How to rewrite a request to different files based on the domain name in ".htaccess"?

Question

I run the website https://www.1.example. The contents of my .htaccess file are as follows:

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ \city.php?q=$1 [QSA,L]

I would like to connect the second domain https://2.example to this site. How to modify the .htaccess file so that it redirects the query to the appropriate file due the domain used by the visitor. My point is that when someone enters my website from the domain https://1.example or https://www.1.example, he should be redirected to the file city.php?q= and when he enters from the domain https://2.example or https://www.2.example to the file file2.php?q=.

Answer 1

You've not stated how you are currently handling requests for the root directory (homepage), as this is not handled by the directives you have posted (since the second condition explicitly excludes all directories). However, I'll assume that all requests for the first domain are being handled correctly by the existing rule (and server config) and any requests for the second domain (including the root directory) should be sent to file2.php.

A couple of asides...

RewriteRule ^(.*)$ \city.php?q=$1 [QSA,L]

The backslash-escape at the start of the substitution string looks like an error/typo. There is no need to escape a literal c here. You probably meant to use a (forward) slash (ie. /), but this is not required either (and best omitted).

Minor point, but the start-of-string (^) and end-of-string ($) anchors on the RewriteRule pattern ^(.*)$ are not required since regex is greedy by default.

RewriteCond %{REQUEST_FILENAME} !-d

Do you need to make an exception for requests that map to physical directories? Do you need to be able to access directories themselves? Although you see this a lot, it's actually very rare that this would be required. Without this, your rules can be simpler and more efficient.

The presence of this condition will often mean that a request for a directory would result in a "403 Forbidden". Whereas, without this condition the request would be routed through your front-controller, which would probably result in a "404 Not Found" (which is often preferable).

Solution

Try the following:

RewriteEngine on

# (Optional) Abort early if either front-controller already reached
RewriteRule ^(city|file2)\.php$ - [L]

# If the request matches the first domain then skip the next 2 rules
RewriteCond %{HTTP_HOST} ^(www\.)?1\.example [NC]
RewriteRule ^ - [S=2]

# Second domain
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule (.+) file2.php?q=$1 [QSA,L]

# Second domain root directory (homepage)
RewriteRule ^$ file2.php [L]

# First domain
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule (.+) city.php?q=$1 [QSA,L]

Note that I also changed the RewriteRule pattern from .* to .+ which avoids an unnecessary filesystem check for requests to the document root.

There is also an additional question to ponder... what do you want to happen if the front-controller (ie. city.php or file2.php) is requested directly? Allow it? Block it? Redirect it?