Executing PHP in CSS Files

In order to parse and execute PHP in a CSS file, all you have to do is tell Apache to treat CSS files as PHP, and just make sure you tell the browser that it’s NOT text/html (default mime type) but CSS.Very easy.

.htaccess File

Place a .htaccess file in the directory of the CSS file (if there isn’t one already). Simply add a directive to process the PHP in CSS files. Depending on your configuration, you might have to use a different directive. Here are the two most common ones I’ve been able to use:
Mod_PHP (Apache PHP Module)

#MOD PHP

	SetHandler application/x-httpd-php

Others:

#OTHERS
AddType application/x-httpd-php5 .css

(If you’re using php4, use x-httpd-php4)

CSS (and PHP) File

I recommend using this code just to test that your Apache directive is working. Hopefully this example shows the potential use for (server-side) executable code in CSS files.

<?php
	//make sure the browser treats this as CSS
	header("Content-Type: text/css");
 
	//browser detection
	if (strpos($_SERVER['HTTP_USER_AGENT'],"Internet Explorer") > 0) {
		$internet_explorer = true;
	}
 
	$baseColour = "#F3AA9C";
	$secondaryColour = "#CCAF1F";
	$foregroundColour = "#FFFFFF";
	$moduleWidth = "125px";
?>
 
#content {
	background:<?php echo $baseColour; ?>;
	colour:<?php echo $foregroundColour ?>;
}
 
#sideBar {
	background: <?php echo $secondaryColour; ?>;
	color:<?php echo $baseColour; ?>;
	width:<?php echo $moduleWidth; ?>;
}
 
#footer {
	color: <?php echo $secondaryColour; ?>;
	background:<?php echo $foregroundColour; ?>;
}

Obviously mixing PHP and CSS stuffs up syntax highlighting sorry.

Caveat

Most browsers will download the CSS file on every pageload – it’s not too difficult to implement cache-control, but I haven’t done it for this code.

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Warning: Unknown([PATH HERE]): failed to open stream: No such file or directory in Unknown on line 0

Some other Fatal error came up but I forgot to copy it, sorry.

The error message is unhelpful but it was pretty easy to fix. I just deleted the .htaccess file from the root and tested. It worked! After restoring a backup of the .htaccess file everything worked. Hooray!

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This can happen when you try doing a HTTP redirect or send HTTP 404, as it can happen whenever you try to send headers once they’ve already been sent. When a user sees this, they are basically left high and dry, often on a blank page. The solution is simple:

Detect if Headers Have Already Been Sent

Whenever you call header(); , call headers_sent(); first!

Example:

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4
5
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7

    if (!headers_sent()) {
        header('Location: ' . (!$absolute ? HOME_URL : "") . $page);
        die();
    } else {
        echo "\n\n<p>Couldn't redirect to " . htmlentities((!$absolute ? HOME_URL : "") . $page) . ", headers already sent.</p>\n\n";
        //do something here...
    }

Of course you should probably do thing useful

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Setting Up Apache’s “mod_rewrite” Modul

To implement these URLs with Apache, you will need to have the mod_rewrite module enabled. Here’s how to enable mod_rewrite:

1. Open the httpd.conf file from the …apache/conf/ directory
2. Uncomment the line “LoadModule rewrite_module modules/mod_rewrite.so” (by removing preceding #)

If you have more than one virtual server or directory set up, you might have to add something like this as well:

<Directory "PATHOFDIRECTORY">
    AllowOverride all
    Order allow,deny
    Allow from all
</Directory>

Next, you need to create a file named “.htaccess” at the website’s root directory (if you haven’t got one already)

In your .htaccess file, add the following rules:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

This will redirect all requests that don’t point to an existing file or directory to ‘index.php’.

You might (or might not) be thinking “How does that help implement clean URLs?” The next part will answer that question, but before proceeding – test your new Apache config and .htaccess file – restart Apache if necessary and try loading a directory that doesn’t exist (ie. http://yourwebsitehost/page/5/your-information/). If it loads your index.php page – we’re ready to continue.

