$client_id = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'; // Client ID
$client_secret = 'XXXXXXXXXXXXXXXXXXXXXXX'; // Client secret
$redirect_uri = 'https://site.ru/social_login_callback/google.php'; // Redirect URI
$url = 'https://accounts.google.com/o/oauth2/auth';
$params = array(
'redirect_uri' => $redirect_uri,
'response_type' => 'code',
'client_id' => $client_id,
'scope' => 'https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile'
);
header('Location: '. $url . '?' . urldecode(http_build_query($params)) ); exit();