Question

How would I rewrite all requests to maintenance.php, if it exists, except images, and except an IP white list.

If maintenance.php does not exist it should rewrite to a bootstrap (index.php) if the requested file does not exist.

If maintenance.php does exist and the IP is in the white list, then it should rewrite to a bootstrap (index.php) if the requested file does not exist.

I have tried many variations of the following:

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /

    RewriteCond %{DOCUMENT_ROOT}/maintenance.php -f
    RewriteCond %{REQUEST_FILENAME} !\.(jpg|png|gif)$
    RewriteCond %{REMOTE_ADDR} !^123\.123\.123\.123$
    RewriteCond %{REMOTE_ADDR} !^111\.111\.111\.111$
    RewriteRule . maintenance.php [L]

    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule . index.php
</IfModule>

Answer 1

I would do it in reverse. Rewrite to the bootstrap if the maintenance page doesn’t exist or the IP is valid.

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{DOCUMENT_ROOT}/maintenance.php !-f [OR]
RewriteCond %{REMOTE_ADDR} ^123\.123\.123\.123$ [OR]
RewriteCond %{REMOTE_ADDR} ^111\.111\.111\.111$
RewriteRule . index.php [L]

RewriteCond %{DOCUMENT_ROOT}/maintenance.php -f
RewriteCond %{REQUEST_FILENAME} !\.(jpg|png|gif)$
RewriteCond %{REMOTE_ADDR} !^123\.123\.123\.123$ [OR]
RewriteCond %{REMOTE_ADDR} !^111\.111\.111\.111$
RewriteRule . maintenance.php [L]

So, basically it will run index.php IF:

(Not a file) 
&& (Not a dir) 
&& (
    (Maintenance Doesn't Exist) 
    || (Remote Addr == 123.123.123.123)
    || (Remote Addr == 111.111.111)
)

We could expand this out using propositional logic, but why bother…