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   1  <?php
   2  /**
   3   * Metadata API
   4   *
   5   * Functions for retrieving and manipulating metadata of various WordPress object types.  Metadata
   6   * for an object is a represented by a simple key-value pair.  Objects may contain multiple
   7   * metadata entries that share the same key and differ only in their value.
   8   *
   9   * @package WordPress
  10   * @subpackage Meta
  11   * @since 2.9.0
  12   */
  13  
  14  /**
  15   * Add metadata for the specified object.
  16   *
  17   * @since 2.9.0
  18   * @uses $wpdb WordPress database object for queries.
  19   * @uses do_action() Calls 'added_{$meta_type}_meta' with meta_id of added metadata entry,
  20   *         object ID, meta key, and meta value
  21   *
  22   * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
  23   * @param int $object_id ID of the object metadata is for
  24   * @param string $meta_key Metadata key
  25   * @param string $meta_value Metadata value
  26   * @param bool $unique Optional, default is false.  Whether the specified metadata key should be
  27   *         unique for the object.  If true, and the object already has a value for the specified
  28   *         metadata key, no change will be made
  29   * @return bool True on successful update, false on failure.
  30   */
  31  function add_metadata($meta_type, $object_id, $meta_key, $meta_value, $unique = false) {
  32      if ( !$meta_type || !$meta_key )
  33          return false;
  34  
  35      if ( !$object_id = absint($object_id) )
  36          return false;
  37  
  38      if ( ! $table = _get_meta_table($meta_type) )
  39          return false;
  40  
  41      global $wpdb;
  42  
  43      $column = esc_sql($meta_type . '_id');
  44  
  45      // expected_slashed ($meta_key)
  46      $meta_key = stripslashes($meta_key);
  47  
  48      if ( $unique && $wpdb->get_var( $wpdb->prepare(
  49          "SELECT COUNT(*) FROM $table WHERE meta_key = %s AND $column = %d",
  50          $meta_key, $object_id ) ) )
  51          return false;
  52  
  53      $_meta_value = $meta_value;
  54      $meta_value = maybe_serialize( stripslashes_deep($meta_value) );
  55  
  56      $wpdb->insert( $table, array(
  57          $column => $object_id,
  58          'meta_key' => $meta_key,
  59          'meta_value' => $meta_value
  60      ) );
  61  
  62      wp_cache_delete($object_id, $meta_type . '_meta');
  63      // users cache stores usermeta that must be cleared.
  64      if ( 'user' == $meta_type )
  65          clean_user_cache($object_id);
  66  
  67      do_action( "added_{$meta_type}_meta", $wpdb->insert_id, $object_id, $meta_key, $_meta_value );
  68  
  69      return true;
  70  }
  71  
  72  /**
  73   * Update metadata for the specified object.  If no value already exists for the specified object
  74   * ID and metadata key, the metadata will be added.
  75   *
  76   * @since 2.9.0
  77   * @uses $wpdb WordPress database object for queries.
  78   * @uses do_action() Calls 'update_{$meta_type}_meta' before updating metadata with meta_id of
  79   *         metadata entry to update, object ID, meta key, and meta value
  80   * @uses do_action() Calls 'updated_{$meta_type}_meta' after updating metadata with meta_id of
  81   *         updated metadata entry, object ID, meta key, and meta value
  82   *
  83   * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
  84   * @param int $object_id ID of the object metadata is for
  85   * @param string $meta_key Metadata key
  86   * @param string $meta_value Metadata value
  87   * @param string $prev_value Optional.  If specified, only update existing metadata entries with
  88   *         the specified value.  Otherwise, update all entries.
  89   * @return bool True on successful update, false on failure.
  90   */
  91  function update_metadata($meta_type, $object_id, $meta_key, $meta_value, $prev_value = '') {
  92      if ( !$meta_type || !$meta_key )
  93          return false;
  94  
  95      if ( !$object_id = absint($object_id) )
  96          return false;
  97  
  98      if ( ! $table = _get_meta_table($meta_type) )
  99          return false;
 100  
 101      global $wpdb;
 102  
 103      $column = esc_sql($meta_type . '_id');
 104      $id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
 105  
 106      // expected_slashed ($meta_key)
 107      $meta_key = stripslashes($meta_key);
 108  
 109      if ( ! $meta_id = $wpdb->get_var( $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s AND $column = %d", $meta_key, $object_id ) ) )
 110          return add_metadata($meta_type, $object_id, $meta_key, $meta_value);
 111  
 112      // Compare existing value to new value if no prev value given and the key exists only once.
