.htaccess redirect code - .htaccess

Question

I currently use the following code for my htaccess file. It redirects to https://www.example.com
#if not forum.example.com and not ssl then redirect
RewriteCond %{HTTP_HOST} !^forum\.
RewriteCond %{SERVER_PORT} !443
RewriteRule ^(.*)$ https://www.%{HTTP_HOST}/$1 [R,L]
#redirect if https://forum.example.com
RewriteCond %{HTTP_HOST} ^forum\.
RewriteCond %{SERVER_PORT} 443
RewriteRule ^(.*)$ http://forum.%{HTTP_HOST}/$1 [R,L]
The problem I have is when I go to
http://www.example.com
, this code makes it redirect to
https://www.www.example.com
instead of
https://www.example.com.
Anyone know how I can fix this?
If you require additional information to assist, just let me know.

Answer 1

The first rewrite rule is executed if 2 negative conditions are met: Not forum and not SSL, but the rewrite inserts www always, even when it is already in the URL. It is not previously checked.
I think the best way to correct the problem without modifying the actual rules, except removing the www from the first substitution, is by adding another rule at the begining, like this:
#non-www to www
RewriteEngine On
RewriteCond %{HTTP_HOST} ^example\.com/?$
RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301]
#if not forum.example.com and not ssl then redirect
RewriteCond %{HTTP_HOST} !^forum\.
RewriteCond %{SERVER_PORT} !443
RewriteRule ^(.*)$ https://%{HTTP_HOST}/$1 [R,L]
#redirect if https://forum.example.com
RewriteCond %{HTTP_HOST} ^forum\.
RewriteCond %{SERVER_PORT} 443
RewriteRule ^(.*)$ http://forum.%{HTTP_HOST}/$1 [R,L]
What the added rule does, is to rewrite any URL without www to one with www. The resulting URL is then presented to the other rules.
I don't know if these 2 last rules work as intended, I guess they do. I am just trying to solve the www duplication issue in the question.
Hope this helps.