WordPress Page Template for SSO with Homeland

gistfile1.php

<?php
// Fork from: https://gist.github.com/adamcapriola/11300529
$sso_secret = 'meow';
$homeland_url = 'http://your-homeland-app.com'; // Note: No trailing slash!

if ( ! is_user_logged_in() ) {
	// Preserve sso and sig parameters
	$redirect = add_query_arg();

	// Change %0A to %0B so it's not stripped out in wp_sanitize_redirect
	$redirect = str_replace( '%0A', '%0B', $redirect );
	// Build login URL
	$login = wp_login_url( $redirect );
	// Redirect to login
	wp_redirect( $login );
	exit;
}
// Logged in to WordPress, now try to log in to Discourse with WordPress user information
else {
	// Payload and signature
	$payload = $_GET['sso'];
	$sig = $_GET['sig'];
	// Change %0B back to %0A
	$payload = urldecode( str_replace( '%0B', '%0A', urlencode( $payload ) ) );

	// Check for helper class
  // https://github.com/ArmedGuy/discourse_sso_php
	if ( ! class_exists( 'Discourse_SSO' ) ) {
		// Error message
		echo( 'Helper class is not properly included.' );
		// Terminate
		exit;
	}
	// Validate signature
	$sso = new Discourse_SSO( $sso_secret );
	if ( ! ( $sso->validate( $payload, $sig ) ) ) {

		// Error message
		echo( 'Invalid request.' );

		// Terminate
		exit;
	}
	// Nonce
	$nonce = $sso->getNonce( $payload );
	// Current user info
	get_currentuserinfo();
	// Map information
	$params = array(
		'nonce' => $nonce,
		'name' => $current_user->display_name,
		'username' => $current_user->user_login,
		'email' => $current_user->user_email,
		'about_me' => $current_user->description,
		'external_id' => $current_user->ID
	);
	// Build login string
	$q = $sso->buildLoginString( $params );
	// Redirect back to Homeland
	wp_redirect( $homeland_url . '/auth/sso/login?' . $q );
	exit;
}