YouTube/ TinyURL style unique id strings?

PHP
1

Hi,

Has anyone got a suggestion on how to could go about scripting YouTube/ TinyURL style unique id strings for use with PHP and MySQL, for example…

I was considering using a set of random numbers based on date and seconds - but it’d be great to use something similar to above.

Thanks,

Charlie

2

tinyurl started from 1. http://tinyurl.com/1 is a page about unicycles!

You “just” need a function to convert base 10 to base 36 (0-9 + a-z) - I did write this once, but can’t find it right now.

Mike

3

How about something like this…


<?php
// $previous_entry would be pulled from a database or something in a real-life situation.
$previous_entry = "afs";
// Generates the next string in alphabetical order (in this case, "aft" as "t" follows "s").
$new_entry = $previous_entry++;
// Prints the new string to the browser ("aft").
echo $new_entry;
?>

It could be done as simple as that. You could use integers or strings (letters or numbers). To test the behaviour of this as more entries are created, run this script…


<?php
$previous_entry = "afs";
// Prints the 10000 strings which would follow "afs".
while ($count < 10000) {
	echo $previous_entry."<br />";
	$previous_entry++;
	$count++;
	}
?>

You should now get an idea of the simplicity. Tinyurl would be one of the easiest applications to program. Just retrieve the most recent entry to the url database and plus it by 1 and then store that with the new URL. Rinse and repeat.

4

Interesting solution … the first few lines of that last script produce:

afs
aft
afu
afv
afw
afx
afy
afz
aga
agb
agc
agd

after the ‘z’ it rolls around to ‘a’. Shame it doesn’t use letters and numbers.

Usable as it is, though.

Mike

5

http://www.php.net/base_convert

Hope it helps!

6

yeah, base_convert()

I just wrote this exact thing for work.

the script is called like url.php?1ab3k

<?php
function encode36($x){
	return base_convert($x, 10, 36);
}
function decode36($x){
	return base_convert($x, 36, 10);
}



if(isset($_GET)){
	list($shortcode, $junk) = each($_GET);
	$id=decode36($shortcode);
	if(is_numeric($id)){
		$sql="select url from short where id=$id";
		$rs=mysql_query($sql);
		if(mysql_num_rows($rs)>0){
			$r=mysql_fetch_assoc($rs);
			header("Location: ".((substr($r['url'],0,7)=="http://" or substr($r['url'],0,8)=="https://")?"":"http://").$r['url']);
			exit;
		}
	}
}

header("Location: http://www.base-website.com");
exit;
?>

short.php makes the links


<?php
function encode36($x){
	return base_convert($x, 10, 36);
}

echo "
<form action='short.php' method='post'>
Your URL to Shorten: <input type=text name='url' value='http://' size=40> <input type=submit value='Submit'>
</form><br>";
if(isset($_POST['url']) and strlen($_POST['url'])>0 and (!stripos($_POST['url'],"url.php") or stripos($_POST['url'],"url.php")===false)){
	$url=mysql_escape_string($_POST['url']);
	$sql="select id from short where url='$url'";
	$rs=mysql_query($sql);
	if(mysql_num_rows($rs)>0){
		$r=mysql_fetch_assoc($rs);
		echo "Here's your short url: <b>http://www.base-website.com/url.php?".encode36($r['id'])."</b><br><small>(Shortened from: ".$url.")</small>";
	}else{
		$sql="insert into short (url) values ('$url')";
		mysql_query($sql);
		echo "Here's your short url: <b>http://www.base-website.com/url.php?".encode36(mysql_insert_id())."</b><br><small>(Shortened from: ".$url.")</small>";
	}
}elseif(stripos($_POST['url'],"url.php") or stripos($_POST['url'],"url.php")>=0){
	echo "You can't use a url that contains \\"url.php\\"";
}
?>

the table in the database:

CREATE TABLE short (
id int(11) NOT NULL auto_increment,
url text NOT NULL,
PRIMARY KEY (id)
);

7

Loads to go on there, thanks guys.

Thanks Bob for that script, it’s much appreciated.

8