Programmatically log in a wordpress user

Question

I am trying to programmatically log in a wordpress user, using the following function for that.

    public function auto_login( $user ) {
        $username = $user;
            if ( !is_user_logged_in() ) {
            $user = get_user_by( 'login', $username );
                wp_set_current_user( $user->ID, $user->user_login );
                wp_set_auth_cookie( $user->ID );
                do_action( 'wp_login', $user->user_login );
            }     
}

Unfortunately it seems not to be working. That function is called from within a shortcode. Could this be the explanation ? Should I rather hook my function to some filter, before any content is output ? Also I would like to redirect the newly logged in user to a specific post based on a $_GET parameter, can I simply add a header redirect at the end of the function ?

Thank you in advance for your help !

Answer 1

Do this on template_redirect hook. You can use wp_safe_redirect to redirect to different page in the blog. I can't give you the code because I don't from where you are getting the $user

Answer 2

You can try this function as it is working for me

function custom_login() {
    $creds = array();
    $creds['user_login'] = 'example';
    $creds['user_password'] = 'plaintextpw';
    $creds['remember'] = true;
    $user = wp_signon( $creds, false );
    if ( is_wp_error($user) )
        echo $user->get_error_message();
}
// run it before the headers and cookies are sent
add_action( 'after_setup_theme', 'custom_login' );

For details please visit the official site here