etherpad.ssl.conf

<VirtualHost *:443>
    ServerName ETHERPAD_WEB_ADDRESS

    # SSL configuration
    SSLEngine on
    # If you hold wildcard certificates for your domain the next two lines are not necessary.
    SSLCertificateFile "/etc/letsencrypt/live/ETHERPAD_WEB_ADDRESS/cert.pem"
    SSLCertificateKeyFile "/etc/letsencrypt/live/ETHERPAD_WEB_ADDRESS/privkey.pem"
    
    ProxyVia On
    ProxyRequests Off
    ProxyPreserveHost on    

    <Location />
        ProxyPass http://localhost:ETHERPAD_PORT/ retry=0 timeout=30
        ProxyPassReverse http://localhost:ETHERPAD_PORT/
    </Location>
    <Location /socket.io>
        # This is needed to handle the websocket transport through the proxy, since
        # etherpad does not use a specific sub-folder, such as /ws/ to handle this kind of traffic.
        # Taken from https://github.com/ether/etherpad-lite/issues/2318#issuecomment-63548542
        # Thanks to beaugunderson for the semantics
        RewriteEngine On
        RewriteCond %{QUERY_STRING} transport=websocket    [NC]
        RewriteRule /(.*) ws://localhost:ETHERPAD_PORT/socket.io/$1 [P,L]
        ProxyPass http://localhost:ETHERPAD_PORT/socket.io retry=0 timeout=30
        ProxyPassReverse http://localhost:ETHERPAD_PORT/socket.io
    </Location>
    
    <Proxy *>
        Options FollowSymLinks MultiViews
        AllowOverride All
        Order allow,deny
        allow from all
    </Proxy>
</VirtualHost>