From: James Britt <jamesUNDERBARb@...>
Date: 2004-07-03T01:25:22+09:00
Subject: Re: XMLRPC::CGIServer nuby

Kent Sibilev wrote:

> I think that XMLRPC:CGIServer is just another way to setup your XMLRPC 
> Server. Meaning that your XMLRPC requests will go through some CGI 
> capable web server like Apache, which invokes  your XMLRPC:CGIServer.
> 

This is some untested code assembled from some other code I've used in 
Blogtari.

When given an xml-rpc request "someName.someMethod", along with its 
arguments, it tries to dynamically load the class SomeName (assumed to 
be in a file called SomeName.rb someplace in the 'require' path) and 
then invokes someMethod.

So, to implement fooBar.add, with 2 args, you need to provide a class 
FooBar with a method add( x, y), and put it in a file called FooBar.rb

(There's also a bit of code that checks to see if tis is running under 
mod_ruby.)


One neat trick you can do with this arrangement is write an XML-RPC 
method that takes a code string and file name as arguments, and have it 
write out a new ruby file on the server.  Then you can add new, or 
modify existing, XML-RPC functions using XML-RPC.

Some security checks might be a good idea, though.

#!/usr/local/bin/ruby
# File index.rb

require "xmlrpc/server"
# You may also want to munge $: to ensure it
# can find your request handler files.

s = XMLRPC::CGIServer.new

if defined? Apache
   s = XMLRPC::ModRubyServer.new
end


def new_from_name( classname, *args)
   cname = String.new( classname.untaint )
   obj = nil
   begin
     obj = Object.const_get( cname ).new( *args )
     rescue Exception
     begin
       require cname
       obj = Object.const_get( cname ).new( *args )
     rescue Exception
       raise "Cannot create object #{cname}: #{$!}" unless obj
     end
   end
   obj
end

def call_dynamic( name, *args )
   cname, mname = name.split( '.')
   begin
     handler = new_from_name( class_name_it( cname )  )
     return handler.send( mname, *args)
   rescue
     raise  "#{cname}::#{mname} is not implemented: #{$!}"
   end
end


s.set_default_handler do |name, *args|
   begin
     call_dynamic( name,  *args )
   rescue Exception
     raise XMLRPC::FaultException.new(-99, "#{$!}")
   end
end

s.serve