XML-RPC

XML-RPC is a neat way to send messages across the Internet.

The neat thing about XML-RPC is that it transports native data structures- you can ship off lists, strings, dictionaries, and numbers.

You can [wiki:Wiki/XmlRpc read more about it over on C2,] or on [http://www.xmlrpc.com/ the XML-RPC home page.]

Sample Code

   1 import xmlrpclib
   2 
   3 XMLRPC_SERVER_URL = "http://www.python.org/cgi-bin/moinmoin/?action=xmlrpc"
   4 
   5 pythoninfo = xmlrpclib.ServerProxy( XMLRPC_SERVER_URL )
   6 allpages = pythoninfo.getAllPages() # this is the XML-RPC call
   7 
   8 print ", ".join( allpages )

This code calls the PythonInfo wiki, and receives the TitleIndex as a list.

Message Format

If you can communicate strings, you can do XML-RPC. You could even do it by e-mail!

Here's how to make your string:

   1 import xmlrpclib
   2 
   3 func_name = "foo"
   4 arg_1 = "robot"
   5 arg_2 = { "some":1, "dict":2 }
   6 arg_3 = [1,2,3,4,5]
   7 
   8 call_string = xmlrpclib.dumps( (arg_1,arg_2,arg_3,), func_name )

...resulting in the following call_string value:

<?xml version='1.0'?>
<methodCall>
<methodName>foo</methodName>
<params>
<param>
<value><string>robot</string></value>
</param>
<param>
<value><struct>
<member>
<name>dict</name>
<value><int>2</int></value>
</member>
<member>
<name>some</name>
<value><int>1</int></value>
</member>
</struct></value>
</param>
<param>
<value><array><data>
<value><int>1</int></value>
<value><int>2</int></value>
<value><int>3</int></value>
<value><int>4</int></value>
<value><int>5</int></value>
</data></array></value>
</param>
</params>
</methodCall>

...which can then be turned back into Python data:

   1 call_data = xmlrpclib.loads( call_string )

...which then builds:

(('robot', {'some': 1, 'dict': 2}, [1, 2, 3, 4, 5]), u'foo')

That is, the first item is the arguments tuple, and the second item is the name of the function.

The capabilities are described under "Convenience Functions" in [http://docs.python.org/lib/module-xmlrpclib.html the xmlrpclib documentation.]

See Also

• [http://docs.python.org/lib/xmlrpc-client-example.html official xmlrpclib example]

• [http://docs.python.org/lib/module-xmlrpclib.html xmlrpclib documentation]

• [http://www.onlamp.com/pub/a/python/2001/01/17/xmlrpcserver.html XML-RPC: It Works Both Ways (onlamp.com)]

• DocXmlRpcServer - class to help make an XML-RPC server

• [http://effbot.org/zone/xmlrpc-cgi.htm Providing XML-RPC Services via CGI]