Things are rolling along on our XML-RPC library for PLT Scheme. At this point, the client is stable and well tested, and both the servlet and Apache CGI server implementations work and are poorly tested. However, one or two people were asking to make use of the server-side code, so we’ve made it available. Caveat developer.

Implementing an XML-RPC servlet is really quite straight-forward:

(require (planet "xmlrpc-servlet.ss"
("schematics" "xmlrpc.plt" 1 2)))

(define (add x y) (+ x y))
(add-handler 'math.add add)

(handle-xmlrpc-requests)

Dropping this code somewhere under the ‘/servlets’ directory should get you going. I’m still unhappy with the current state of the CGI code:

#!/path/to/mzscheme -gqr
(require (lib "config.ss" "planet"))
(PLANET-DIR "/tmp/PLaneTWeb/dir")
(CACHE-DIR "/tmp/PLaneTWeb/cache")
(LINKAGE-FILE "/tmp/PLaneTWeb/linkage")
(LOG-FILE #f)

(require (planet "xmlrpc-cgi.ss"
("schematics" "xmlrpc.plt" 1 2)))

(add-handler 'add (lambda (a b) (+ a b)))

(output-http-headers)

(handle-xmlrpc-requests)

I imagine we’ll absorb the output-http-headers into the handle-xmlrpc-requests macro, and I really want to do something to improve the state of affairs w.r.t. PLaneT package handling in the CGI environment. As I said above: the server code in the library is in motion, and it will likely change.

As an aside, I expect stress-testing the server-side code will be interesting; Noel suggested using Ethereal to record interactions between clients (in other languages) and our server implementations, and then replay those interactions in SchemeUnit unit tests. A neat idea, and not something I had thought of.