http:// redirects to https://www.www with htaccess - apache

Question

I have a CI installation in my root domain. SSL certificate is installed and working properly. When I redirect http:// to https://www it redirects to https://www.www (an extra www), that too on some computers and some browsers as users have reported. However, when I remove 'www' from redirection, its all fine. Seems like www is looping. So far, I've digged my code hundred times, and see no sign of redirection from code (I mean addition of extra www). I'm doing it with htaceess. Any help will be highly appreciated. This is my htaccess:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
#Force SSL
RewriteCond %{HTTPS} !on
RewriteRule ^(.*)$ https://www.%{HTTP_HOST}%{REQUEST_URI} [R,L]
#Removes access to the system folder by users.
#Additionally this will allow you to create a System.php controller,
#previously this would not have been possible.
#'system' can be replaced if you have renamed your system folder.
RewriteCond %{REQUEST_URI} ^system.*
RewriteRule ^(.*)$ /index.php/$1 [L]
#Checks to see if the user is attempting to access a valid file,
#such as an image or css document, if this isn't true it sends the
#request to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php/$1 [L]
</IfModule>
I'm running it on apache with Centos VPS.
Thank you so much!

Answer 1

The HTTP_HOST is the "target host" part of the request, like: www.mydomain.com.
The REQUEST_URI is generally the path which was given in order to access a certain page; for instance, ‘/folder/index.html’.
In your RewriteRule you say to put 'www.' in front of the requested domainname.
You don't want that, when someone asks for http://www.yourdomain.com.
Without the www. in your RewriteRule someone who requests for http://yourdomain.com gets redirected to https://yourdomain.com
When you want to redirect to https and www you need to add conditions. Look into Apache docs on Canonical host and on questions/4083221/how-to-redirect-all-http-requests-to-https for this solution:
RewriteCond %{HTTPS} !=on [OR]
RewriteCond %{HTTPS_HOST} !^www.yourdomain.com$ [NC]
RewriteRule ^(.*)$ https://www.yourdomain.com/$1 [L,R=301]