How do I edit an external css file with PHP?

I have a page with an image. I want the client to be able to upload a new image into the database and then be able to switch out the image from within the CMS. Once they switch it in the CMS, I want PHP to edit the background image in the external css file.

Is it possible to do that? I know how to have PHP switch out an image tag in the HTML markup, but I would like to be able to 开发者_开发问答edit the external css file to keep my code cleaner.

If you're using Apache, you can also embed PHP code in your CSS files, by adding this to your apache conf:

AddHandler application/x-httpd-php .css

You can use the file access functions to permanently change it or, probably easier, make the CSS file itself a PHP script and put the logic in there for deciding how the CSS is to be created. Make sure to set the caching rules appropriately for the CSS file.

Adding to Ben and Sydius's answer which generates the dynamic CSS file.

How about having a seperate PHP driven CSS that supercedes the current one you have?

You can also manipulate it to avoid persistent cache of the older image by manipulating the CSS's URI.

 <link rel="stylesheet" href="path/to/sitelevel.css">
 <link rel="stylesheet" href="path/to/background-switcher.css.php?cache-buster123">