javascript variable parsing by php regex - php

Question

I am trying to parse some javascript variables using PHP.
Random website: (not my website)
//.... content ...
function(response) {
if (response) {
var data = { id: "fka1q021", action: "post", date: "today" };
}
//.....
$url = 'www.website.com';
$content = htmlspecialchars(file_get_contents($url));
preg_match_all('/var data = { id: "(.*?)", action: "post", date: "today" };/', $content, $matches);
print_r($matches);
Output:
Array ( [0] => Array ( ) [1] => Array ( ) )
I want to get value of id which is fka1q021
How can I get it? Thanks

Answer 1

You may want to try preg_match instead of preg_match_all. Then, the $matches array will contain the entire matched expression as its 0th element, and the match within your parenthesized sub-expression as its 1st element. That 1st element is the id you're looking for.
So, try:
preg_match('/var data = { id: "(.*?)", action: "post", date: "today" };/', $content, $matches);
Here is full example code:
<?php
$content = <<<ENDOFCONTENT
//.... content ...
function(response) {
if (response) {
var data = { id: "fka1q021", action: "post", date: "today" };
}
//.....
ENDOFCONTENT;
preg_match('/var data = { id: "(.*?)", action: "post", date: "today" };/', $content, $matches);
print_r($matches);
print "id = " . $matches[1] . "\n";
Here is resulting output:
Array
(
[0] => var data = { id: "fka1q021", action: "post", date: "today" };
[1] => fka1q021
)
id = fka1q021

Answer 2

You are not getting anything with your regular expression, because you are applying htmlspecialchars to the content you are reading – and that replaces " with ", so your expression does not find the " you have in there.
Just remove htmlspecialchars, and your pattern will match.

Answer 3

Javascript is client side and PHP is server side, so all the PHP will have executed before the Javascript can run. See this question: How to pass JavaScript variables to PHP?

Answer 4

I'm not sure what your doing is legit... JS ans PHP doesn't execute at the same time and in the same place. Maybe you got this after an ajax call ?
Anyway, analysing a JS data with php can be done with json_decode. I think your problem here will be that json_decode won't understand {id:"value"}, he needs {"id":"value"} instead...
if ( preg_match("#data = ({[^}]*})#",$data,$matches) )
json_decode($matches[1]) ;
For example,
print_r(json_decode('{"id":"fka1q021","action":"post","date":"today"}') );
Render a php object :
stdClass Object
(
[id] => fka1q021
[action] => post
[date] => today
)

Answer 5

A very simple regex is
(?:id:\s(\".*?\"))
Debuggex Demo
then the id will be in capture group 1.
Let me know if you need a more complex regex. And if so, provide more info.