src/Util/JsonLD.php

   1 <?php
   2 /**
   3  * @file src/Util/JsonLD.php
   4  */
   5 namespace Friendica\Util;
   6
   7 use Friendica\Core\Cache;
   8 use Exception;
   9
  10 /**
  11  * @brief This class contain methods to work with JsonLD data
  12  */
  13 class JsonLD
  14 {
  15         /**
  16          * @brief Loader for LD-JSON validation
  17          *
  18          * @param $url
  19          *
  20          * @return the loaded data
  21          */
  22         public static function documentLoader($url)
  23         {
  24                 $recursion = 0;
  25
  26                 $x = debug_backtrace();
  27                 if ($x) {
  28                         foreach ($x as $n) {
  29                                 if ($n['function'] === __FUNCTION__)  {
  30                                         $recursion ++;
  31                                 }
  32                         }
  33                 }
  34
  35                 if ($recursion > 5) {
  36                         logger('jsonld bomb detected at: ' . $url);
  37                         exit();
  38                 }
  39
  40                 $result = Cache::get('documentLoader:' . $url);
  41                 if (!is_null($result)) {
  42                         return $result;
  43                 }
  44
  45                 $data = jsonld_default_document_loader($url);
  46                 Cache::set('documentLoader:' . $url, $data, CACHE_DAY);
  47                 return $data;
  48         }
  49
  50         /**
  51          * @brief Normalises a given JSON array
  52          *
  53          * @param array $json
  54          *
  55          * @return normalized JSON string
  56          */
  57         public static function normalize($json)
  58         {
  59                 jsonld_set_document_loader('Friendica\Util\JsonLD::documentLoader');
  60
  61                 $jsonobj = json_decode(json_encode($json, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
  62
  63                 try {
  64                         $normalized = jsonld_normalize($jsonobj, array('algorithm' => 'URDNA2015', 'format' => 'application/nquads'));
  65                 }
  66                 catch (Exception $e) {
  67                         $normalized = false;
  68                         logger('normalise error:' . print_r($e, true), LOGGER_DEBUG);
  69                 }
  70
  71                 return $normalized;
  72         }
  73
  74         /**
  75          * @brief Compacts a given JSON array
  76          *
  77          * @param array $json
  78          *
  79          * @return comacted JSON array
  80          */
  81         public static function compact($json)
  82         {
  83                 jsonld_set_document_loader('Friendica\Util\JsonLD::documentLoader');
  84
  85                 $context = (object)['as' => 'https://www.w3.org/ns/activitystreams',
  86                         'w3sec' => 'https://w3id.org/security',
  87                         'ostatus' => (object)['@id' => 'http://ostatus.org#', '@type' => '@id'],
  88                         'vcard' => (object)['@id' => 'http://www.w3.org/2006/vcard/ns#', '@type' => '@id'],
  89                         'uuid' => (object)['@id' => 'http://schema.org/identifier', '@type' => '@id']];
  90
  91                 $jsonobj = json_decode(json_encode($json, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
  92
  93                 $compacted = jsonld_compact($jsonobj, $context);
  94
  95                 return json_decode(json_encode($compacted, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE), true);
  96         }
  97
  98         /**
  99          * @brief Fetches an element from a JSON array
 100          *
 101          * @param $array
 102          * @param $element
 103          * @param $key
 104          * @param $type
 105          * @param $type_value
 106          *
 107          * @return fetched element
 108          */
 109         public static function fetchElement($array, $element, $key, $type = null, $type_value = null)
 110         {
 111                 if (empty($array)) {
 112                         return false;
 113                 }
 114
 115                 if (empty($array[$element])) {
 116                         return false;
 117                 }
 118
 119                 if (is_string($array[$element])) {
 120                         return $array[$element];
 121                 }
 122
 123                 if (is_null($type_value)) {
 124                         if (!empty($array[$element][$key])) {
 125                                 return $array[$element][$key];
 126                         }
 127
 128                         if (!empty($array[$element][0][$key])) {
 129                                 return $array[$element][0][$key];
 130                         }
 131
 132                         return false;
 133                 }
 134
 135                 if (!empty($array[$element][$key]) && !empty($array[$element][$type]) && ($array[$element][$type] == $type_value)) {
 136                         return $array[$element][$key];
 137                 }
 138
 139                 /// @todo Add array search
 140
 141                 return false;
 142         }
 143 }