Maybe I\'ve been sat here too long staring at this but WHY would file_get_contents return false here? I\'ve cut and paste the URL and it works fine
Try this:
$query = http_build_query(array('search'=>$as_any, 'location'=>$location));
$url = "http://jobs.github.com/positions.json?" . $query;
The problem is that you weren't URL-encoding the search term, which contains a space. The request was returning a 400 error from the server, which you'd have noticed if you had error reporting enabled.