How to read user unique code from _ga cookie?

Question

Currently I am facing the problem that have been discussed already here: How to keep track of a unique and an existing visitor (keep track about unique user without registration etc.). The most suitable answer was: "Try _ga cookie". So my questestion is how can I do that on my PHP website?

I want something like this:

1. User came to my website and performs some action
2. I "look into his _ga cookie" and take some "identification code"
3. I log about this action to the database
4. When user will come again and he will want to perform action again, then I look into my log and I will realize that this is same user

My question is:

How to read user identification from _ga ?

Answer 1

Just get _ga cookie - it is a string with dot separated values. You are looking for third value...

  public static function getGaCode() {

    // Check fo cookie
    $name = "_ga";
    if (!isset($_COOKIE[$name])) {
      return null;
    }

    // Parse cookie _ga='<something>.<something>.<clientid>.<timestamp>';
    return explode(".", $_COOKIE[$name])[2];
  }