In facebook connect, how can I check if a user is a fan of my facebook page? Is it possible to track? - facebook

Question

I am trying to determine if a user is a facebook fan. I load the facebook JS library and initialize:
<script type="text/javascript" src="http://static.ak.connect.facebook.com/js/api_lib/v0.4/FeatureLoader.js.php/en_US"></script>
FB_RequireFeatures(["XFBML","Connect","Api"], function() { FB.init("my_api_key","xd_receiver.htm") });
FB.ensureInit(function () {
FB.ApiClient.pages_isFan(my_profile_id,"some_UID",callback);
});
However when I call the API client with FB.ApiClient.pages_isFan, I get a JS error -
FB.ApiClient is undefined
I am also using the FBML fan tag to display the "become a fan" button:
<fb:fan profile_id="my_profile_id" stream="0" connections="10" logobar="1" width="300"></fb:fan>
And would like to be notified when either the "become a fan" button is clicked or a user has successfully become a fan.
The business logic is pretty simple - If they become a fan, track it in my database. Then if they try to become a fan again, check with the library if they are a fan and say "You are already a fan" if they are a fan, show the widget if not.

Answer 1

Using the new JS SDK:
<fb:login-button perms="user_likes">
Grant Permissions to Allow access to Likes
</fb:login-button>
<button onclick="checkDoesLike()">Check if user Likes the Page</button>
<h1>Like this Application's Page</h1>
<fb:like-box profile-id="184484190795"></fb:like-box>
<script>
window.checkDoesLike = function() {
FB.api({ method: 'pages.isFan', page_id: '184484190795' }, function(resp) {
if (resp) {
Log.info('You like the Application.');
} else {
Log.error("You don't like the Application.");
}
});
};
</script>
A working example: http://fbrell.com/fb.api/does-like

Answer 2

Please note that #daaku's answer is true only in two cases:
If your app grant the user_likes permission or
The user's pages privacy setting is set to everyone.
Source:
Note: This call no longer requires a
session key. You must pass a user ID
if you don't pass a session key. If
the user's pages are set to less than
everyone privacy, you must ask the
user for the user_likes extended
permission and include a valid user
access token in the API call.
Try this code to better understand:
<button onclick="checkDoesLike()">Check if user Likes the Page (wrong way)</button>
<button onclick="checkDoesLike2()">Check if user Likes the Page (right way)</button>
<script>
window.checkDoesLike = function() {
FB.api({ method: 'pages.isFan', page_id: '184484190795', uid: '579187141' }, function(resp) {
if (resp) {
Log.info('579187141 likes the Application.');
} else {
Log.error("579187141 doesn't like the Application.");
}
});
};
window.checkDoesLike2 = function() {
FB.api({ method: 'pages.isFan', page_id: '184484190795', uid: '579187141' }, function(resp) {
if (resp == true) {
Log.info('579187141 likes the Application.');
} else if(resp.error_code) {
Log.error(resp.error_msg);
} else {
Log.error("579187141 doesn't like the Application.");
}
});
};
</script>
Working example.
I've also written a full tutorial about this today.

Answer 3

not sure if this is helpful at all, but I inspected the DOM with firebug and I found that it has moved onto the Facebook object
var pageID = 'your page';
var uid = FB.Facebook.apiClient.get_session().uid;
FB.Facebook.apiClient.pages_isFan(pageID, uid, function(result){ alert("boo!");});