一、简单介绍

为了解决在系统的80port提供RPC的服务。而又不影响正在运行的WEB服务。人们想出了用HTTP协议传输RPC包的办法。对于差点儿是专门用于传输文本的HTTP协议。要在其上传输RPC封包。最方便的方法莫过于把RPC封包编码成文本形式——比如XML文件。
XML- RPC（http://www.xml-rpc.com）是由美国UserLand公司指定的一个RPC协议。它将RPC信息封包编码为XML，然后通过 HTTP传输封包；
 简单的理解：
将数据定义为xml格式。通过http协议进行远程传输。

二、优点

1. 传输复杂的数据。
2. 通过程序语言的封装，实现远程对象的调用。

三、Python中xmlrpc应用
server端：

from SimpleXMLRPCServer import *
#import SimpleXMLRPCRequestHandler

def div(x,y):
    return x -y

class Math:
   def _listMethods(self):
        return [‘add‘,‘pow‘]

   def _methodHelp(self,method):
       if method == ‘add‘:
          return "add(2,3) =>5"
       elif method == ‘pow‘:
          return "pow(x,y[,z])=>number"
       else:
          return ""
    
   def _dispatch(self,method,params):
        if method == ‘pow‘:
           return pow(*params)
        elif method == ‘add‘:
           return params[0] + params[1]
        else:
           raise ‘bad method‘

server = SimpleXMLRPCServer(("localhost",8000))
# register_introspection_functions：Registers the XML-RPC introspection methods in the system namespace
server.register_introspection_functions()
server.register_function(div,"div")
server.register_function(lambda x,y:x*y,‘multiply‘)
server.register_instance(Math())
#serve_forever：Handle one request at a time until shutdown.  
#Polls for shutdown every poll_interval seconds. Ignores
#self.timeout. If you need to do periodic tasks, do them in
#another thread.
server.serve_forever()

client：

import xmlrpclib
s = xmlrpclib.ServerProxy(‘http://localhost:8000‘)
print(s.system.listMethods())

print(s.pow(2,3))
print(s.add(2,3))
print(s.div(3,2))
print(s.multiply(4,5))

执行情况：

[maokx@maokexu1 xmlrpc]$ python server.py

 /usr/lib64/python2.6/rfc822.py, readheaders, 131, enter readheaders
 /usr/lib64/python2.6/rfc822.py, readheaders, 205, exit readheaders
localhost.localdomain - - [16/Nov/2014 23:25:37] "POST /RPC2 HTTP/1.0" 200 -
 /usr/lib64/python2.6/rfc822.py, readheaders, 131, enter readheaders
 /usr/lib64/python2.6/rfc822.py, readheaders, 205, exit readheaders
localhost.localdomain - - [16/Nov/2014 23:25:37] "POST /RPC2 HTTP/1.0" 200 -
 /usr/lib64/python2.6/rfc822.py, readheaders, 131, enter readheaders
 /usr/lib64/python2.6/rfc822.py, readheaders, 205, exit readheaders
localhost.localdomain - - [16/Nov/2014 23:25:37] "POST /RPC2 HTTP/1.0" 200 -
 /usr/lib64/python2.6/rfc822.py, readheaders, 131, enter readheaders
 /usr/lib64/python2.6/rfc822.py, readheaders, 205, exit readheaders
localhost.localdomain - - [16/Nov/2014 23:25:37] "POST /RPC2 HTTP/1.0" 200 -
 /usr/lib64/python2.6/rfc822.py, readheaders, 131, enter readheaders
 /usr/lib64/python2.6/rfc822.py, readheaders, 205, exit readheaders
localhost.localdomain - - [16/Nov/2014 23:25:37] "POST /RPC2 HTTP/1.0" 200 -




 /usr/lib64/python2.6/rfc822.py, readheaders, 131, enter readheaders
 /usr/lib64/python2.6/rfc822.py, readheaders, 205, exit readheaders
localhost.localdomain - - [16/Nov/2014 23:25:45] "POST /RPC2 HTTP/1.0" 200 -
 /usr/lib64/python2.6/rfc822.py, readheaders, 131, enter readheaders
 /usr/lib64/python2.6/rfc822.py, readheaders, 205, exit readheaders
localhost.localdomain - - [16/Nov/2014 23:25:45] "POST /RPC2 HTTP/1.0" 200 -
 /usr/lib64/python2.6/rfc822.py, readheaders, 131, enter readheaders
 /usr/lib64/python2.6/rfc822.py, readheaders, 205, exit readheaders
localhost.localdomain - - [16/Nov/2014 23:25:45] "POST /RPC2 HTTP/1.0" 200 -
 /usr/lib64/python2.6/rfc822.py, readheaders, 131, enter readheaders
 /usr/lib64/python2.6/rfc822.py, readheaders, 205, exit readheaders
localhost.localdomain - - [16/Nov/2014 23:25:45] "POST /RPC2 HTTP/1.0" 200 -
 /usr/lib64/python2.6/rfc822.py, readheaders, 131, enter readheaders
 /usr/lib64/python2.6/rfc822.py, readheaders, 205, exit readheaders
localhost.localdomain - - [16/Nov/2014 23:25:45] "POST /RPC2 HTTP/1.0" 200 -


[maokx@maokexu1 xmlrpc]$ python client.py 
[‘add‘, ‘div‘, ‘multiply‘, ‘pow‘, ‘system.listMethods‘, ‘system.methodHelp‘, ‘system.methodSignature‘]
8
5
1
20
[maokx@maokexu1 xmlrpc]$ python client.py 
[‘add‘, ‘div‘, ‘multiply‘, ‘pow‘, ‘system.listMethods‘, ‘system.methodHelp‘, ‘system.methodSignature‘]
8
5
1
20
[maokx@maokexu1 xmlrpc]$