Get Facebook user email upon registration

Question

I'm trying to allow users to register on my web application via Facebook. As part of my normal registration users must supply their email address, and I need to include this as part of the Facebook registration.

I am using the code below, which works correctly, except it doesnt return the user email address as part of Facebook's response. I am aware I need to specifically "ask" for the email, but I'm confused where/how I do this in my code below?

I am also aware a user may choose to not supply their email address as part of the process, but I'm able to handle that.

    // Grab our facebook details
    $app_id = $this->config->item('fb_app_id');
    $app_secret = $this->config->item('fb_secret_key');
    $my_url = $this->config->item('fb_url');

    session_start();

    if(isset($_REQUEST["code"]))
    {
        $code = $_REQUEST["code"];
    }
    else
    {
        $_SESSION['state'] = md5(uniqid(rand(), TRUE)); //CSRF protection
        $dialog_url = "https://www.facebook.com/dialog/oauth?client_id=" 
        . $app_id . "&redirect_uri=" . urlencode($my_url) . "&state="
        . $_SESSION['state'];
        echo("<script> top.location.href='" . $dialog_url . "'</script>");
    }

    if ((isset($_REQUEST['state'])) && (($_REQUEST['state'] == $_SESSION['state'])))
    {
        $token_url = "https://graph.facebook.com/oauth/access_token?"
        . "client_id=" . $app_id . "&redirect_uri=" . urlencode($my_url)
        . "&client_secret=" . $app_secret . "&code=" . $code;

        $response = file_get_contents($token_url);
        $params = null;
        parse_str($response, $params);

        $graph_url = "https://graph.facebook.com/me?access_token=". $params['access_token'];

        $user = json_decode(file_get_contents($graph_url));
        if ( ! empty($user))
        {
                            // NO EMAIL HERE?!
            $email = strtolower($user->email);


        }
    }

score 2 · Accepted Answer · edited May 23 '17 at 12:20

2

Looks like this has been asked before. The answer can be found here:

Facebook Graph API, how to get users email?

edited May 23 '17 at 12:20

Community

1
1

answered Jun 20 '12 at 09:29

Socken Puppe

134
3

thanks - I saw that - but I was confused where to include the 'scope' for email in my code above? I'll have another look... – Laurence Jun 20 '12 at 09:36

score 0 · Answer 2 · answered Jun 20 '12 at 10:52

This code works for me...Hopefully it will work well for you also

define('FACEBOOK_APP_ID', 'YOUR_APP_ID_HERE'); define('FACEBOOK_SECRET', 'YOUR_APP_SECRET_HERE');

        // No need to change function body
        function parse_signed_request($signed_request, $secret) {
            list($encoded_sig, $payload) = explode('.', $signed_request, 2);

            // decode the data
            $sig = base64_url_decode($encoded_sig);
            $data = json_decode(base64_url_decode($payload), true);

            if (strtoupper($data['algorithm']) !== 'HMAC-SHA256') {
                error_log('Unknown algorithm. Expected HMAC-SHA256');
                return null;
            }

            // check sig
            $expected_sig = hash_hmac('sha256', $payload, $secret, $raw = true);
            if ($sig !== $expected_sig) {
                error_log('Bad Signed JSON signature!');
                return null;
            }

            return $data;
        }

        function base64_url_decode($input) {
            return base64_decode(strtr($input, '-_', '+/'));
        }

        if ($_REQUEST) {
            $response = parse_signed_request($_REQUEST['signed_request'],
                            FACEBOOK_SECRET);
            /*
            echo "<pre>";
            print_r($response);
            echo "</pre>"; // Uncomment this for printing the response Array
            */

            $email = $response["registration"]["email"];

Get Facebook user email upon registration

2 Answers2