HttpSeoRedirect.php

<?php
/**
* The right way to do a SEO HTTP Redirection. (says me)
* 
* @copyright Claude "CodeAngry" Adrian
* @link http://codeangry.com/
* @license WTFPL
*/
namespace CA;

/**
* Redirection is permanent, resource moved.
*/
const HttpRedirect_Permanent = 301;

/**
* Redirection is temporary, resource still lives here.
*/
const HttpRedirect_Temporary = 302;

/**
* The right way to do a Redirection (SEO friendly and such).
* If returns false then you can't code!
* 
* @param string $URL
* @param int $StatusCode
* @return bool
*/
function HttpRedirect($URL, $StatusCode = 302){
	//<ARGS:VALIDATE>
	// Validate URL
	if(empty($URL)){
		$URL = $_SERVER['REQUEST_URI']; // Empty falls back to current
	}
	if(!is_string($URL) or !strlen($URL = trim($URL))){
		trigger_error('$URL has to be a proper string, you non-coder.', E_USER_WARNING);
		return false; // So bad it hurts!
	}

	// Validate Status Code
	if(empty($StatusCode)){
		$StatusCode = 302;
	}
	if(!is_numeric($StatusCode) or (intval(($StatusCode = intval($StatusCode)) / 100) != 3)){
		trigger_error('HTTP $StatusCode must be in 3##, you non-coder.', E_USER_WARNING);
		return false;
	}
	//</ARGS:VALIDATE>

	// <PLAN:A>
	// Do http redirect if headers are not sent
	if(!headers_sent()){
		header("Status: {$StatusCode} Relocated");
		header("{$_SERVER['SERVER_PROTOCOL']} {$StatusCode} Relocated");
		header("Location: {$URL}", $StatusCode);
	}
	// </PLAN:A>
	
	// <PLAN:B> - Truth is one should NOT get here!
	$URL_Escaped = htmlentities($URL); // For HTML tag output
	if($StatusCode == 301){
		// Do a rel=canonical if the HTTP 301 failed due to sent headers (similar effect for crawlers)
		echo '<link rel="canonical" href="', $URL_Escaped, '"/>', PHP_EOL;
	}
	// Try to redirect with JS
	echo '<script type="text/javascript">',
		'window.location.href="', $URL, '";',
		'</script>', PHP_EOL;
	// Try to redirect Meta Redirect
	echo '<meta http-equiv="refresh" content="0;url=', $URL_Escaped, '" />', PHP_EOL;
	// </PLAN:B>
	
	
	// <PLAN:C> - Truth is one should NEVER get here!
	// Try to redirect with User
	echo '<div><a href="', $URL_Escaped, '">', $URL_Escaped, '</a></div>';
	// </PLAN:C>

	return true;
}

/**
* Alias of HttpRedirect($URL, 302);.
* 
* @param string $URL
* @return bool
*/
function HttpRedirected($URL){
	return HttpRedirect($URL, 302);
}

/**
* Alias of HttpRedirect($URL, 301);.
* 
* @param string $URL
* @return bool
*/
function HttpMoved($URL){
	return HttpRedirect($URL, 301);
}
?>