why http redirect to https code example

Example 1: how to redirect http to https

//PUT THIS IN .htaccess

RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^gymstatistics\.altervista\.org [NC,OR]
RewriteCond %{HTTP:CF-Visitor} '"scheme":"http"'
RewriteRule ^ https://gymstatistics.altervista.org%{REQUEST_URI} [NE,R=301,L]

Example 2: redirect http non www to https www

RewriteEngine On

RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301]

RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://www.example.com/$1 [L,R=301]

# If this does not work:
RewriteEngine On

RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301]

RewriteCond %{SERVER_PORT} !^443$
RewriteRule ^(.*)$ https://www.example.com/$1 [L,R=301]