Link login of two completely separate wordpress websites - wordpress

Question

I have two wordpress websites running on sub-domain of a server like http://first.mywebsites.net and http://second.mywebsites.net
They both are just like private sites, I can see the content of pages if I am logged in to the website otherwise redirected to the login page.
Now what I want is, if I am log in my first website and go to the link of second website in same browser then I am able to see the content of pages as a logged in user.
This must be happen only in a case when the user which is logged in first website having the same user(user registered with same mail id) in database of second website. As in case of my website, mostly users are registered with same mail id in both the websites.
Trying to achieve this by two approaches but still unable to get this by any of them :
Approach 1 : Adding a table to second website and save the user email and a auth key. Using curl to fetch the details and then logged in. This Approach is as mentioned in here : http://carlofontanos.com/auto-login-to-wordpress-from-another-website
But as I have mentioned it previous, that both the website is in my case are having private content, so in this case I am unable to fetch the details using curl. My code for curl is like :
$api_url = "http://second.mywebsites.net/autologin-api/";
// If you are using WordPress on website A, you can do the following to get the currently logged in user:
global $current_user;
$user_email = $current_user->user_email;
// Set the parameters
$params = array(
'action' => 'get_login_key', // The name of the action on Website B
'key' => '54321', // The key that was set on Website B for authentication purposes.
'user_email' => $user_email // Pass the user_email of the currently logged in user in Website A
);
// Send the data using cURL
$ch = curl_init($api_url);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($params));
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$gbi_response = curl_exec($ch);
curl_close($ch);
// Parse the response
parse_str($gbi_response);
print_r($gbi_response);
In this case I am not getting the response, My page redirect me to the login page of second website.
Approach 2 : Trying to do it with the use of cookies as I want to logged in to second website in same browser.
I have added a new cookie in my first website like :
global $current_user;
$user_email = $current_user->user_email;
if($user_email != ''){
$_COOKIE['current_user_mail_id'] = $user_email;
}
echo "<pre>";
print_r($_COOKIE);
echo "</pre>";
and added cookie is showing with the other cookies. But when I am checking this in my second website on same browser like :
echo "<pre>";
print_r($_COOKIE);
echo "</pre>";
The cookie which I have added in my first website is not showing on my second website.
I am not much familiar with cookies, setting auth cookies etc.
Please suggest a solution, how can I achieve this.

Answer 1

You can accomplished by using "Single Signon".
Instruction-
To simplify passing users between our systems I have created this PHP class
that you are welcome to use.
To check if a user is signed in:
$signon = new SingleSignon();
$userId = $signon->checkCookie();
if($userId){
// user is logged in and this is their id
}
else{
// user is not logged in or they are exipred
}
If the user is not logged in then use our api to login then use the following code if the api call is successful.
To set a user as logged in:
$signon = new SingleSignon();
$signon->setCookie($userId);
NOTE: You need to be using ssl for the cookie to be read.

Answer 2

I have gone through the solution provided by Gaurav and find a idea to make this possible for wordpress websites.
Place below mentioned code at the place where you want to put the link to go to your second website :
<?php global $current_user;
$user_email = $current_user->user_email;
$user_login = $current_user->user_login;
if($user_email != ''){
$email_encoded = rtrim(strtr(base64_encode($user_email), '+/', '-_'), '=');
$user_login_encoded = rtrim(strtr(base64_encode($user_login), '+/', '-_'), '=');
echo '<div class="dtNode">Link to second website</div>';
}?>
Now prepare a sso.php file and place it to the root installation of your second site where you want to logged in automatically. Now put the below code there :
<?php
require_once( 'wp-load.php' ); //put correct absolute path for this file
global $wpdb;
if(isset($_GET['key']) && !empty($_GET['key'])){
$email_decoded = base64_decode(strtr($_GET['key'], '-_', '+/'));
$username_decoded = base64_decode(strtr($_GET['detail'], '-_', '+/'));
$received_email = sanitize_text_field($email_decoded);
$received_username = sanitize_text_field($username_decoded);
if( email_exists( $received_email )) {
//get the user id for the user record exists for received email from database
$user_id = $wpdb->get_var($wpdb->prepare("SELECT * FROM wp_users WHERE user_email = %s", $received_email ) );
wp_set_auth_cookie( $user_id); //login the user
wp_redirect( 'http://second.mywebsites.net');
}else {
//register those user whose mail id does not exists in database
if(username_exists( $received_username )){
//if username coming from first site exists in our database for any other user,
//then the email id will be set as username
$userdata = array(
'user_login' => $received_email,
'user_email' => $received_email,
'user_pass' => $received_username, // password will be username always
'first_name' => $received_username, // first name willl be username
'role' => 'subscriber' //register the user with subscriber role only
);
}else {
$userdata = array(
'user_login' => $received_username,
'user_email' => $received_email,
'user_pass' => $received_username, // password will be username always
'first_name' => $received_username, // first name willl be username
'role' => 'subscriber' //register the user with subscriber role only
);
}
$user_id = wp_insert_user( $userdata ) ; // adding user to the database
//On success
if ( ! is_wp_error( $user_id ) ) {
wp_set_auth_cookie( $user_id); //login that newly created user
wp_redirect( 'http://second.mywebsites.net');
}else{
echo "There may be a mismatch of email/username with the existing record.
Check the users with your current email/username or try with any other account.";die;
}
}
die;
} ?>
Above code works for me, you can modify the code as per your needs. For more clear explanation, you can check here : http://www.wptricks24.com/auto-login-one-website-another-wordpress