andykillen/page-quizredirect.php

## page-quizredirect.php
<?php
/**
* Template Name: Facebook quiz redirect
*
**/

function check_if_facebook(){
  /**
  * this function checks if the current thing accessing the site is a facebook
  * bot or not.
  **/
  $is_facebook = false;

  $pattern = '/(FacebookExternalHit|visionutils|Facebot)/i';
  $agent = filter_input(INPUT_SERVER, 'HTTP_USER_AGENT', FILTER_SANITIZE_ENCODED);
  if(preg_match($pattern,$agent)){
    $is_facebook = true;
  }
  /**
  * Returns TRUE if is facebook bot, FALSE is anybody else
  **/
  return $is_facebook;
}

/**
* Check if the response if false and redirect if needed
* The redirect using header() must happen before get_header() is called
* If not, it will not work as things will already be sent to the browser/bot
**/
if( ! check_if_facebook() ){
  header("Location:" . get_bloginfo('url') . "/quiz");
}

/**
* load get_header() so that all of the Open Graph info is added into the <head>
**/
get_header();

/**
* Loop not needed as facebook reads the head section only
*
* Footer not really needed, but left in for clarity
**/

get_footer();
	<?php
	/**
	* Template Name: Facebook quiz redirect
	*
	**/

	function check_if_facebook(){
	/**
	* this function checks if the current thing accessing the site is a facebook
	* bot or not.
	**/
	$is_facebook = false;

	$pattern = '/(FacebookExternalHit\|visionutils\|Facebot)/i';
	$agent = filter_input(INPUT_SERVER, 'HTTP_USER_AGENT', FILTER_SANITIZE_ENCODED);
	if(preg_match($pattern,$agent)){
	$is_facebook = true;
	}
	/**
	* Returns TRUE if is facebook bot, FALSE is anybody else
	**/
	return $is_facebook;
	}

	/**
	* Check if the response if false and redirect if needed
	* The redirect using header() must happen before get_header() is called
	* If not, it will not work as things will already be sent to the browser/bot
	**/
	if( ! check_if_facebook() ){
	header("Location:" . get_bloginfo('url') . "/quiz");
	}

	/**
	* load get_header() so that all of the Open Graph info is added into the <head>
	**/
	get_header();

	/**
	* Loop not needed as facebook reads the head section only
	*
	* Footer not really needed, but left in for clarity
	**/

	get_footer();