htaccess - redirect to https not working - apache

Question

Per: https://exp-resso.com/blog/post/2011/08/securing-your-expressionengine-website-with-https
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteCond $1 ^(member|account|checkout|system) [NC]
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
This tells your server “If HTTPS is off, and the request starts with
member OR account OR checkout OR system (not case sensitive), redirect
to https://current-domain/current-page”. It’s a nice simple method of
locking down entire subfolders / template groups.
I've added this to my htaccess file like this:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteCond $1 ^(sign-in|sign-up) [NC]
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
</IfModule>
However, when I go to my http://mydomain.com/sign-in, the URL doesn't change to https://mydomain.com/sign-in. Any idea what's wrong?
EDIT 1:
My htaccess also has the following (to remove "www") and I wonder if having both might be causing the problem?
RewriteCond %{HTTPS} !=on
RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
RewriteRule ^ http://%1%{REQUEST_URI} [R=301,L]
EDIT 2:
Process of elimination, it turns out this is causing the problem:
<IfModule mod_rewrite.c>
RewriteEngine On
# Removes index.php from ExpressionEngine URLs
RewriteCond $1 !\.(gif|jpe?g|png)$ [NC]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php/$1 [L]
</IfModule>
When I comment out the RewriteRule, the https:// is forces. What's causing the conflict?

Answer 1

Try to put (sign-in|sign-up) condition inside RewriteRule:
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^(sign-in|sign-up)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,NC,R=301]

Answer 2

What about this? (If port == 80 then redirect )
RewriteEngine on
RewriteCond %{SERVER_PORT} 80
RewriteCond %{REQUEST_URI} member [OR]
RewriteCond %{REQUEST_URI} account [OR]
RewriteCond %{REQUEST_URI} checkout [OR]
RewriteCond %{REQUEST_URI} system
RewriteRule ^(.*)$ https://%{SERVER_NAME}%{REQUEST_URI} [R=301,L]

Answer 3

First make sure that rewrite works on your server and that the htaccess is read (e.g. by issuing a redirect on every URL).
Then use RewriteCond %{REQUEST_URI} ^/(sign-in|sign-up) instead of RewriteCond $1 ^(sign-in|sign-up) [NC]
It works and is easier to read too
So you htaccess should look like this
RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteCond %{REQUEST_URI} ^/(sign-in|sign-up) [NC]
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]