A classic sysadmin scenario is to configure new Apache webserver with requirement to have an SSL ceriticate installed and working on port 443 and all requests coming on port 80 to be redirected to https://.
On Apache this is done with simple mod_rewrite rule:
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}
Before applying the rule don't forget to have Apache mod_rewrite enabled usually it is not enabled on default most Linux distributions by default.
On shared hostings if you don't have access to directly modify Apache configuration but have .htaccess enabled you can add above rules also to .htaccess
Add this to respective VirtualHost configuration and restart Apache and that's it. If after configuring it for some reason it is not working debug mod_rewrite issues by enabling mod_rewrite's rewrite.log
Other useful Apache mod_rewrite redirect rule is redirect a single landing page from HTTP to HTTP
RewriteEngine On
RewriteRule ^apache-redirect-http-to-https.html$ https://www.site-url.com/apache-redirect-http-to-https.html [R=301,L]
!Note! that in case where performance is a key requirement for a website it might be better to use the standard way to redirect HTTP to HTTPS protocol in Apache through:
To learn more on mod_rewrite redirecting check out this official documentation on Apache's official site.
