Help needed with writing a header image rotation script

[princesspepper]

I want to include a small script to rotate the image in the header so that it displays an alternative image on certain special days which I can specify. A bit like Google does.

I am running VB4.2 PL2

Here is the script, which is kept in a file called 'headerrotate.php' in my plugins/headerrotate/ folder :

PHP Code:

<?php


// example random image based on time


// fetch date unit that we will be using. d:m will give the day and month in numeric form with leading 0

// You can find other date units aside from 'd:m' on [url]http://www.php.net/date[/url]

// You could also combine these, for example 'H:i" will give you hours:minutes


$HeaderDateUnit = date('d:m');



// the switch statement compares the variable $HeaderDateUnit to every "case"

//    if it matches, whatever command after the colon is performed.

//    the break; statement tells the switch statement to stop attempting comparisons

//    Before we break;, we assign an image filename to $image variable.

//    The default : is what happens if the switch statement doesn't match anything to $HeaderDateUnit.


switch($HeaderDateUnit)

{
// New Year
    case "01:01" : $image = "images/misc/headers/newyear.png";
    break;

// King's Day
    case "06:01" : $image = "images/misc/headers/kingsday.png";
    break;

// Valentine's Day
    case "14:02" : $image = "images/misc/headers/valentines.png";
    break;

// Default image
    default : $image = "images/misc/vbulletin4-logo.png";
    break;

}


// "echo" prints the variable $image onto the screen (in this case, our filename).

echo $image;


?>

I have read the manual here : http://www.vbulletin.com/docs/html/m..._externalfiles

And it says I first need to create a plugin, which I have done... however when I make the plugin active (all image files that are referenced are uploaded, as is the php file) all that happens is a blank page, so I am assuming that something is wrong because what 'should' happen is that it returns the image variable, and as this is not used at present until I change the header template to include it in the code, it would do nothing...

This is my plugin code :

Hook Location : global_start
Execution Order : 5
Plugin PHP Code :

PHP Code:

ob_start();
  include('plugins/headerrotate/headerrotate.php');
  $headerrotate = ob_get_contents();
  ob_end_clean(); 


Also, I understand from the tutorial that I will need to change the {vb:stylevar titleimage} to {vb:raw headerrotate} in the header template. Is this correct?

Finally, it also mentions in the tutorial that in vBulletin 4+, you need to register variables for them to be available in specific templates and usable. You would do this with code like this:

vB_Template:reRegister('FORUMHOME',array('includ edphp ' => $includedphp));

What does this mean, and where would I do this? Is this why I'm getting my blank page?

Any help would be greatly appreciated