facebook

Facebook Connect Tutorial

THIS TUTORIAL IS VERY OLD, AND PROBABLY IT WILL NOT WORK ANYMORE, HERE IS THE NEW VERSION.

This tutorial will guide you to the process of integration of your web community with Facebook. This means that when a visitor comes to your site it can log in with normal credenditals if it has, but if it has not it can click on the “facebook connect” button and try to log in with its facebook account, automatically.

This is a good thing because, of course, your community is not so big and famous that every visitor wants to register and become a user to leave just a comment, but probably your visitors already have a Facebook account. So why loose their comments?
More: you can use facebook connected users to post automatically on users’s facebook walls, that is to say, you can increase your traffic.

The target is to add facebook connect functionality with small changes to your code, we also want to make very small changes to your database and to your normal login process.

INDEX, SEVEN STEPS:
1. Create an application on Facebook
2. Copy on your site the xd_receiver.htm file
3. Download the PHP apis for facebook and copy them to your site
4. Modify your users’ table
5. Create a PHP page for log in with facebook connect
6. Link the fbclogin.php file to your login
7. Further implementations in the next posts/pages of this blog

So let’s start:

STEP 1. Create an application on Facebook

This means that you have to be registered and logged-in on Facebook, than you have to go to the developer page on facebook and click on the “set up new application” button.
In the set up page you have different fields to enter, but only these ones are needed to make a facebook-connect application for our purpose:
a. “name of the application” and your developer contact in the Main Panel;
b. “Connect url” in the Facebook Connect Panel, you should enter the root of your community site, for the example: http://www.your-site-url.com
c. you can customize log (not necessary)

Save the changes.
This will create a couple of keys that you will use inside your PHP login page: API Key and secret. Copy them or leave this window open to copy them later.

STEP 2. Copy on your site the xd_receiver.htm file

This file is also called “cross domain communication channel” and it’s a static file which include some javascript from facebook servers. The job of this file is set up cookie of Facebook on your domain. It’s necessary because cookies are linked to the domain of the site that write them, so Facebook cannot add cookies on your site without this. And cookies are necessary because the PHP script that will do the work will read cookies setted up by this file. Your site will call facebook, facebook will ask for password if the user isn’t yet logged in, and facebook will call xd receiver to set up cookies on your domain. Finally PHP script will read the cookie that say “logged on facebook ok!”.

Here is the xd receiver file: (you can find it here)


Cross-Domain Receiver Page

<script type="text/javascript" src="http://static.ak.connect.facebook.com/js/api_lib/v0.4/XdCommReceiver.js?2"></script>

STEP 3. Download the PHP apis for facebook and copy them to your site You can download the PHP API here on Github server. You can find the previous link in the get started page of Facebook developers page. STEP 4. Modify your users’ table This is important: we want to let connect the guys of facebook, but we also want to make new users, so we create new users on our community for every new guy coming from facebook. We suppose that you already have a users’ table on your db:

TABLE users (something like this):

id	ID INT AUTOINCREMENT PRIMARY
username	VARCHAR
password	VARCHAR
email		VARCHAR
status		ENUM ('active','pending','deactivated')
activationdate	DATETIME

If you have the primary key on the email field, than you will have to remove it and use an autoincrement key because you will not receive the email from facebook, the users coming from facebook do not have the email field filled at the beginning. So they are “different”. Add those fields to your users table:

fb_userid	VARCHAR
fl_facebook	ENUM ('new','normal','registered') DEFAULT = 'registered'

the fb_userid will store the facebook user id. the fl_facebook is a flag and the values can be: registered = is the default value that identify your users normally registered on your db new = for new users just created normal = for users that have been transformed into normal users (this could happen later, when you will ask the email to those users to make some action that only registered users can make on your site… for example buy a thing, subscribe to a newsletter, create a new item…), when they become ‘normal’ they are no longer ‘different’. STEP 5.create a PHP page for log in with facebook connectHere it is the code of the facebook login file (fbclogin.php), put it on your web site root (below some note) and read it because it’s full of comments:

<script type="text/javascript" src="http://static.ak.connect.facebook.com/js/api_lib/v0.4/FeatureLoader.js.php"></script>

get_loggedin_user();

