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 ?

• gnud: Please explain why you can't JSONify it. That would simplify everything a whole lot.
• Alsciende: As said, this is not valid JSON. Valid JSON requires objects keys to be formated like strings, ie enclosed with double quotes.
• Alsciende: I was replying to a now-deleted comment. I can't make a valid string because I'm not making the string. Someone else does.
• Alsciende: It's not standard JSON, but it's standard Javascript. Hence the title of my question.
• jpeltoniemi: 8 comments to get to something that was already obvious. Well done :D

Answer 1

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}',

• Alsciende: It's really really nice. Two remarks : Javascript object keys can be enclosed in simple quotes or doubles quotes (usually if the key is not a valid identifier (eg contains a space)). And undefined is a valid value.
• Alsciende: I guess it won't work if an object is included in the value of another object and strrpos isn't right, eg '{fu:{fu:"bar"},bar:{fu:"bar"}}'
• gnud: I think it will now, I've fixed some bugs for dicts in dicts and arrays in arrays. Your test string works now.
• gnud: This version handles quoted keys, and converts undefined to null.
• Dr. DS: @gnud your code breaks on following javascript object {name:"Andrew", age: "11", toys: { car: [{color:"red", wheel: "1"} ,{color:"white", wheel: "4"}]}, bus: [ {av: "Mug 2013", var: [ {color:"red", wheel: "10"} ,{color:"white", wheel: "34"}], totl: 10,buy: true}]}

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

I found out that the Yii-framework's CJSON::decode() function handles Javascript objects as well.

If you're not using Yii, you should be able to just use the source code

• PeterM: For encoding JavaScript objects (and scalar values) check out CJavaScript which does great job with encoding.

Answer 4

thank luttkens

the CJON::decode() class of the Yii-framework works perfectly !

require_once ($_SERVER['DOCUMENT_ROOT']."/phplib/CJSON.php");
$json = new CJSON();
$data = $json->decode('{ url : "/jslib/maps/marker/marker_red.png", height : 34, width : 20, anchorIcon : [5,25.5], anchorText : [0,2], }', true);
print_r( $data );

result :

Array
(
 [url] => /jslib/maps/marker/marker_red.png
 [height] => 34
 [width] => 20
 [anchorIcon] => Array
 (
 [0] => 5
 [1] => 25.5
 )
 [anchorText] => Array
 (
 [0] => 0
 [1] => 2
 )
)

Answer 5

What about that library? http://timwhitlock.info/tag/jparser/

I haven't tried it yet.

Answer 6

PHP does not design for Parsing (Complicate) Javascript String, which contains function, variable, syntax, etc ...
You should use Browser for this task. And we have chrome-php with chrome headless mode.
Install it, and use something like this.

$evaluation = $page->callFunction(
 "function(a, b) {\n window.foo = '{fu:\"bar\",baz:[\"bat\"]}';\n}",
 [1, 2]
);
$value = $evaluation->getReturnValue();