Besides RAILS, I’m very interested in the Ruby language. I’m also curious how to setup a very simple XMLRPC server. I know WEBrick is a pretty stable and very extensible webserver (written in Ruby), as it can also run the RAILS software.

Below are two very simple little Ruby programs, one is the client, one is the server. The server is capable of adding, substracting, dividing & multiplying two numbers. It is also capable of throwing an error in case you try to divide by zero.

The client is capable of error handling. This should be a very simple starting point from which you can addon to build your own XMLRPC server.

require "webrick"
require "xmlrpc/server"

class SimpleXMLRPC < XMLRPC::WEBrickServlet
  def add( a, b )
    a + b
  end
  def sub( a, b )
    a - b
  end
  def div( a, b )
    if b == 0
      raise XMLRPC::FaultException.new(1, "Division by zero")
    else
      a / b 
    end
  end
  def mul( a, b )
    a * b
  end
end

h = SimpleXMLRPC.new 
h.add_handler( "api", h )

httpserver = WEBrick::HTTPServer.new(:Port => 8080)    
httpserver.mount("/", h)
trap("HUP") { httpserver.shutdown }   
httpserver.start

require "xmlrpc/client"

# Make an object to represent the XML-RPC server.
server = XMLRPC::Client.new( "localhost", "/", 8080 )

# Call the xmlrpc server to try and add two numbers
begin
  result = server.call("api.add", 5, 3)
  puts "Sum of 5 & 3: #{result}"
rescue XMLRPC::FaultException => e
  puts "Error:"
  puts e.faultCode
  puts e.faultString
end

# Call the xmlrpc server to try and divide two numbers
begin
  result = server.call("api.div", 5, 0)
  puts "Division of 5 & 0: #{result}"
rescue XMLRPC::FaultException => e
  puts "Error:"
  puts e.faultCode
  puts e.faultString
end