$out="";
if($fb_user) {
 //
 // if we already have a user ID cookie than we link
 // in the database this user with his facebook account
 // using the fb_userid field.
 // this code assumes that when a user login in your
 // community you set up a value in a cookie called "myid".
 // this cookie is the one that you use when you want
 // to remember the user:
 if ($_COOKIE["myid"]) {
 //$rs = mysql_query( "select * from users where id <>'".$_COOKIE["myid"]."' and fb_userid='".$fb_user."'" );
 //$r = mysql_fetch_array($rs);
 mysql_query("update users set fb_userid='{$fb_user}' where id='".$_COOKIE["myid"]."'");
 }
 //
 // with the user id from facebook retrived with the API,
 // search for a user already registered with this process:
 $rs = mysql_query( "select * from users where fb_userid='$fb_user'" );
 if (mysql_num_rows($rs)) $u = mysql_fetch_array($rs); else $u="";
 if (is_array($u)) {
 //
 // this is a user connected with facebook
 // and already existing on your community.
 // So, log in automatically with user and password of
 // your community. These lens print a form and submit it
 // to your real login page:
 // (change the address in the action to match your normal login page)
 $out.="log in...";
 $out.="</pre>
<form id="loginform" action="\&quot;http://www.your-site-url.com/login.php\&quot;" method="post">";
 $out.="<input type="hidden" name="user" value="\&quot;&quot;.$u['username'].&quot;\&quot;/" />";
 $out.="<input type="hidden" name="pass" value="\&quot;&quot;.$u['password'].&quot;\&quot;/" />";
 $out.="</form>
<pre>
";
$out.="<script type="\&quot;text/javascript\&quot;">// <![CDATA[
document.getElementById('loginform').submit();
// ]]></script>";

 } else {
 //
 // this is a user logged in on facebook
 // but it doesn't exists on your community,
 // it's new!
 // So let's create automatically the user and log in!
 $out = '';
 //
 // get some user details from facebook api
 $user_details = $fb->api_client->users_getInfo($fb_user, array('last_name','first_name'));
 //
 // write out some message to welcome the new user:
 $out.= $user_details[0]['first_name']." ".$user_details[0]['last_name'].", welcome on your-site-url.com
";
 $out.= "creating your account on your-site-url.com... wait...";
 $tempuser = preg_replace("/[^a-z0-9]/i","",strtolower( $user_details[0]['first_name'].$user_details[0]['last_name'] ));
 $found = false;
 $i=0;
 while (!$found) {
 //
 // search for a valid username
 // not already used in your community
 // this username is created with first name and last name
 // from facebook and with a counter:
 $user = $tempuser.($i==0?"":$i);
 $rs = mysql_query("select count(*) from users where username='$user'");
 $c = mysql_fetch_row($rs);
 if ( $c[0] >0 ) $i++; else $found = true;
 }
 //
 // generate random password for new user:
 $pass = "fb".rand(1000,2000);
 //
 // empty email:
 $email = "";
 //create the user on your table
 $sql = "INSERT INTO users (" .
 "username, password, name, surname, email, status, activationdate, fb_userid, fl_facebook".
 ") VALUES ('{$user}','{$pass}','".addslashes($user_details[0]['first_name'])."',".
 "'".addslashes($user_details[0]['last_name'])."','".$email."',".
 "'active',NOW(),'','".
 $fb_user."','new')";
 mysql_query($sql);
 //
 // new user created, log him in:
 $out.="log in...";
 $out.="</pre>
<form id="loginform" action="\&quot;http://www.your-site-url.com/login.php\&quot;" method="post">";
 $out.="<input type="hidden" name="user" value="\&quot;&quot;.$user.&quot;\&quot;/" />";
 $out.="<input type="hidden" name="pass" value="\&quot;&quot;.$pass.&quot;\&quot;/" />";
 $out.="</form>
<pre>
";
$out.="<script type="\&quot;text/javascript\&quot;">// <![CDATA[
document.getElementById('loginform').submit();
// ]]></script>";
 }
} else {
 //
 // the user probably isn't logged in on facebook, put out
 // the facebook button and clicking on it it will open a pop uo
 // that requires the login on facebook to proceed.
 // the "onlogin" command refresh the page.
 $out = '
 Click to log on your-site-url.com with your facebook account.

';
}
?>
<!--?=$out? -->
<script type="text/javascript">// <![CDATA[
  FB.init("<?=FB_API_KEY?>", "/xd_receiver.htm");
// ]]></script>

This PHP file includes in the header some tag for facebook (the namespace declaration in the html tag), so it can handle FBML code (the facebook specific tags for html facebook elements).
Than it includes a javascript file from facebook which is called at the end with FB.init javascript call.

