1 common.inc backdrop_json_decode_unicode($json)

Decode Unicode characters in JSON strings.

This function is no longer used directly in core. Use backdrop_json_encode() to format JSON.


since 1.22.0


core/includes/common.inc, line 5812
Common functions that many Backdrop modules will need to reference.


function backdrop_json_decode_unicode($json) {
  watchdog_deprecated_function('common', __FUNCTION__);
  // Convert escaped characters, such as \u00e9 to the unescaped version (é).
  // See http://stackoverflow.com/questions/2934563/how-to-decode-unicode-escape-sequences-like-u00ed-to-proper-utf-8-encoded-cha
  $decode_callback = function($match) {
    // Leave control characters such as NULL, backspace, etc. encoded.
    if (hexdec($match[2]) < 32) {
      $string = '\u' . $match[2];
    else {
      $string = mb_convert_encoding(pack('H*', $match[2]), 'UTF-8', 'UCS-2BE');
    return $match[1] . $string;
  // To prevent unintentionally unescaping the string "\u", be sure that the
  // the backslash itself is not also escaped. Note that because the replacement
  // may include part of a 4-digit code for a previous Unicode character, this
  // will only escape every-other Unicode character if they are next to each
  // other.
  $pattern = '/([^\\\\])\\\\u([0-9a-fA-F]{4})/';
  $json = preg_replace_callback($pattern, $decode_callback, $json);
  // Replace a second time to catch any sequences multiple Unicode characters.
  return preg_replace_callback($pattern, $decode_callback, $json);