253 lines
6.8 KiB
PHP
253 lines
6.8 KiB
PHP
<?php
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/**
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* @copyright Copyright (C) 2020, Friendica
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*
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* @license GNU AGPL version 3 or any later version
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*
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*/
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namespace Friendica\Util;
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use Friendica\Core\Cache\Duration;
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use Friendica\Core\Logger;
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use Exception;
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use Friendica\DI;
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/**
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* This class contain methods to work with JsonLD data
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*/
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class JsonLD
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{
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/**
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* Loader for LD-JSON validation
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*
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* @param $url
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*
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* @return mixed the loaded data
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* @throws \JsonLdException
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*/
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public static function documentLoader($url)
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{
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$recursion = 0;
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$x = debug_backtrace();
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if ($x) {
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foreach ($x as $n) {
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if ($n['function'] === __FUNCTION__) {
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$recursion ++;
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}
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}
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}
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if ($recursion > 5) {
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Logger::error('jsonld bomb detected at: ' . $url);
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exit();
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}
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$result = DI::cache()->get('documentLoader:' . $url);
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if (!is_null($result)) {
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return $result;
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}
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$data = jsonld_default_document_loader($url);
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DI::cache()->set('documentLoader:' . $url, $data, Duration::DAY);
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return $data;
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}
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/**
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* Normalises a given JSON array
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*
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* @param array $json
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*
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* @return mixed|bool normalized JSON string
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* @throws Exception
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*/
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public static function normalize($json)
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{
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jsonld_set_document_loader('Friendica\Util\JsonLD::documentLoader');
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$jsonobj = json_decode(json_encode($json, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
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try {
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$normalized = jsonld_normalize($jsonobj, array('algorithm' => 'URDNA2015', 'format' => 'application/nquads'));
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}
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catch (Exception $e) {
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$normalized = false;
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$messages = [];
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$currentException = $e;
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do {
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$messages[] = $currentException->getMessage();
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} while($currentException = $currentException->getPrevious());
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Logger::warning('JsonLD normalize error');
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Logger::notice('JsonLD normalize error', ['messages' => $messages]);
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Logger::info('JsonLD normalize error', ['trace' => $e->getTraceAsString()]);
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Logger::debug('JsonLD normalize error', ['jsonobj' => $jsonobj]);
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}
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return $normalized;
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}
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/**
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* Compacts a given JSON array
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*
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* @param array $json
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*
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* @return array Compacted JSON array
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* @throws Exception
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*/
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public static function compact($json)
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{
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jsonld_set_document_loader('Friendica\Util\JsonLD::documentLoader');
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$context = (object)['as' => 'https://www.w3.org/ns/activitystreams#',
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'w3id' => 'https://w3id.org/security#',
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'ldp' => (object)['@id' => 'http://www.w3.org/ns/ldp#', '@type' => '@id'],
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'vcard' => (object)['@id' => 'http://www.w3.org/2006/vcard/ns#', '@type' => '@id'],
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'dfrn' => (object)['@id' => 'http://purl.org/macgirvin/dfrn/1.0/', '@type' => '@id'],
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'diaspora' => (object)['@id' => 'https://diasporafoundation.org/ns/', '@type' => '@id'],
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'ostatus' => (object)['@id' => 'http://ostatus.org#', '@type' => '@id'],
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'dc' => (object)['@id' => 'http://purl.org/dc/terms/', '@type' => '@id'],
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'toot' => (object)['@id' => 'http://joinmastodon.org/ns#', '@type' => '@id'],
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'litepub' => (object)['@id' => 'http://litepub.social/ns#', '@type' => '@id'],
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'sc' => (object)['@id' => 'http://schema.org#', '@type' => '@id'],
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'pt' => (object)['@id' => 'https://joinpeertube.org/ns#', '@type' => '@id']];
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// Preparation for adding possibly missing content to the context
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if (!empty($json['@context']) && is_string($json['@context'])) {
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$json['@context'] = [$json['@context']];
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}
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// Workaround for servers with missing context
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// See issue https://github.com/nextcloud/social/issues/330
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if (!empty($json['@context']) && is_array($json['@context'])) {
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$json['@context'][] = 'https://w3id.org/security/v1';
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}
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// Trying to avoid memory problems with large content fields
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if (!empty($json['object']['source']['content'])) {
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$content = $json['object']['source']['content'];
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$json['object']['source']['content'] = '';
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}
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$jsonobj = json_decode(json_encode($json, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
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try {
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$compacted = jsonld_compact($jsonobj, $context);
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}
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catch (Exception $e) {
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$compacted = false;
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Logger::error('compacting error');
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// Sooner or later we should log some details as well - but currently this leads to memory issues
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// Logger::log('compacting error:' . substr(print_r($e, true), 0, 10000), Logger::DEBUG);
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}
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$json = json_decode(json_encode($compacted, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE), true);
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if (isset($json['as:object']['as:source']['as:content']) && !empty($content)) {
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$json['as:object']['as:source']['as:content'] = $content;
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}
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return $json;
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}
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/**
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* Fetches an element array from a JSON array
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*
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* @param $array
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* @param $element
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* @param $key
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*
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* @return array fetched element
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*/
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public static function fetchElementArray($array, $element, $key = '@id')
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{
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if (empty($array)) {
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return null;
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}
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if (!isset($array[$element])) {
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return null;
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}
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// If it isn't an array yet, make it to one
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if (!is_int(key($array[$element]))) {
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$array[$element] = [$array[$element]];
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}
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$elements = [];
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foreach ($array[$element] as $entry) {
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if (!is_array($entry)) {
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$elements[] = $entry;
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} elseif (isset($entry[$key])) {
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$elements[] = $entry[$key];
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} elseif (!empty($entry) || !is_array($entry)) {
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$elements[] = $entry;
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}
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}
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return $elements;
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}
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/**
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* Fetches an element from a JSON array
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*
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* @param $array
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* @param $element
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* @param $key
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* @param $type
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* @param $type_value
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*
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* @return string fetched element
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*/
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public static function fetchElement($array, $element, $key = '@id', $type = null, $type_value = null)
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{
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if (empty($array)) {
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return null;
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}
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if (!isset($array[$element])) {
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return null;
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}
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if (!is_array($array[$element])) {
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return $array[$element];
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}
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if (is_null($type) || is_null($type_value)) {
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$element_array = self::fetchElementArray($array, $element, $key);
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if (is_null($element_array)) {
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return null;
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}
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return array_shift($element_array);
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}
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$element_array = self::fetchElementArray($array, $element);
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if (is_null($element_array)) {
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return null;
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}
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foreach ($element_array as $entry) {
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if (isset($entry[$key]) && isset($entry[$type]) && ($entry[$type] == $type_value)) {
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return $entry[$key];
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}
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}
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return null;
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}
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}
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