How to redirect www to non-www https?

Question

I have installed https on my domain. And all this cases are available of my website:

http://example.com        // will be redirected to https://example.com
https://example.com
http://www.example.com    // will be redirected to https://www.example.com
https://www.example.com

See? everything will be using https protocol. All fine.

---

Now I need to redirect all www to non-www . So http://www.example.com and https://www.example.com should be redirected to https://example.com (in other word, all cases should be redirected to this) .

Here is my current code in the /etc/apache2/sites-avalible/000-default.conf :

<VirtualHost *:80>
.
.
.
RewriteEngine on
RewriteCond %{SERVER_NAME} =lamtakam.com [OR]
RewriteCond %{SERVER_NAME} =www.lamtakam.com
RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]

RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC]               -- this
RewriteRule ^(.*)$ https://%1/$1 [R=301,L]              -- and this are for www redirection
                                                        -- but doesn't work
</VirtualHost>

any idea?

also lamtakam is my exact domain I was talking about, if you need to check something.

---

Edit:

Currently I have this inside .htaccess file on the root of my project:

RewriteEngine on

Options -Indexes

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d

# this doesn't work on some version of xampp
# RewriteRule ^(.*)$ index.php?rt=$1 [L,QSA]

RewriteRule ^([\s\S]*)$ index.php?rt=$1 [L,B,QSA]

ErrorDocument 404 /error404.html

Answer 1

If you want rules in VirtualHost then it would be 2 set of rules. If you can keep rules in site root .htaccess then it would be a single rule. I am providing .htaccess rule here:

RewriteEngine On

RewriteCond %{HTTP_HOST} ^www\. [NC,OR]
RewriteCond %{HTTPS} !on
RewriteCond %{HTTP_HOST} ^(?:www\.)?(.+)$ [NC]
RewriteRule ^ https://%1%{REQUEST_URI} [R=301,L,NE]

Make sure you remove your existing rules shown in VirtualHost above and you test in a new browser to avoid old browser cache.