STEP 6. Link the fbclogin.php file to your login

Near your login fields, add a link to the fbclogin.php file so users will notice suddenly that you give a facebook connect functionality.

STEP 7. further implementations in the next posts

a. copy the avatar from facebook to your server: it’s easy: note, this is not approved by Facebook policies!
b. handle redirect to the correct page: if you have the login in every page you can modify this code to let the user go back to the correct page after the login process.
c. handle duplicated accounts: sometimes a user that connect with facebook already has an account on your site, so you will have two users for the same person on your db. That could be a problem, we will explain why and how to solve the problem.
d. handle registration completed: registration is completed when a user give you every data you consider mandatory, such as the email. This script already handles the flag fl_facebook, but in a further post we will explain how to modify your scripts to handle this part of the process.
e. use facebook connect functions to post to users wall on facebook: this will increase traffic to your site.

Anything to say?

Comments with Facebook or below with WordPress



WordPress comments:

  1. Hi. Please can you help me out. I am getting this error: Parse error: syntax error, unexpected T_INC in /home/gtownco/public_html/fbclogin.php on line 85
    Thank you.

  2. yes. It’s missing a $. Change i++ with $i++.
    there is also another errror in this line, I miss an “else”. Change the line this way:

    if ( $c[0] >0 ) $i++; else $found = true;
    

    I’ve fixed it in the post.

  3. Hi, can you please give an example for the settings-and-functions.php?

    It would be great because I am new to PHP and do not know the syntax yet.

    Thanking you in anticipation.

  4. It’s just a file with at least those lines:

    <?
    DEFINE("FB_API_KEY" , "value from facebook application setting");
    DEFINE("FB_SECRET" , "value from facebook application setting");
    function ConnectDB() {
    if (mysql_connect( "domain", "user", "pwd" ) && mysql_select_db( "yourdb" )) return 1;	else return 0;
    }
    ?>
    

    you’re really a beginner! :-)

  5. C’è una versione del tutorial in italiano ?
    Ho seri problemi con l inglese, anche se lo traduco con google translate non capisco lo stesso.

  6. Hi,
    Thanks a lot for your tutorial!

    I have a problem: when i go to fbclogin.php I have the followings error:

    Fatal error: Call to undefined function connectdb() in /home/namesite/public_html/forum/fbclogin.php on line 16

    In line 16 there is “if(!ConnectDB()) die;”, what means it?

    Thanks a lot for your support

  7. Settings and functions is a file that you have to write by yourself, this file should include at least the connectDB function to connect to your database and everything you need to work with your db.

  8. Great post! Any more info on..

    “c. handle duplicated accounts: sometimes a user that connect with facebook already has an account on your site, so you will have two users for the same person on your db. That could be a problem, we will explain why and how to solve the problem.”

  9. Hello! About these two lines:

    You can download the PHP API here on Facebook servers.
    You can find the previous link in the get started page of Facebook developers page.

    The first line is a dead link. The second one takes me to a page but I don’t understand what I am supposed to download. Could you please maybe update the link? Thank you very much

  10. wow, just works for first user, second time don’t insert on database, any idea how to fix it?

  11. Can you provide some help with disconnecting from Facebook? It seems no matter what example I try from searching Google, nothing logs out of Facebook. I am looking for something to put in my logout.php page and redirect it to login.php. FB.Connect.logoutAndRedirect doesn’t seem to do ANYTHING.

    Thanks!

  12. Nevermind, I found something that works perfectly:

    window.onload = function(){
    FB.Facebook.init(‘my_facebook_api_key’,’/xd_receiver.html’);
    FB.Connect.logout(function(){
    // we are logged out of facebook, erase my app’s cookie
    var name = “name_of_my_session_cookie”;
    document.cookie = name +’=;expires=Thu, 01-Jan-1970 00:00:01 GMT’;
    //refresh the main page
    var url = window.parent.location.href;
    // append a timestamp to make sure the url seems different to the browser
    url = (url+(url.indexOf(‘?’) > -1 ? ‘&’ : ‘?’)+(new Date()).getTime());
    window.parent.location.href = url;
    });
    };
    Found at http://forum.developers.facebook.com/viewtopic.php?pid=119774#p119774

    :)

  13. im missing the point at line 34 of the main script

    i assume this line connect my facebook user to my currenty logged user

    that way… the query returns 0 lines, maybe you should check with an = for the cookie-user_id pair and with for the fb_userid

  14. You’re right! Sorry for that error. You can remove line 34 and 35 (I’ve commented) because they are part of a solution for the problem described in STEP 7, part C. I’ve not yet posted it.