 113      if ( empty($prev_value) ) {
 114          $old_value = get_metadata($meta_type, $object_id, $meta_key);
 115          if ( count($old_value) == 1 ) {
 116              if ( $old_value[0] === $meta_value )
 117                  return false;
 118          }
 119      }
 120  
 121      $_meta_value = $meta_value;
 122      $meta_value = maybe_serialize( stripslashes_deep($meta_value) );
 123  
 124      $data  = compact( 'meta_value' );
 125      $where = array( $column => $object_id, 'meta_key' => $meta_key );
 126  
 127      if ( !empty( $prev_value ) ) {
 128          $prev_value = maybe_serialize($prev_value);
 129          $where['meta_value'] = $prev_value;
 130      }
 131  
 132      do_action( "update_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );
 133  
 134      $wpdb->update( $table, $data, $where );
 135      wp_cache_delete($object_id, $meta_type . '_meta');
 136      // users cache stores usermeta that must be cleared.
 137      if ( 'user' == $meta_type )
 138          clean_user_cache($object_id);
 139  
 140      do_action( "updated_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );
 141  
 142      return true;
 143  }
 144  
 145  /**
 146   * Delete metadata for the specified object.
 147   *
 148   * @since 2.9.0
 149   * @uses $wpdb WordPress database object for queries.
 150   * @uses do_action() Calls 'deleted_{$meta_type}_meta' after deleting with meta_id of
 151   *         deleted metadata entries, object ID, meta key, and meta value
 152   *
 153   * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
 154   * @param int $object_id ID of the object metadata is for
 155   * @param string $meta_key Metadata key
 156   * @param string $meta_value Optional. Metadata value.  If specified, only delete metadata entries
 157   *         with this value.  Otherwise, delete all entries with the specified meta_key.
 158   * @param bool $delete_all Optional, default is false.  If true, delete matching metadata entries
 159   *         for all objects, ignoring the specified object_id.  Otherwise, only delete matching
 160   *         metadata entries for the specified object_id.
 161   * @return bool True on successful delete, false on failure.
 162   */
 163  function delete_metadata($meta_type, $object_id, $meta_key, $meta_value = '', $delete_all = false) {
 164      if ( !$meta_type || !$meta_key )
 165          return false;
 166  
 167      if ( (!$object_id = absint($object_id)) && !$delete_all )
 168          return false;
 169  
 170      if ( ! $table = _get_meta_table($meta_type) )
 171          return false;
 172  
 173      global $wpdb;
 174  
 175      $type_column = esc_sql($meta_type . '_id');
 176      $id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
 177      // expected_slashed ($meta_key)
 178      $meta_key = stripslashes($meta_key);
 179      $meta_value = maybe_serialize( stripslashes_deep($meta_value) );
 180  
 181      $query = $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s", $meta_key );
 182  
 183      if ( !$delete_all )
 184          $query .= $wpdb->prepare(" AND $type_column = %d", $object_id );
 185  
 186      if ( $meta_value )
 187          $query .= $wpdb->prepare(" AND meta_value = %s", $meta_value );
 188  
 189      $meta_ids = $wpdb->get_col( $query );
 190      if ( !count( $meta_ids ) )
 191          return false;
 192  
 193      $query = "DELETE FROM $table WHERE $id_column IN( " . implode( ',', $meta_ids ) . " )";
 194  
 195      $count = $wpdb->query($query);
 196  
 197      if ( !$count )
 198          return false;
 199  
 200      wp_cache_delete($object_id, $meta_type . '_meta');
 201      // users cache stores usermeta that must be cleared.
 202      if ( 'user' == $meta_type )
 203          clean_user_cache($object_id);
 204  
 205      do_action( "deleted_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $meta_value );
 206  
 207      return true;
 208  }
 209  
 210  /**
 211   * Retrieve metadata for the specified object.
 212   *
 213   * @since 2.9.0
 214   *
 215   * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
 216   * @param int $object_id ID of the object metadata is for
 217   * @param string $meta_key Optional.  Metadata key.  If not specified, retrieve all metadata for
 218   *         the specified object.
 219   * @param bool $single Optional, default is false.  If true, return only the first value of the
 220   *         specified meta_key.  This parameter has no effect if meta_key is not specified.
