How to re-direct URL?

Server Config
1

Hi guys, I would like a capability so that when someone visits these URLs,

http://www.domain.com/somedir/xyz.php
http://www.domain.com/somedir/info.php

they will be respectively re-directed to:

http://www.domain.com/somedir/main.php?p=xyz
http://www.domain.com/somedir/main.php?p=info

Any idea on how to do it in Apache or PHP ? Thanks.

2

What you’re looking for is Apache’s mod_rewrite. Here’s a great beginner’s article on URL rewriting from a pretty cool site, but here’s the basic gist:

You use regular expressions to parse the URL that the user requested, and tell the server which page it should actually send.

If you have mod_rewrite enabled on your server, you can just put the following in an .htaccess file located in your somedir folder:


RewriteEngine on
RewriteRule ^/?([a-z]+)\\.php$ main.php?p=$1
3

Thanks sdleihssirhc for your prompt reply. I’m a bit concerned with your regular expression though. I want only the files located under the “somedir” directory to be re-directed and not the files located outside of this directory. For example, when someone visits this link:

http://www.domain.com/somedir/info.php

it will be re-directed to: http://www.domain.com/somedir/main.php?p=info

But when he visits this site:

http://www.domain.com/somepage.php

it should not be re-directed.

Does your regex cover this case as well ?

Thanks a lot again.

4

Just make sure that you put your .htaccess file inside the somedir folder and you should be okay.

5

Ah, sdleihssirhc, your solution is “loopy.” You always must check the regex to see whether it’ll match the redirection, too, and, if it does, provide an exit strategy (with a better regex OR a RewriteCond).

Regards,

DK

6

Can you explain what about the rule puts it at risk for looping? I tried accessing main.php, thinking that maybe the regex doesn’t take parameters into account (so if you accessed main.php, it would try to load main.php?p=main, which would trigger with main.php again), but everything seemed to work fine.

7

sdleihssirhc,

Sure. Let me lead you through your code:

RewriteEngine on
RewriteRule ^/?([a-z]+)\\.php$ main.php?p=$1

RewriteEngine on is perfect.

The RewriteRule’s regex will match (Apache 1 or Apache 2 - good!) a lowercase letter filename with a php file extension. It will then redirect to main.php with a query string.

The problem is that main.php will be matched by {filename}\.php and redirected to main.php with a query string of p=main … until Apache 2 recognizes the loop or Apache 1 gets a restart.

Note 1: Because .htaccess is a per-directory resource, Apache will be looking for (and matching) filename.php then main.php then main.php then …

Note 2: This is very similar to the effect that (.*) has when redirecting to the same directory with the only difference being that you are aware enough to use good regex in your RewriteRule (although, these days, the /? isn’t necessary because there are very few Apache 1.x servers remaining).

You’ve done a good job (with the exception of the loop), though. My solution would be very similar:

RewriteEngine on
# Prevent the loop by requiring that there be no query string, i.e.
# RewriteCond %{QUERY_STRING} ^$
# OR that the file requested is not main.php (very slight preference)
RewriteCond %{REQUEST_URI} !main\\.php$
# I prefer my .htaccess to be in the DocumentRoot so I've got to include the somedir
RewriteRule ^somedir/([a-z]+)\\.php$ somedir/main.php?p+$1 [L]

I hope that answers your question (and provides a useable solution for tmyonline).

For tmyonline, may I offer the tutorial Article located in my signature – it’s helped members here for years.

Regards,

DK

8

Thanks guys, I feel good to have two experts, dklynn and sdleihssirhc, helping me.

Sure dklynn, where can I find it ? Thanks.

9

tmyonline,

Try clicking on the word “Article” in my signature.

Regards,

DK