How can I check if a facebook like button has been clicked?

Question

I've put facebook like buttons into my wordpress blog... the idea is to use them as kind of a voting mechanism for posts. What I would like to do is automatically add a comment for the blog post everytime someone 'likes' it via the facebook like button.

So my question is- does the like button api provide some kind of a callback to my page if someone 'successfully' likes something? - ie. they have not already liked it before, and they get through the process of submitting it to facebook successfully.

Thanks for any help. Fyi I am very new to the facebook api

-rich

Solution 1

You need to subscribe to edge.create event according to docs:

FB.Event.subscribe('edge.create', function(href, widget) {
   alert('You just liked '+href);
});

but for some reason I couldn't make it work last time I tried...

Solution 2

You can check it using the folowing facebook-api call:

JavaScript (untested):

FB.api({ method: 'pages.isFan', page_id: 'YOUR-PAGE-ID' }, function(resp) {
    if (resp) {
      alert('You like the Application.');
    } else {
      alert('You don't like the Application.');
    }
 });

PHP (well tested):

$facebook = new Facebook(array(
    'appId' => 'YOUR-APP-ID',
    'secret' => 'YOUR-APP-SECRET-KEY',
));
$facebook->api(array(
                'method' => 'pages.isFan',
                'page_id' => 'YOUR-PAGE-KEY'
            ))

Source: http://forum.developers.facebook.net/viewtopic.php?id=101406

For further informations see the Facebook Developer Manual. http://developers.facebook.com/docs/reference/rest/pages.isFan/

Please remember that the REST-API (used in this examples) will be deprecated soon.

If you don't know where to get the SDKs you can take a look at this page: http://developers.facebook.com/docs/sdks/

Solution 3

I use this to get track of the liked of users. In this case every time one user press the like button it mades a post (its send some hidden id )to another php file and save it to my database. i use this for something like you whant to do.

NOTE: i use jquery to build the ajax post.

-------------------------------------------
  window.fbAsyncInit = function() {

    FB.init({appId: 'xxxxxxxxxxxxxxxxxx', status: true, cookie: true,
             xfbml: true});

B.Event.subscribe('edge.create', function(href, widget) {

$(document).ready(function() { 

var h_fbl=href.split("/");

var fbl_id=h_fbl[4]; 


 $.post("http://mypage.com/like.php",{ idfb:fbl_id,rand:Math.random() } )

}) });
  };