one of the little annoyances with using libhtdb for CGI writing
is the whole if/elseif/elseif/.../else mapping of URIs to the
actual called routines. for example, we do a lot of the following:
if (htdb_equal("page", "blah.html"))
resource = doBlah();
else (htdb_equal("page", "buh.html"))
resource = doBuh();
this method is easy for a newcomer to "get".
but recognize there is a distinct mapping occurring between
a URI and a distinct function called - and this mapping is hardcoded.
i'm toying with the idea of moving the URI/function mapping handling into the
core of libhtdb. in such a world, all "handler functions" would be some
form of a DSO, and there would be an external/configurable .htdb file
mapping between URIs and called functions.
in such a world, there would be a single, quite simple CGI whose behavior
is to lookup the mapping between a URI and a called function. if no such
mapping exists, then it falls back to the simple "static document" lookup
employed by the htdb CGI itself.
- runtime start-up would be quicker, as the executable would be tiny.
- flexible realtime mapping of URIs to handlers.
- potentially smaller runtime executable, as the size would grow
as only the more common handler DSOs are sucked-in.
(handleX.o would become handleX.so - no more static linking)
- the external list of mappings would allow for a definitive
"state map" - testing could be somewhat automated.
- recompile a single DSO instead of a full CGI - realtime bugfixes,
er, i mean feature additions,
may be less intrusive.
- maintaining the external mapping is a manual process
- to the uninitiated, this method would one step further from procedural
programming - it may appear more confusing than a bunch of if/then/elses.
what got me started on this...
i was mulling over that fact that CGIs are simply state machines - if you have
the right set of input, you will drop down into a known handler. this led to
the notion of the need for a more formal state engine handler - we're basically
asking "give me object X", so there should be an easy way to know how to give
X instead of following code logic to determine the right handler.
Sun Jan 6 19:49:09 PST 2002