Codeigniter and .htaccess dynamic sub domain creation using URL rewrite

For a project I was trying to make dynamic sub domains for every user. I knew that it can be done by .htaccess mod_rewrite. But I didn’t know exactly how. Then I googled for solution and got a large number of tutorials. There I got some working tutorials too.

But the problem was, using those tutorials I can easily point a file like this:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC]
RewriteRule ^(.*)$ http://%1/$1 [R=301,L]

RewriteCond %{HTTP_HOST}  ^([^.]+)\.example\.com$
RewriteCond %{HTTP_HOST} ^([^.]+)\.example\.com$
RewriteRule ^(.*)$ user.php?uid=%1 [L]

And also like this:

<IfModule mod_rewrite.c>
   Options +FollowSymLinks
   Options +Indexes
   RewriteEngine On
   RewriteBase /
   RewriteCond %{HTTP_HOST} !www.example.com$ [NC]
   RewriteCond %{REQUEST_URI} ^/$
   RewriteCond %{HTTP_HOST} ^(www.)?([a-z0-9-_]+).example.com [NC]
   RewriteRule (.*) /welcome/user/%2 [R]
</IfModule>

But these don’t work for Codeigniter. Second one work but change the browser URL. So this is a big problem. I tried removing [R]. But then no redirection.

Then I start reading mod_rewrite documentation. And finally realize that it is happening for a flag. You have to set flag [P]. It treat the URL as a proxy. So your URL in browser will not change. I am writing this article because when i searched there were not enough documentation to describe this problem simply.

Hope this will help you.

Final and Working Code:

<IfModule mod_rewrite.c>
   Options +FollowSymLinks
   Options +Indexes
   RewriteEngine On
   RewriteBase /

   RewriteCond %{HTTP_HOST} !www.example.com$ [NC]
   RewriteCond %{REQUEST_URI} ^/$
   RewriteCond %{HTTP_HOST} ^(www.)?([a-z0-9-_]+).example.com [NC]
   RewriteRule (.*) /index.php/controller/function/%2 [P]

   RewriteCond $1 !^(index\.php|images|robots\.txt|css|js)
   RewriteRule ^(.*)$ /index.php/$1 [L]
</IfModule>