Apache Rewrite Mod

Question

I am trying to achieve virtual subdomain as my hosting provider has set a limitation on the number of subdomains I can have! I already have a wildcard DNS entry so all subdomains are accepted and send to the root of my domain. Here's what I have put in .htaccess to handle the redirection:

RewriteEngine on
RewriteCond %{HTTP_HOST} !^(www|admin).* [NC]
RewriteCond %{HTTP_HOST} ^([a-zA-Z0-9]+)\.domain\.-com
RewriteCond /home/username/public_html/subdomain/%1 -d
RewriteRule ^(.*) /home/username/public_html/subdomain/%1/$1

The problem is in the last line which does the actual redirection, the server shows a 500 (Internal server error), but the apache error log does not expand the error. In its place if I put something like:

RewriteRule ^(.*) index.php?path=/home/username/public_html/subdomain/%1/$1

It works fine... And the path is the correct file path.

Answer 1

I would advice to:

• first test if it's a subdomain (like you do) and if so make your tests on /subdomain/(realsubdomain)
• then if it's (www or admin) then refuse everything that tries to access to /subdomain/xxx

Note that I've removed (/home/username/public_html)

So this should be close to:

RewriteEngine on
# first handle subdomains
RewriteCond %{HTTP_HOST} !^(www|admin)\.* [NC]
RewriteCond %{HTTP_HOST} ^([a-zA-Z0-9]+)\.domain\.com
RewriteCond /home/username/public_html/subdomain/%1 -d
RewriteRule (.*) /subdomain/%1/$1
# then in main domains:
RewriteCond %{HTTP_HOST} ^(www|admin)\.* [NC]
# ...refuse access to subdomain:
RewriteRule ^/subdomain(.*) - [R=404,L]

NB: this is a 404 redirect, so you could make your own 404 at the very beginning of the rewriterules, something like:

ErrorDocument 404 /404.php
RewriteEngine on
RewriteRule /404.php - [QSA,L]
... blabla...

And in your 404.php handle the URL to display some nice message :)

Two hints:

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Please try to use the RewriteLog directive: it helps you to track down such problems:

# Trace:
# (!) file gets big quickly, remove in prod environments:
RewriteLog "/web/logs/mywebsite.rewrite.log"
RewriteLogLevel 9
RewriteEngine On

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My favorite tool to check for regexp:

http://www.quanetic.com/Regex (don't forget to choose ereg(POSIX) instead of preg(PCRE)!)