src/Util/JsonLD.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Util;
  23
  24 use Friendica\Core\Cache\Enum\Duration;
  25 use Friendica\Core\Logger;
  26 use Exception;
  27 use Friendica\Core\System;
  28 use Friendica\DI;
  29
  30 /**
  31  * This class contain methods to work with JsonLD data
  32  */
  33 class JsonLD
  34 {
  35         /**
  36          * Loader for LD-JSON validation
  37          *
  38          * @param $url
  39          *
  40          * @return mixed the loaded data
  41          * @throws \JsonLdException
  42          */
  43         public static function documentLoader($url)
  44         {
  45                 switch ($url) {
  46                         case 'https://w3id.org/security/v1':
  47                                 $url = DI::baseUrl() . '/static/security-v1.jsonld';
  48                                 break;
  49                         case 'https://w3id.org/identity/v1':
  50                                 $url = DI::baseUrl() . '/static/identity-v1.jsonld';
  51                                 break;
  52                         case 'https://www.w3.org/ns/activitystreams':
  53                                 $url = DI::baseUrl() . '/static/activitystreams.jsonld';
  54                                 break;
  55                         case 'https://funkwhale.audio/ns':
  56                                 $url = DI::baseUrl() . '/static/funkwhale.audio.jsonld';
  57                                 break;
  58                         default:
  59                                 switch (parse_url($url, PHP_URL_PATH)) {
  60                                         case '/schemas/litepub-0.1.jsonld';
  61                                                 $url = DI::baseUrl() . '/static/litepub-0.1.jsonld';
  62                                                 break;
  63                                         case '/apschema/v1.2':
  64                                         case '/apschema/v1.9':
  65                                         case '/apschema/v1.10':
  66                                                         $url = DI::baseUrl() . '/static/apschema.jsonld';
  67                                                 break;
  68                                         default:
  69                                                 Logger::info('Got url', ['url' =>$url]);
  70                                                 break;
  71                                 }
  72                 }
  73
  74                 $recursion = 0;
  75
  76                 $x = debug_backtrace();
  77                 if ($x) {
  78                         foreach ($x as $n) {
  79                                 if ($n['function'] === __FUNCTION__)  {
  80                                         $recursion ++;
  81                                 }
  82                         }
  83                 }
  84
  85                 if ($recursion > 5) {
  86                         Logger::error('jsonld bomb detected at: ' . $url);
  87                         System::exit();
  88                 }
  89
  90                 $result = DI::cache()->get('documentLoader:' . $url);
  91                 if (!is_null($result)) {
  92                         return $result;
  93                 }
  94
  95                 $data = jsonld_default_document_loader($url);
  96                 DI::cache()->set('documentLoader:' . $url, $data, Duration::DAY);
  97                 return $data;
  98         }
  99
 100         /**
 101          * Normalises a given JSON array
 102          *
 103          * @param array $json
 104          *
 105          * @return mixed|bool normalized JSON string
 106          * @throws Exception
 107          */
 108         public static function normalize($json)
 109         {
 110                 jsonld_set_document_loader('Friendica\Util\JsonLD::documentLoader');
 111
 112                 $jsonobj = json_decode(json_encode($json, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
 113
 114                 try {
 115                         $normalized = jsonld_normalize($jsonobj, array('algorithm' => 'URDNA2015', 'format' => 'application/nquads'));
 116                 }
 117                 catch (Exception $e) {
 118                         $normalized = false;
 119                         $messages = [];
 120                         $currentException = $e;
 121                         do {
 122                                 $messages[] = $currentException->getMessage();
 123                         } while($currentException = $currentException->getPrevious());
 124
 125                         Logger::warning('JsonLD normalize error');
 126                         Logger::notice('JsonLD normalize error', ['messages' => $messages]);
 127                         Logger::info('JsonLD normalize error', ['trace' => $e->getTraceAsString()]);
 128                         Logger::debug('JsonLD normalize error', ['jsonobj' => $jsonobj]);
 129                 }
 130
 131                 return $normalized;
 132         }
 133
 134         /**
 135          * Compacts a given JSON array
 136          *
 137          * @param array $json
 138          * @param bool  $logfailed
 139          *
 140          * @return array Compacted JSON array
 141          * @throws Exception
 142          */
 143         public static function compact($json, bool $logfailed = true): array
 144         {
 145                 jsonld_set_document_loader('Friendica\Util\JsonLD::documentLoader');
 146
 147                 $context = (object)['as' => 'https://www.w3.org/ns/activitystreams#',
 148                         'w3id' => 'https://w3id.org/security#',
 149                         'ldp' => (object)['@id' => 'http://www.w3.org/ns/ldp#', '@type' => '@id'],
 150                         'vcard' => (object)['@id' => 'http://www.w3.org/2006/vcard/ns#', '@type' => '@id'],
 151                         'dfrn' => (object)['@id' => 'http://purl.org/macgirvin/dfrn/1.0/', '@type' => '@id'],
 152                         'diaspora' => (object)['@id' => 'https://diasporafoundation.org/ns/', '@type' => '@id'],
 153                         'ostatus' => (object)['@id' => 'http://ostatus.org#', '@type' => '@id'],
 154                         'dc' => (object)['@id' => 'http://purl.org/dc/terms/', '@type' => '@id'],
 155                         'toot' => (object)['@id' => 'http://joinmastodon.org/ns#', '@type' => '@id'],
 156                         'litepub' => (object)['@id' => 'http://litepub.social/ns#', '@type' => '@id'],
 157                         'sc' => (object)['@id' => 'http://schema.org#', '@type' => '@id'],
 158                         'pt' => (object)['@id' => 'https://joinpeertube.org/ns#', '@type' => '@id'],
 159                         'mobilizon' => (object)['@id' => 'https://joinmobilizon.org/ns#', '@type' => '@id'],
 160                         'fedibird' => (object)['@id' => 'http://fedibird.com/ns#', '@type' => '@id'],
 161                         'misskey' => (object)['@id' => 'https://misskey-hub.net/ns#', '@type' => '@id'],
 162                 ];
 163
 164                 $orig_json = $json;
 165
 166                 // Preparation for adding possibly missing content to the context
 167                 if (!empty($json['@context']) && is_string($json['@context'])) {
 168                         $json['@context'] = [$json['@context']];
 169                 }
 170
 171                 if (!empty($json['@context']) && is_array($json['@context'])) {
 172                         // Remove empty entries from the context (a problem with WriteFreely)
 173                         $json['@context'] = array_filter($json['@context']);
 174
 175                         // Workaround for servers with missing context
 176                         // See issue https://github.com/nextcloud/social/issues/330
 177                         if (!in_array('https://w3id.org/security/v1', $json['@context'])) {
 178                                 $json['@context'][] = 'https://w3id.org/security/v1';
 179                         }
 180                 }
 181
 182                 // Bookwyrm transmits "id" fields with "null", which isn't allowed.
