Parsing Javascript (not JSON) in PHP

Question

I have a php string containing the serialization of a javascript object :

$string = '{fu:"bar",baz:["bat"]}';

The actual string is far more complicated, of course, but still well-formed javascript. This is not standard JSON, so json_decode fails. Do you know any php library that would parse this string and return a php associative array ?

Answer 1

Use JS code by Morten Amundsen, here or here.

It gives you a JS lib to serialize your JS data the same way PHP can unserialize

Answer 2

Pear Services_JSON will parse that string (tested version 1.31). But given that that is a JSON parser and that this isn't valid JSON you have no guarantee that future versions will still work.

Answer 3

This sounded like a fun challenge, so I coded up a tiny parser :D

class JsParserException extends Exception {}
function parse_jsobj($str, &$data) {
    $str = trim($str);
    if(strlen($str) < 1) return;

    if($str{0} != '{') {
     throw new JsParserException('The given string is not a JS object');
    }
    $str = substr($str, 1);

    /* While we have data, and it's not the end of this dict (the comma is needed for nested dicts) */
    while(strlen($str) && $str{0} != '}' && $str{0} != ',') { 
     /* find the key */
     if($str{0} == "'" || $str{0} == '"') {
      /* quoted key */
      list($str, $key) = parse_jsdata($str, ':');
     } else {
      $match = null;
      /* unquoted key */
      if(!preg_match('/^\s*[a-zA-z_][a-zA-Z_\d]*\s*:/', $str, $match)) {
      throw new JsParserException('Invalid key ("'.$str.'")');
      } 
      $key = $match[0];
      $str = substr($str, strlen($key));
      $key = trim(substr($key, 0, -1)); /* discard the ':' */
     }

     list($str, $data[$key]) = parse_jsdata($str, '}');
    }
    "Finshed dict. Str: '$str'\n";
    return substr($str, 1);
}

function comma_or_term_pos($str, $term) {
    $cpos = strpos($str, ',');
    $tpos = strpos($str, $term);
    if($cpos === false && $tpos === false) {
     throw new JsParserException('unterminated dict or array');
    } else if($cpos === false) {
     return $tpos;
    } else if($tpos === false) {
     return $cpos;
    }
    return min($tpos, $cpos);
}

function parse_jsdata($str, $term="}") {
    $str = trim($str);


    if(is_numeric($str{0}."0")) {
     /* a number (int or float) */
     $newpos = comma_or_term_pos($str, $term);
     $num = trim(substr($str, 0, $newpos));
     $str = substr($str, $newpos+1); /* discard num and comma */
     if(!is_numeric($num)) {
      throw new JsParserException('OOPSIE while parsing number: "'.$num.'"');
     }
     return array(trim($str), $num+0);
    } else if($str{0} == '"' || $str{0} == "'") {
     /* string */
     $q = $str{0};
     $offset = 1;
     do {
      $pos = strpos($str, $q, $offset);
      $offset = $pos;
     } while($str{$pos-1} == '\\'); /* find un-escaped quote */
     $data = substr($str, 1, $pos-1);
     $str = substr($str, $pos);
     $pos = comma_or_term_pos($str, $term);
     $str = substr($str, $pos+1);  
     return array(trim($str), $data);
    } else if($str{0} == '{') {
     /* dict */
     $data = array();
     $str = parse_jsobj($str, $data);
     return array($str, $data);
    } else if($str{0} == '[') {
     /* array */
     $arr = array();
     $str = substr($str, 1);
     while(strlen($str) && $str{0} != $term && $str{0} != ',') {
      $val = null;
      list($str, $val) = parse_jsdata($str, ']');
      $arr[] = $val;
      $str = trim($str);
     }
     $str = trim(substr($str, 1));
     return array($str, $arr);
    } else if(stripos($str, 'true') === 0) {
     /* true */
     $pos = comma_or_term_pos($str, $term);
     $str = substr($str, $pos+1); /* discard terminator */
     return array(trim($str), true);
    } else if(stripos($str, 'false') === 0) {
     /* false */
     $pos = comma_or_term_pos($str, $term);
     $str = substr($str, $pos+1); /* discard terminator */
     return array(trim($str), false);
    } else if(stripos($str, 'null') === 0) {
     /* null */
     $pos = comma_or_term_pos($str, $term);
     $str = substr($str, $pos+1); /* discard terminator */
     return array(trim($str), null);
    } else if(strpos($str, 'undefined') === 0) {
     /* null */
     $pos = comma_or_term_pos($str, $term);
     $str = substr($str, $pos+1); /* discard terminator */
     return array(trim($str), null);
    } else {
     throw new JsParserException('Cannot figure out how to parse "'.$str.'" (term is '.$term.')');
    }
}

Usage:

$data = '{fu:"bar",baz:["bat"]}';    
$parsed = array();    
parse_jsobj($data, $parsed);    
var_export($parsed);

Gives:

array (
  'fu' => 'bar',
  'baz' =>
  array (
    0 => 'bat',
  ),
)

Tested with these strings:

'{fu:"bar",baz:["bat"]}',
'{rec:{rec:{rec:false}}}',
'{foo:[1,2,[3,4]]}',
'{fu:{fu:"bar"},bar:{fu:"bar"}}',
'{"quoted key":[1,2,3]}',
'{und:undefined,"baz":[1,2,"3"]}',
'{arr:["a","b"],"baz":"foo","gar":{"faz":false,t:"2"},f:false}',