To cut a long story short. I needed to get Roundcube webmail to work over a secure reverse proxy. I wrote a patch because it dosen't work out of the box.

1. Grab one of the matching patches

   • round­cube­mail-0.5
   • round­cube­mail-0.6
   • round­cube­mail-0.7

2. Apply the patch

   cd project && patch -p0 < file.patch
   

3. Paste the following lines into your main config file

   // enable requests over a reverse proxy
   // eg: https://rproxy_host.rproxy_path.$_SERVER['REQUEST_URI']
   $rcmail_config['rproxy_host'] = null; // eg. 'ssl-account.com'
   $rcmail_config['rproxy_path'] = null; // eg. 'app.my-domain.com'
   

Sug­ges­tions are welcome.