htaccess redirect without user knowing - php

Question

We are running multiple domains through the same code and we want to save their images in their respective folders. Here's what we are doing.
/images/www.domain1.com/logo.jpg
/images/www.domain2.com/logo.jpg
now, what I want to know is, is this possible in htaccess that we rewrite the urls without user suspecting anything. This is what I want that
<img src="/images/logo.jpg" />
should internally become through htaccess
RewriteRule ^images/(.*)$ /images/{HTTP_HOST}/$1 [L,R=301]
But my question is,
The above redirect continually loops
Can I achieve the img effect without user or admin suspecting anything?
Sincerely,
Khuram

Answer 1

Remove the R=301 to simply do a rewrite rather than a redirect:
RewriteRule ^images/(.*)$ /images/{HTTP_HOST}/$1 [L]
The reason it's continually looping is that the 301 redirect causes a new request to be created for the url images/www.domain1.com/logo.jpg. That URL also matches your ^images/(.*)$ rule, so it is redirected again, ad infinitum.
If you really want to do a 301 redirect (I suspect you don't, but if you did), you could solve the infinite looping problem by adding some rewrite conditions to skip the redirect if the domain is already included:
RewriteCond {REQUEST_URI} !^images/www.domain1.com/(.*)$
RewriteCond {REQUEST_URI} !^images/www.domain2.com/(.*)$
RewriteRule ^images/(.*)$ /images/{HTTP_HOST}/$1 [L,R=301]

Answer 2

You definitely should not use R flag if you don't want to change URL in browser. However even without R flag your RewriteRule will loop infinitely and you will eventually get internal server error. Use RewriteRule like this:
RewriteCond %{ENV:REDIRECT_STATUS} !200
RewriteRule ^images/(.*)$ images/%{HTTP_HOST}/$1 [L,NC]
Which is using a special internal variable called {ENV:REDIRECT_STATUS} that is set to 200 once RewriteRule rule is applied successfully.