<?php
	require("mysql.php"); // to establish a connection to the db
	
	/* configurations options */
	
	$lengthOfTheHash = 5; // the length determine the numbers of chars in the hash created 5 => 12345 for example
	$timeToExpire = 1; // in days
	$urlOfYourSite = "http://www.djpate.com/portfolio/shortURL";
	
	function createHash($length=5){ // very simple hash function to generate a random string
	$valid = 0;
		while(!$valid){
			for($i=0;$i<$length;$i++){
				$possibleValues = "123456789"; // if you want to add letters you will have to change the id to varchar instead of int
				 // pick a random character from the possible ones
	    		$hash .= substr($possibleValues, mt_rand(0, strlen($possibleValues)-1), 1);
			}
		$check = mysql_query("select id from urls where id = $hash") or die(mysql_error()); // checks if the hash allready exists in the db , not very likely to happen
		if(mysql_num_rows($check)==0){
			$valid = 1;
		}
		}
		return $hash;
	}
	
	if(isset($_POST['url'])){ // post was posted
		//here we want to validate that the url is valid with a regexp
		if(ereg("^http\://[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(/\S*)?$",$_POST['url'])){
			$hash = createHash();
			mysql_query("insert into urls (id,url,expire) values ($hash,'".addslashes($_POST['url'])."',date_add(now(),interval $timeToExpire day))") or die(mysql_error());
			echo "Congrats ! here is your link : <a href=\"$urlOfYourSite/v/$hash\">$urlOfYourSite/v/$hash</a>";
		} else {
			echo "Invalid url !";
		}
	} else {
		// no post data so we display the form
		?>
		<form method="post">
			URL : <input type=text name=url>
			<input type=submit value=go>
		</form>
		<?php
	}
?>