How do you redirect HTTPS to HTTP?

Question

This has not been tested but I think this should work using mod_rewrite

RewriteEngine On
RewriteCond %{HTTPS} on
RewriteRule (.*) http://%{HTTP_HOST}%{REQUEST_URI}

Keep in mind that the Rewrite engine only kicks in once the HTTP request has been received - which means you would still need a certificate, in order for the client to set up the connection to send the request over!

However if the backup machine will appear to have the same hostname (as far as the client is concerned), then there should be no reason you can't use the same certificate as the main production machine.

Based on ejunker's answer, this is the solution working for me, not on a single server but on a cloud enviroment

Options +FollowSymLinks
RewriteEngine On
RewriteCond %{ENV:HTTPS} on
RewriteRule (.*) http://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

For those that are using a .conf file.

<VirtualHost *:443>
    ServerName domain.com
    RewriteEngine On
    RewriteCond %{HTTPS} on
    RewriteRule (.*) http://%{HTTP_HOST}%{REQUEST_URI}

    SSLEngine on
    SSLCertificateFile /etc/apache2/ssl/domain.crt
    SSLCertificateKeyFile /etc/apache2/ssl/domain.key
    SSLCACertificateFile /etc/apache2/ssl/domain.crt

</VirtualHost>

If none of the above solutions work for you (they did not for me) here is what worked on my server:

RewriteCond %{HTTPS} =on
RewriteRule ^(.*)$ http://%{HTTP_HOST}/$1 [L,R=301]

all the above did not work when i used cloudflare, this one worked for me:

RewriteCond %{HTTP:X-Forwarded-Proto} =https
RewriteRule ^(.*)$ http://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

and this one definitely works without proxies in the way:

RewriteCond %{HTTPS} on
RewriteRule (.*) http://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

this works for me.

<VirtualHost *:443>
    ServerName www.example.com
    # ... SSL configuration goes here
    Redirect "https://www.example.com/" "http://www.example.com/"
</VirtualHost>

<VirtualHost *:80>
    ServerName www.example.com
    # ... 
</VirtualHost>

be sure to listen to both ports 80 and 443.