bla.st : process your urls in php with apache mod

Every cool web 2.0 application these days features nice URLs, where instead of long complicated query strings eg:
http://bla.st/?section=design&page=1
we have a nice, simple folder structure:
http://bla.st/design/1/

We use Apache's mod_rewrite to accomplish this. mod_rewrite is very powerful, but can be tricky to debug. For our bla.st project, we decided to put all URLs through a single PHP script, and process them there. The advantage is then we can do what ever we want with the URLs.

Let's go over the URLs that we wanted working for bla.st. First of all we wanted to divide bla.st up by country using sub domains eg. http://nz.bla.st/ for the New Zealand site, http://us.bla.st/ for the US site. Our first step was to set the DNS A records for bla.st and *.bla.st to our server IP address. The * is a wildcard, so anything.bla.st (including www.bla.st) will take you to our server.

In our Apache httpd.conf file we set the ServerName and ServerAlias for our bla.st virtual host as follows:

ServerName bla.st ServerAlias *.bla.st

This means that http://anything.could.go.here.bla.st/index.php would go to the file index.php

The next step is to set a rewrite rule that puts any URL through a single controller file, in this case we choose index.php. Here's our completed virtual host entry, with the reason for each line in a comment under the line.

<VirtualHost [OUR IP]> RewriteEngine on RewriteRule ^/.*(\.css)|(\.php)|(\.jpg)|(\.png)|(\.html)|(\.gif)|(\.js)|(\.txt)|(\.ico)$ - [L] # [L] stops mod_rewrite processing so any URLs ending with those filetypes will be treated like normal. RewriteRule ^/static/(.*) - [L] # stops mod_rewrite processing the URL for anything in the folder 'static' RewriteRule ^/([a-zA-Z0-9_/+.!*',()~-]+)$ /index.php [QSA] # pass any request for a folder to index.php. [QSA] ensures any query string is passed on ServerName bla.st ServerAlias *.bla.st </VirtualHost>

The result is any request for the following style URLs, will go through index.php:
http://nz.bla.st/my/folder/
http://nz.bla.st/web-2.0/
http://bla.st/login/
http://www.bla.st/design/2/?view=big

In index.php we have code that splits the URL and directory into arrays:

<?php // get the server variable that contains the directory structure eg. /design/2/, and make sure it's lowercase. $string = strtolower($_SERVER['SCRIPT_NAME']); // make sure there are no funny characters our app doesn't allow $string = ereg_replace("[^a-z0-9_/+.!*',()~-]", "", $string); // explode the URL around the / $uri_array=explode('/', $string); // make sure a request for /index.php is treated the same as a request for / if ($uri[1]=="index.php") $uri[1]=""; // explode the HTTP_HOST around the . so www.bla.st will become an array of www, bla and st $host_array=explode('.', strtolower($_SERVER['HTTP_HOST'])); // if the first item is 2 characters, treat it as a country code, otherwise if (strlen($_HOST[0])==2) { $country_code=$_HOST[0]; } // continue with our app ?>

Now we have the URL split up nicely, we can include files as needed depending on the URLs requested. There is a slight overhead having to go through the index file, but the flexibility might be worthwhile for your project.

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Process your URLs in PHP with Apache mod_rewrite and wildcard DNS