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Getting cookie information

Domain user information​

You can use the following function to extract the Domain User Information from the ID cookie:

/*
* Function to extract the Snowplow Domain User Information from the first-party cookie set by the Snowplow JavaScript Tracker
*
* @param string cookieName (optional) The value used for "cookieName" in the tracker constructor argmap
* (leave blank if you did not set a custom cookie name)
*
* @return string or bool The ID string if the cookie exists or false if the cookie has not been set yet
*/
function getSnowplowDuid(cookieName) {
  var cookieName = cookieName || '_sp_';
  var matcher = new RegExp(cookieName + 'id\\.[a-f0-9]+=([^;]+);?');
  var match = document.cookie.match(matcher);
  var split = match[1].split('.');
  if (match && match[1]) {
    return {
      'domain_userid': split[0],
      'domain_sessionidx': split[2],
      'domain_sessionid': split[5]
    }
  } else {
    return false;
  }
}

If you set a custom cookieName field in the argmap, pass that name into the function; otherwise call the function without arguments. Note that if the function is called before the cookie exists (i.e. when the user is visiting the page for the first time and sp.js has not yet loaded) if will return false.

It's possible to retrieve cookie properties for use in your code (as well as the page view UUID and user ID) using a tracker callback. This is an advanced usage of the tracker.

If you call snowplow with a function as the argument, the function will be executed when sp.js loads:

snowplow(function () {
  console.log("sp.js has loaded");
});

Or equivalently:

snowplow(function (x) {
  console.log(x);
}, "sp.js has loaded");

The callback you provide is executed as a method on the internal trackerDictionary object. This means that you can access the trackerDictionary using this.

// Configure a tracker instance named "sp"
snowplow('newTracker', 'sp', '{{COLLECTOR_URL}', {
 appId: 'snowplowExampleApp'
});

// Access the tracker instance inside a callback
snowplow(function () {
 var sp = this.sp;
 var domainUserId = sp.getDomainUserId();
 console.log(domainUserId);
})

The callback function should not be a method:

// TypeError: Illegal invocation
snowplow(console.log, "sp.js has loaded");

This will not work because the value of this in the console.log function will be the trackerDictionary rather than console.

You can get around this problem using Function.prototoype.bind as follows:

snowplow(console.log.bind(console), "sp.js has loaded");

For more on execution context in JavaScript, see the MDN page.

getDomainUserId​

The getDomainUserId method returns the user ID stored in the first-party cookie:

// Access the tracker instance inside a callback
snowplow(function () {
 var sp = this.sp;
 var domainUserId = sp.getDomainUserId();
 console.log(domainUserId);
})

getDomainUserInfo​

The getDomainUserInfo method returns all the information stored in first-party cookie in an array:

// Access the tracker instance inside a callback
snowplow(function () {
 var sp = this.sp;
 var domainUserInfo = sp.getDomainUserInfo();
 console.log(domainUserInfo);
})

The domainUserInfo variable will contain an array with 11 elements:

  1. A string set to '1' if this is the user's first session and '0' otherwise
  2. The domain user ID
  3. The timestamp at which the cookie was created
  4. The number of times the user has visited the site
  5. The timestamp for the current visit
  6. The timestamp of the last visit
  7. The session id
  8. ID of the previous session (since version 3.5)
  9. ID of the first event in the current session (since version 3.5)
  10. Device created timestamp of the first event in the current session (since version 3.5)
  11. Index of the last event in the session (used to inspect order of events) (since version 3.5)

getCookieName​

The getCookieName method returns the complete cookie name for the domain or session cookie:

// Access the tracker instance inside a callback
snowplow(function () {
 var sp = this.sp;
 var cookieName = sp.getCookieName('id');
 console.log(cookieName);
})

The argument corresponds to the basename of the cookie: 'id' for the domain cookie, 'ses' for the session cookie.