  15. MMmm since with this tutorial I bring the users to create a new account on my site… I don’t matter if they are still logged in into facebook. Or not?

  16. ciao, ho un sito ma non riesco ad integrare perfettamente facebook connect, perché non so o bravissimo!!!

    qualcuno può darmi una mano!??!?

    sapete come poter far accedere al sito anche con un account google??

    grazie

  17. Como hago para solucionar el paso 7 C), para no tener usuarios duplicados en mi base de datos. Muchas gracias.

  18. getting this error
    Fatal error: Call to undefined method Facebook::get_loggedin_user() in C:\xampp\htdocs\testing\facebookconnect\fb_connect\connect\fbclogin.php on line 21

  19. Vicky you have to implement by yourself that part, this code is not “ready to use”, but you have to customize it on your needs. That id stored in the cookie is the id of your user when it normally log in (you should have a mechanism that handle logged in user id).

  20. Vicky….
    Had the same problem myself. Found a quick fix for it.

    Change line 21 from:

    $fb_user=$fb->get_loggedin_user();

    to

    $fb_user=$fb->getUser();

    That should fix the error.

  21. Quick question for you Giullo…..

    I’m trying to request extended permissions from Facebook, but no matter where I put the perms=”email,user_birthday,etc…” line, it won’t take it. I put a “req_perms” argument in the seemingly designated place (as noted by a comment in the code) in facebook.php and it still won’t take. I just get the same old “**** is requesting to do the following: access my basic information” when I click the connect button displayed on fbclogin.php.

    Any ideas?

    Thanks.

  22. I am gettin this error!!

    Fatal error: Cannot redeclare class FacebookApiException in D:\wamp\www\books\connect\facebook.php on line 70

    Pls help me :(

  23. Fatal error: Call to undefined method Facebook::get_loggedin_user() in D:\wamp\www\books\connect\fbclogin.php on line 21

    PLS HELP ME :(

  24. Step 1 is outdated or something
    you say: “Connect url” in the Facebook Connect Panel

    But nowhere on the application creation do either of these things exist?!

    So i cannot go past the first few lines of your wonderful tutorial

    Have facebook changed?

  25. Just some friendly advice,

    I just spent over 2 hours trying to get this working without any luck,
    You might wanna write something like “THIS DOES NOT WORK ANYMORE, FACEBOOK HAS CHANGED” at the top of the page. Or update the content so it will work.

    Thanks,

  26. Claro que si funciona, yo lo hice para conectarse con mi red social directamente desde tu perfil de facebook, si quieren vean y se convencerán: http://directorio.a60.us/jcow/ dice conectar básico y con facebook, así que amigo de verdad te agradezco por tan valioso aporte que me sacó de apuros. Los que no saben inglés sugiero que utilicen el navegador de google chrome que viene integrado con un traductor automático

  27. It still works for me, but probably it doesn’t works with
    new facebook applications. If you have an old Facebook connect
    application it works, if you’ve registered an application recently
    I think it will not work.

  28. Hi All

    I have just created an app on facebook and want to try exactly the same thing as mentioned in the tutorial , but i read the comments and see that this is quite old and might not work for recently creates apps.

    can someone please give any pointer to some other tutorial or guide for facebook connect to work in website?

    PLS HELP !!!

    debjani

  29. I can see you’re an expert at your field! I am launching a website soon, and your data will likely be really useful for me.. Thanks for all your assist and wishing you all of the success.

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  36. I think you have to read the facebook documentation, since this page became old and it seems it doesn’t work anymore.

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  40. i cannot find settings-and-functions.php
    it gives me errors

    Warning: include(settings-and-functions.php) [function.include]: failed to open stream: No such file or directory in C:\AppServ\www\phase2.3\fbclogin.php on line 10

    Warning: include() [function.include]: Failed opening ‘settings-and-functions.php’ for inclusion (include_path=’.;C:\php6\pear’) in C:\AppServ\www\phase2.3\fbclogin.php on line 10

    Fatal error: Call to undefined function ConnectDB() in C:\AppServ\www\phase2.3\fbclogin.php on line 16

  41. Warning: include(settings-and-functions.php) [function.include]: failed to open stream: No such file or directory in C:\AppServ\www\phase2.3\fbclogin.php on line 10

  42. Question: so, if I access someone’s FB site this way (php), they essentially can monitor who is viewing their site in this manner? In other words, they can see how many times I or someone else accesses their site?



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