 183                 array_walk_recursive($json, function (&$value, $key) {
 184                         if ($key == 'id' && is_null($value)) {
 185                                 $value = '';
 186                         }
 187                 });
 188
 189                 $jsonobj = json_decode(json_encode($json, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
 190
 191                 try {
 192                         $compacted = jsonld_compact($jsonobj, $context);
 193                 }
 194                 catch (Exception $e) {
 195                         $compacted = false;
 196                         Logger::notice('compacting error', ['msg' => $e->getMessage(), 'previous' => $e->getPrevious(), 'line' => $e->getLine()]);
 197                         if ($logfailed && DI::config()->get('debug', 'ap_log_failure')) {
 198                                 $tempfile = tempnam(System::getTempPath(), 'failed-jsonld');
 199                                 file_put_contents($tempfile, json_encode(['json' => $orig_json, 'callstack' => System::callstack(20), 'msg' => $e->getMessage(), 'previous' => $e->getPrevious()], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT));
 200                                 Logger::notice('Failed message stored', ['file' => $tempfile]);
 201                         }
 202                 }
 203
 204                 $json = json_decode(json_encode($compacted, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE), true);
 205
 206                 if ($json === false) {
 207                         Logger::notice('JSON encode->decode failed', ['orig_json' => $orig_json, 'compacted' => $compacted]);
 208                         $json = [];
 209                 }
 210
 211                 return $json;
 212         }
 213
 214         /**
 215          * Fetches an element array from a JSON array
 216          *
 217          * @param $array
 218          * @param $element
 219          * @param $key
 220          *
 221          * @return array fetched element
 222          */
 223         public static function fetchElementArray($array, $element, $key = null, $type = null, $type_value = null)
 224         {
 225                 if (!isset($array[$element])) {
 226                         return null;
 227                 }
 228
 229                 // If it isn't an array yet, make it to one
 230                 if (!is_array($array[$element]) || !is_int(key($array[$element]))) {
 231                         $array[$element] = [$array[$element]];
 232                 }
 233
 234                 $elements = [];
 235
 236                 foreach ($array[$element] as $entry) {
 237                         if (!is_array($entry) || is_null($key)) {
 238                                 $item = $entry;
 239                         } elseif (isset($entry[$key])) {
 240                                 $item = $entry[$key];
 241                         }
 242
 243                         if (isset($item) && (is_null($type) || is_null($type_value) || isset($item[$type]) && $item[$type] == $type_value)) {
 244                                 $elements[] = $item;
 245                         }
 246                 }
 247
 248                 return $elements;
 249         }
 250
 251         /**
 252          * Fetches an element from a JSON array
 253          *
 254          * @param $array
 255          * @param $element
 256          * @param $key
 257          * @param $type
 258          * @param $type_value
 259          *
 260          * @return string fetched element
 261          */
 262         public static function fetchElement($array, $element, $key = '@id', $type = null, $type_value = null)
 263         {
 264                 if (empty($array)) {
 265                         return null;
 266                 }
 267
 268                 if (!isset($array[$element])) {
 269                         return null;
 270                 }
 271
 272                 if (!is_array($array[$element])) {
 273                         return $array[$element];
 274                 }
 275
 276                 if (is_null($type) || is_null($type_value)) {
 277                         $element_array = self::fetchElementArray($array, $element, $key);
 278                         if (is_null($element_array)) {
 279                                 return null;
 280                         }
 281
 282                         return array_shift($element_array);
 283                 }
 284
 285                 $element_array = self::fetchElementArray($array, $element);
 286                 if (is_null($element_array)) {
 287                         return null;
 288                 }
 289
 290                 foreach ($element_array as $entry) {
 291                         if (isset($entry[$key]) && isset($entry[$type]) && ($entry[$type] == $type_value)) {
 292                                 return $entry[$key];
 293                         }
 294                 }
 295
 296                 return null;
 297         }
 298 }