Question

Trying to demystify the Like button as of December 2011.

http://developers.facebook.com/docs/reference/plugins/like/

Have 2 questions:

1. How do I include a “src” and “ref” paramater in the URL that the user is liking? I realize this is well documented, yet I couldn’t actually do it in my testing… please provide an example of this.
2. How can I stuff the UID of user that is liking it onto the link that they are liking for example, if they like http://example.com, I’d like the link to be formed http://example.com?src=fb&ref=1234567

Please point me to any examples, thanks!

Answer 1

I am assuming that you have the user-id.
You can specify the ref parameter as follows, (XFBML version)

<fb:like href="http://example.com/fblikepage.php" 
     send="true" width="450" show_faces="true"
     ref="<?php echo $userid; ?>"
>
</fb:like>

There is no way you can specify the src parameter, it’ll be automatically appended by Facebook, when you specify the ref parameter as shown above. The url will look like this on Facebook : http://www.example.com/fblikepage.php?fb_ref=xyz&fb_source=profile_oneline. See the following part from the documentation.

ref – a label for tracking referrals; must be less than 50 characters and can contain alphanumeric characters and some punctuation (currently +/=-.:_). The ref attribute causes two parameters to be added to the referrer URL when a user clicks a link from a stream story about a Like action:
fb_ref – the ref parameter
fb_source – the stream type (‘home’, ‘profile’, ‘search’, ‘other’) in which the click occurred and the story type (‘oneline’ or ‘multiline’), concatenated with an underscore.

Ofcourse the fb_source parameter will vary according to where the url is shown on Facebook and that will be done by Facebook. If you want to know whether a user is visiting through Facebook or not, you can just see if the fb_source parameter is there in the $_REQUEST variable, something like this:

<?php
 /* lots of code */
 if(isset($_REQUEST['fb_source'])){
   // we know the current user is visiting through some link on Facebook, so you can do whatever you wanted here
 }

Hope this helps.