Split magnet link with PHP

Question

I need two items in a magnet link:

magnet:?xt=urn:btih:0eb69459a28b08400c5f05bad3e63235b9853021&dn=Splinter.Cell.Blacklist-RELOADED&tr=udp%3A%2F%2Ftracker.com%3A80&tr=udp%3A%2F%2Ftracker.publicbt.com%3A80&tr=udp%3A%2F%2Ftracker.istole.it%3A6969&tr=udp%3A%2F%2Ftracker.ccc.de%3A80&tr=udp%3A%2F%2Fopen.demonii.com%3A1337

the value of btih:

0eb69459a28b08400c5f05bad3e63235b9853021

and the value of the first udp:

udp://tracker.com:80

How to do this with PHP?

Try [hakre](http://stackoverflow.com/users/367456/hakre)'s [Magnet Link Library for PHP](https://gist.github.com/hakre/1949740). — Dave Chen, Apr 19 '14 at 01:01
Why are these answers even bothering with regex? Don't use a tool just to use it, use it when it is useful. I'm not saying the answers don't work, but they aren't decoding based on the format. Here's my go at it: http://pastebin.com/DXDKVzFV — Chinoto Vokro, Oct 19 '14 at 20:26

score 6 · Answer 1 · answered Apr 19 '14 at 01:23

As parse_url() wont help in this situation your have to use regex to parse the string, and then further manipulate the string to get the trackers. So something like:

<?php 
$string = 'magnet:?xt=urn:btih:0eb69459a28b08400c5f05bad3e63235b9853021&dn=Splinter.Cell.Blacklist-RELOADED&tr=udp%3A%2F%2Ftracker.com%3A80&tr=udp%3A%2F%2Ftracker.publicbt.com%3A80&tr=udp%3A%2F%2Ftracker.istole.it%3A6969&tr=udp%3A%2F%2Ftracker.ccc.de%3A80&tr=udp%3A%2F%2Fopen.demonii.com%3A1337';

preg_match('#magnet:\?xt=urn:btih:(?<hash>.*?)&dn=(?<filename>.*?)&tr=(?<trackers>.*?)$#', $string, $magnet_link);

//0eb69459a28b08400c5f05bad3e63235b9853021
echo $magnet_link['hash'];

//Splinter.Cell.Blacklist-RELOADED
echo $magnet_link['filename'];

/*[trackers] => Array
(
    [0] => udp://tracker.com:80
    [1] => udp://tracker.publicbt.com:80
    [2] => udp://tracker.istole.it:6969
    [3] => udp://tracker.ccc.de:80
    [4] => udp://open.demonii.com:1337
)
*/
$magnet_link['trackers'] = explode('&', urldecode(str_replace('tr=','', $magnet_link['trackers'])));

//so to get first tracker
$magnet_link['trackers'][0];
?>

almost 5 years later and a response saves 3 hours of research, thanks — Vitor Hugo, Dec 20 '18 at 10:43

score 3 · Answer 2 · answered Apr 19 '14 at 01:24

As recommended in the question comments, there appear to be several existing libraries for magnet links - you should probably take a look at these.

If you want to do it yourself however, one way would be to regex for the values. Let's assume that your magnet link is assigned to a variable $link like so:

$link ='magnet:?xt=urn:btih:0eb69459a28b08400c5f05bad3e63235b9853021&dn=Splinter.Cell.Blacklist-RELOADED&tr=udp%3A%2F%2Ftracker.com%3A80&tr=udp%3A%2F%2Ftracker.publicbt.com%3A80&tr=udp%3A%2F%2Ftracker.istole.it%3A6969&tr=udp%3A%2F%2Ftracker.ccc.de%3A80&tr=udp%3A%2F%2Fopen.demonii.com%3A1337';

A quick way to get each value is to run a separate preg_match() for each value - you could combine the two regexes and run preg_match_all() but let's keep it basic. We're going to use lookbehind assertions to try and find the required values.

// your magnet link
$link = 'magnet:?xt=urn:btih:0eb69459a28b08400c5f05bad3e63235b9853021&dn=Splinter.Cell.Blacklist-RELOADED&tr=udp%3A%2F%2Ftracker.com%3A80&tr=udp%3A%2F%2Ftracker.publicbt.com%3A80&tr=udp%3A%2F%2Ftracker.istole.it%3A6969&tr=udp%3A%2F%2Ftracker.ccc.de%3A80&tr=udp%3A%2F%2Fopen.demonii.com%3A1337';

// urls are encoded, let's reverse that
$link = urldecode($link); 

// first regex searches for 'btih:' and matches subsequent 
// word characters ([a-zA-Z0-9_])
// match(es) are captured as an array to $matchBtih
preg_match('/(?<=btih:)\w+/', $link, $matchBtih);

// same again, more or less, capturing word characters, colon and full-stop
// match(es) are captured as an array to $matchUdp
preg_match('/(?<=tr=)udp:\/\/[\w\:\.]+/', $link, $matchUdp);

// show results
var_dump($matchBtih, $matchUdp);

Should yield:

array (size=1)
  0 => string '0eb69459a28b08400c5f05bad3e63235b9853021' (length=40)
array (size=1)
  0 => string 'udp://tracker.com:80' (length=20)

Hope this helps :)

Snap! Ha... indeed! Funny you mention `parse_url()` - I initially assumed it was the way to go, but after some experimentation it would seem not! — Darragh Enright, Apr 19 '14 at 01:26

Split magnet link with PHP

2 Answers2