Check How to Login With Google Account OpenID in PHP

Here, is the tutorial about to do login with Google account OpenID in PHP. With using minimum line of PHP codes, we can collect required user information from Google, and use this information to register as well as login.

Create Sample Database Table :-

Sample database table with columns id, email, oauth_uid, oauth_provider and username.

CREATE TABLE users
(
id INT PRIMARY KEY AUTO_INCREMENT,
email VARCHAR(70),
oauth_uid int(11),
oauth_provider VARCHAR(100),
username VARCHAR(100)
);

Directory structure :-

Google-login    //Google logn OpenID library
    config
    --dbconfig.php
    --functions.php  
    google-open
    --openid.php

    images
    --googlebtn.png
 
    getGoogleData.php
    home.php
    index.php
    login-google.php
    logout.php    //Logout page

dbconfig.php :-

Connection file to connect with your database.

<?php

define('DB_SERVER', 'dbserver');
define('DB_USERNAME', 'username');
define('DB_PASSWORD', 'password');
define('DB_DATABASE', 'database');

define('USERS_TABLE_NAME', 'users_table_name');

$connection = mysql_connect(DB_SERVER, DB_USERNAME, DB_PASSWORD) or die(mysql_error());
$database = mysql_select_db(DB_DATABASE) or die(mysql_error());

?>

Function.php :-

<?php
include 'config/functions.php';

session_start();

if (!empty($_GET['openid_ext1_value_firstname']) && !empty($_GET['openid_ext1_value_lastname']) && !empty($_GET['openid_ext1_value_email'])) {  
    $username = $_GET['openid_ext1_value_firstname'] . $_GET['openid_ext1_value_lastname'];
    $email = $_GET['openid_ext1_value_email'];

    $user = new User();
    $userdata = $user->checkUserGoogle($uid, 'Google', $username, $email);
    if(!empty($userdata)) {
        session_start();
        $_SESSION['id'] = $userdata['id'];
        $_SESSION['oauth_id'] = $uid;

        $_SESSION['username'] = $userdata['username'];
        $_SESSION['email'] = $userdata['email'];
        $_SESSION['oauth_provider'] = $userdata['oauth_provider'];
        header("Location: home.php");

    } else {
        // Something's missing, go back to square 1
        header('Location: error.php');
    }

}
?>

Index.php Page :-

Add this code in
<?php
session_start();
if (isset($_SESSION['id'])) {
// Redirect to home page as we are already logged in
header("location: home.php");
}
if (array_key_exists("login", $_GET))
{
$oauth_provider = $_GET['oauth_provider'];
if ($oauth_provider == 'google')
{
header("Location: login-google.php");
}
}
?>

//HTML Code

<a href="?login&oauth_provider=google">Google Login</a>
Welcome Page

Name: <?php $_SESSIONS['username'] >
Email: <?php $_SESSIONS['email'] >
Your are logged in with: <?php $_SESSIONS['oauth_provider'] >
<a href="logout.php?logout">Logout</a> from  <?php $_SESSIONS['oauth_provider'] >