I would like to access the search engine via https://. Does Alkaline support SSL? Can the Apache proxy mechanism be configured to filter requests and forward them to Alkaline?

Alkaline does not have a native support for SSL. You can setup Apache to forward requests to Alkaline thus exposing an SSL front-end, so search can only be performed via SSL.

Modify httpd.conf to enable proxy:

<IfModule mod_proxy.c> ProxyRequests On ProxyPass /search http://www.search-srv.com:9999/ NoCache * </IfModule>

The VirtualHost directive should contain the same thing, here is an example:

<VirtualHost www.search-srv.com:443> ... ProxyPass /search http://www.search-srv.com:9999 </VirtualHost>

Add a directive for all requests to go through SSL:

<VirtualHost www.search-srv.com> ... Redirect permanent / https://www.search-srv.com/ RedirectMatch permanent (.*) https://www.search-srv.com/$1 </VirtualHost>

Add <!--SET SEARCH-BASE-HREF--https://www.search-srv.com/search--> to the search template.

This has been implemented, courtesy of InterNAP Network Services (http://www.internap.com/).