element array from a JSON array
154 * @return array fetched element
156 public static function fetchElementArray($array, $element, $key = '@id')
162 if (!isset($array[$element])) {
166 // If it isn't an array yet, make it to one
167 if (!is_int(key($array[$element]))) {
168 $array[$element] = [$array[$element]];
173 foreach ($array[$element] as $entry) {
174 if (!is_array($entry)) {
175 $elements[] = $entry;
176 } elseif (isset($entry[$key])) {
177 $elements[] = $entry[$key];
178 } elseif (!empty($entry) || !is_array($entry)) {
179 $elements[] = $entry;
187 * @brief Fetches an element from a JSON array
195 * @return string fetched element
197 public static function fetchElement($array, $element, $key = '@id', $type = null, $type_value = null)
203 if (!isset($array[$element])) {
207 if (!is_array($array[$element])) {
208 return $array[$element];
211 if (is_null($type) || is_null($type_value)) {
212 $element_array = self::fetchElementArray($array, $element, $key);
213 if (is_null($element_array)) {
217 return array_shift($element_array);
220 $element_array = self::fetchElementArray($array, $element);
221 if (is_null($element_array)) {
225 foreach ($element_array as $entry) {
226 if (isset($entry[$key]) && isset($entry[$type]) && ($entry[$type] == $type_value)) {