====== REST Authentication ======

Locked channels require client side authentication in order to reveal their playlists. For this you need to dynamically create a link to a specific channel resource. Below please find an PHP4 coding example which should also be easily transferable to other programming languages. \\

(more to come)
 

<code>
<?php

$auth = new feedbeat_auth('http://demo.feedbeat.com/authdemo/', 99999);
echo $auth->get_url();

class feedbeat_auth {


	var $public_key = '47fc6879dade0';
	var $secret_key = '33eb1c2440947275cb58c769fad171e8';
	
	var $url = '';
	var $time = 0;
	var $expires = 0;
	
	/* local authentication */				
	function feedbeat_auth($url, $expires)
	{
				
		$this->url = $url;
		$this->time = time() + $expires;		
		$this->signature = rawurlencode($this->base64($this->hasher("$this->time\n$url", $this->secret_key)));	
		
		return true;
	
	}	



	function get_url() {
		
		return sprintf('%skeyid/%s/exp/%s/sig/%s/', $this->url, $this->public_key, $this->time, urlencode($this->signature));
	}

	function get_array() {
		
		return  array('keyid'=>$this->public_key,'exp'=>$this->time,'sig'=>$this->signature);
	}



	function hasher($data, $key)
	{
		// Algorithm adapted (stolen) from http://pear.php.net/package/Crypt_HMAC/)
		if(strlen($key) > 64)
			$key = pack("H40", sha1($key));
		if(strlen($key) < 64)
			$key = str_pad($key, 64, chr(0));
		$ipad = (substr($key, 0, 64) ^ str_repeat(chr(0x36), 64));
		$opad = (substr($key, 0, 64) ^ str_repeat(chr(0x5C), 64));
		return sha1($opad . pack("H40", sha1($ipad . $data)));
	}
	
	
	
	function base64($str)
	{
		$ret = "";
		for($i = 0; $i < strlen($str); $i += 2)
			$ret .= chr(hexdec(substr($str, $i, 2)));
		return base64_encode($ret);
	}


	
}
?>
</code>