Getting PHP to Interpret The URLs

Ok, the hard part is done. Now I’ll explain what we want when a user requests a page:

1. User requests “/page/5/your-information/”
2. Apache redirects the request to “index.php” without changing the user’s URL
3. index.php breaks up the requet URI and loads page.php instructing it to load page ’5′

This might seem a bit difficult (or, if you’re experienced, very easy) – it honestly is rather easy. Once you understand how it works, you might decide to do it differently, but here is a really simple example of a website that contains information ‘pages’ and information about the ‘authors’ of those pages.

In our example, we have three php files:

• index.php
• page.php
• author.php

“index.php”

<?php
//$urlVariables is an array that contains the different bits of information in the request.
$urlVariables = explode("/",$_SERVER['REQUEST_URI']);
//If the user requested '/page/6/about-elephans/' then $urlVariables[1] would be 'page', $urlVariables[2] would be '6' and so on.

if ($urlVariables[1] == "page") {
//the user is requesting an information page
    include "page.php";
} elseif $urlVariables[2] == "author" {
    //the user is requesting author information
    include "author.php";
} else {
    //load the home page
    include "default.php";
}?>

“page.php”

<?php//load an object that deals with pages (to keep the tutorial simple)
include "classes/page.php";
$page = new page;
//$urlVariables will contain the page id as the 2nd array element (ie. /page/pageid/page-name-here/)$page_id = $urlVariables[2];
//the page name part of the URL is ignored when loading because we only use ID to load pages - it's just good for search engines and people.

//get the page class to load the page
if ($page->load_page($page_id)) {?>

<h1><?php echo $page->page_name(); ?></h1>
<p><?php echo $page->page_content(); ?></p>
<p>Written by <a href="<?php echo $page->author_url(); ?>"> <?php echo $page->author_name(); ?> </a></p><?php

} else {

    //error!
    include "error.php";
}>

“about.php”

<?php

//load an object that deals with authors (again, to keep the tutorial simple)
include "classes/author.php";
$author = new author;
//$urlVariables will contain the page id as the 2nd array element (ie. /author/authorid/author-name-here/)
$author_id = $urlVariables[2];
//again, the author name part of the URL is ignored when loading because we also only use ID to load authors - it is just good for search engines and people.

//get the author class to load the page
if ($author->load_author($author_id)) {?>
<h1><?php echo $author->author_name(); ?></h1>
<h2>Bio</h2><p><?php echo $author->author_information(); ?></p>
<h2>All pages by <?php echo $author->author_name; ?></h2>
<$php echo $author->page_list; 

} else {
    //error!
    include "error.php";
}
?>

Now that example was probably a bit excessive. Here’s a basic overview of how it works:

1. The index.php page is loaded, and ‘explodes’ the request part of the URL into an array ($urlVariables in the example)
2. You then interpret the array elements to decide what to show to the user. ($urlVariables[1] determined whether to show a page or an author profile and $urlVariables[2] was an ID for either the page or the author in our example)

It’s that simple. This method is SUPER flexible if you build a strong framework around it.

Good luck!

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So in my case, the function is fed a YouTube URL and returns the video id variable (v) – So an example:
Input: http://au.youtube.com/watch?v=le860Jd-FqI&feature=related
Output:
$output['v'] = “le860Jd-FqI”
$output['feature'] = “related”

And so witout further ado, here’s the actual code:

function getVariableFromUrl($url) {		//we need to see if this URL is passing any GET variables

 	$variablesStart = strpos($url, "?") + 1;

if (!$variablesStart) {

 		// no variables!

 		return(false);

 	}

//before we extract the variables, we need to remove any anchors

$variablesEnd = strpos($url,"#",$variablesStart);

if ($variablesEnd) {

 		$getVariables = substr($url, $variablesStart, $variablesEnd - $variablesStart);

 	} else {

 		$getVariables = substr($url, $variablesStart);

 	}

//next, we split the URL into an arrays containing variable name and value pairs (ie. "variable=value")

 	$variableArray = explode("&", $getVariables);

//we will iterate through each of the array pairs (ie. "variable=value")

 	foreach ($variableArray as $arraySet) {

$nameAndValue = explode("=", $arraySet);

//using the above examples, $nameAndValue[0] would be "variable" and $nameAndValue[1] would be "value"

 		$output[$nameAndValue[0]] = $nameAndValue[1];

}

return($output);

}

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