 221   * @return string|array Single metadata value, or array of values
 222   */
 223  function get_metadata($meta_type, $object_id, $meta_key = '', $single = false) {
 224      if ( !$meta_type )
 225          return false;
 226  
 227      if ( !$object_id = absint($object_id) )
 228          return false;
 229  
 230      $meta_cache = wp_cache_get($object_id, $meta_type . '_meta');
 231  
 232      if ( !$meta_cache ) {
 233          update_meta_cache($meta_type, $object_id);
 234          $meta_cache = wp_cache_get($object_id, $meta_type . '_meta');
 235      }
 236  
 237      if ( ! $meta_key )
 238          return $meta_cache;
 239  
 240      if ( isset($meta_cache[$meta_key]) ) {
 241          if ( $single )
 242              return maybe_unserialize( $meta_cache[$meta_key][0] );
 243          else
 244              return array_map('maybe_unserialize', $meta_cache[$meta_key]);
 245      }
 246  
 247      if ($single)
 248          return '';
 249      else
 250          return array();
 251  }
 252  
 253  /**
 254   * Update the metadata cache for the specified objects.
 255   *
 256   * @since 2.9.0
 257   * @uses $wpdb WordPress database object for queries.
 258   *
 259   * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
 260   * @param int|array $object_ids array or comma delimited list of object IDs to update cache for
 261   * @return mixed Metadata cache for the specified objects, or false on failure.
 262   */
 263  function update_meta_cache($meta_type, $object_ids) {
 264      if ( empty( $meta_type ) || empty( $object_ids ) )
 265          return false;
 266  
 267      if ( ! $table = _get_meta_table($meta_type) )
 268          return false;
 269  
 270      $column = esc_sql($meta_type . '_id');
 271  
 272      global $wpdb;
 273  
 274      if ( !is_array($object_ids) ) {
 275          $object_ids = preg_replace('|[^0-9,]|', '', $object_ids);
 276          $object_ids = explode(',', $object_ids);
 277      }
 278  
 279      $object_ids = array_map('intval', $object_ids);
 280  
 281      $cache_key = $meta_type . '_meta';
 282      $ids = array();
 283      foreach ( $object_ids as $id ) {
 284          if ( false === wp_cache_get($id, $cache_key) )
 285              $ids[] = $id;
 286      }
 287  
 288      if ( empty( $ids ) )
 289          return false;
 290  
 291      // Get meta info
 292      $id_list = join(',', $ids);
 293      $cache = array();
 294      $meta_list = $wpdb->get_results( $wpdb->prepare("SELECT $column, meta_key, meta_value FROM $table WHERE $column IN ($id_list)",
 295          $meta_type), ARRAY_A );
 296  
 297      if ( !empty($meta_list) ) {
 298          foreach ( $meta_list as $metarow) {
 299              $mpid = intval($metarow[$column]);
 300              $mkey = $metarow['meta_key'];
 301              $mval = $metarow['meta_value'];
 302  
 303              // Force subkeys to be array type:
 304              if ( !isset($cache[$mpid]) || !is_array($cache[$mpid]) )
 305                  $cache[$mpid] = array();
 306              if ( !isset($cache[$mpid][$mkey]) || !is_array($cache[$mpid][$mkey]) )
 307                  $cache[$mpid][$mkey] = array();
 308  
 309              // Add a value to the current pid/key:
 310              $cache[$mpid][$mkey][] = $mval;
 311          }
 312      }
 313  
 314      foreach ( $ids as $id ) {
 315          if ( ! isset($cache[$id]) )
 316              $cache[$id] = array();
 317      }
 318  
 319      foreach ( array_keys($cache) as $object)
 320          wp_cache_set($object, $cache[$object], $cache_key);
 321  
 322      return $cache;
 323  }
 324  
 325  /**
 326   * Retrieve the name of the metadata table for the specified object type.
 327   *
 328   * @since 2.9.0
 329   * @uses $wpdb WordPress database object for queries.
 330   *
 331   * @param string $meta_type Type of object to get metadata table for (e.g., comment, post, or user)
 332   * @return mixed Metadata table name, or false if no metadata table exists
 333   */
 334  function _get_meta_table($type) {
 335      global $wpdb;
 336  
 337      $table_name = $type . 'meta';
 338  
 339      if ( empty($wpdb->$table_name) )
 340          return false;
 341  
 342      return $wpdb->$table_name;
 343  }
 344  ?>