$re = '/^event\s*\[(\d+),"([^"]+)",(\{.*\})\]$/mi';
$str = 'Handshake [0,"957529506107a4c7b3dba869424463",1,"Ratchet/0.3.6"]
Event [8,"316662",{"id":1115411,"side":"left"}]';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php