htaccess rewrite rule all existing files and directories in one domain go to same filepath in another domain - apache

Question

I'm trying to write an htaccess rewrite rule to send all existing files and directories at the domain http:// or https:// and www or not lun.re to lunre.com.
So lun.re/admin, which does exist would go to lunre.com, but lun.re/new, which doesn't exist would stay at lun.re, but would redirect to https://lun.re/new.
Here's what I have so far:
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteCond %{HTTP_HOST} ^lun\.re$ [OR]
RewriteCond %{HTTP_HOST} ^www\.lun\.re$
RewriteCond %{REQUEST_URI} !^/$
RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/\.well-known/acme-challenge/[0-9a-zA-Z_-]+$
RewriteCond %{REQUEST_URI} !^/\.well-known/pki-validation/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
RewriteRule ^(.*)$ https://lunre.com/ [R=301,L]
RewriteCond %{HTTPS} off
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [NE,L,R]
Lines 5-8 were already there from my hosting provider.
I've also tried this:
RewriteCond %{REQUEST_FILENAME} !-d [OR]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ /loader.php [L,R]
RewriteCond %{REQUEST_FILENAME} -d [OR]
RewriteCond %{REQUEST_FILENAME} -f
RewriteCond %{HTTP_HOST} ^(www\.)?lun.re$
RewriteRule ^ http://lunre.com/ [L,R]
But then I get a too many redirects error.
What exactly I am trying to do is if it does exist and the domain is lun.re then go to https://lunre.com/file-or-dir (the same filepath at the long url) otherwise if it doesn't exist then stay at the current domain and go to https://currentdomain/loader.php

Answer 1

You can use this:
RewriteEngine on
# http to https
RewriteCond %{HTTPS} off
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [NE,L,R]
#redirect all existing files/directories to http://lunre.com
RewriteCond %{REQUEST_FILENAME} -d [OR]
RewriteCond %{REQUEST_FILENAME} -f
RewriteCond %{HTTP_HOST} ^(www\.)?lun.re$
RewriteRule ^ http://lunre.com/ [L,R]
You don't need a RewriteRule to Redirect non-existent requests back to your main domain as the Rule only redirects existing files/folders.