PHP Simple Splitter - Even Rotation

[Mike]

If you do any sort of landing page testing, you know the value of a good splitter. Here is mine. With it you can get even rotation regardless of the number of pages you want to split. Just change a couple of items, and have at it.

If you want to rotate a lot of things, then you're better off re-writing this to use an array and loop it.

But for 2 - 4 pages, this is pretty idiot proof.


For an A / B split:

            $file = 'count.txt';  // file where the number is stored
            $num = file_get_contents($file); // variable to store number from file
            
            
                if ($num == 1) {
                        header( 'Location: http://website1.com/lp1.php?'.$_SERVER['QUERY_STRING'] ) ;
                        $num++;    // increment number by one    

                } else {
                        $num = $num-1; // decrease number by number of tests minus 1. Ex: 3 tests = decrease by 2
            
                }
            
            
            file_put_contents($file, $num); // write new number to file

For A / B / C split

            $file = 'count.txt';  // file where the number is stored
            $num = file_get_contents($file); // variable to store number from file
            
            
                if ($num == 1) {
                        header( 'Location: http://website1.com/lp1.php?'.$_SERVER['QUERY_STRING'] ) ;
                        $num++;    // increment number by one    
                } elseif ($num == 2) {
                        header( 'Location: http://website1.com/lp2.php?'.$_SERVER['QUERY_STRING'] ) ;
                        $num++;    // increment number by one    
                } else {
                        $num = $num-2; // decrease number by number of tests minus 1. Ex: 3 tests = decrease by 2
            
                }
            
            
            file_put_contents($file, $num); // write new number to file

You may notice that the else statement in these examples only decreases the count and doesn't redirect. That is because I usually put this on one of the pages I am testing (above the HTML). If you want to put this script on a splitter page (ie. split.php), then simply add a redirect to the else statement, like this:

          $file = 'count.txt';  // file where the number is stored
            $num = file_get_contents($file); // variable to store number from file
            
            
                if ($num == 1) {
                        header( 'Location: http://website1.com/lp1.php?'.$_SERVER['QUERY_STRING'] ) ;
                        $num++;    // increment number by one    
                } elseif ($num == 2) {
                        header( 'Location: http://website1.com/lp2.php?'.$_SERVER['QUERY_STRING'] ) ;
                        $num++;    // increment number by one    
                } else {
                        header( 'Location: http://website1.com/lp3.php?'.$_SERVER['QUERY_STRING'] ) ;
                        $num = $num-2; // decrease number by number of tests minus 1. Ex: 3 tests = decrease by 2
            
                }
            
            
            file_put_contents($file, $num); // write new number to file

Also, since the php header redirect is not relative, you can also test between domains.

Enjoy!

 

[mattseh]

This is not atomic, if that matters, consider using redis's incr command and then get the modulus of how many items you have.

Or do what I do, and pick a random link each time. Over a decent number of clicks, it's close enough to even.

PHP for the redis thing:

$urls = array('a', 'b', 'c');
$url = $urls[$redis->incr('counter') / count($urls)];

Didn't test, haven't written PHP in about 2 years, good luck.

Edit: Mike, even with your files solution, why not just increment and take the modulus? It keeps the code simpler. In your posted code, you only ever direct to n-1 urls, where n is the number you actually want.

 

[Jake232]

As above, writing a file like this isn't going to work. It could be edited inbetween as mattseh said because it's not atomic.

 

[gutterseo]

Just incase anyone wants the simple version:

<?
// Read from file/db whatever.
$urls = ['http://gayseks.com', 'http://wealllose.co.uk'];
$len = count($urls);
// Redirect here if wanted.
echo $urls[mt_rand(0, $len) % $len];
?>

 

[Mike]

Thanks for the feedback guys!

Why didn't I do it a different way? Simple: I'm a marketer first, and coder-wannabe second. So, I code in what is easiest for me, knowing there are smarter coders here that are more than happy to pick apart my chicken scratch and improve upon it.

Seriously though, I appreciate the help. Love learning better ways to do things.