The server that we distribute as WWWDaemon is in two parts: a common HTDaemon program taking care of the communications, and a variable HTRetrieve function called by HTDaemon with the significant part of the address (i.e. after host) split as argument and keywords (look at the code). The default HTRetrieve function, located in HTRetrieve.c, only knows about finding files and sending them. To make an index server, you need an HTRetrieve that knows how to query a database, or otherwise find info, from keywords supplied after the '?' in the address. It can be as simple as a 'grep' in a series of files.
We provide 3 example index servers built this way: VMSHelpGate, which gives access to VMS help, FindGate which gives access to a mainframe search engine called XFind, and WAISGate, which speaks the WAIS protocol to contact their search engines. You can read about all this in the Web...
Oh yes, the ISINDEX tag should be returned by the server to notify the client that it accepts searches.
Page under construction.
Tim BL