python远程调用rpc模块xmlrpclib的方法
作者:comprel
RPC(Remote Procedure Call Protocol)是远程调用协议,它通过网络请求服务到远端服务器,服务器根据请求做出响应,将结果返回
它是一种C/S模式,客户端可以调用远程服务器上的参数(类似URL)并返回结果
利用rpc可以实现系统的分布式架构,可以将功能分解到多台服务器上进行实现,同时也将也可以将负载打散,分布到不同服务器上,整合计算资源
在openstack中就大量使用了rpc
rpc多使用http传输请求,格式有xml,json等,这里是xml
模块:
xmlrpclib
注:xmlrpclib模块在python3中重命名为xmlrpc.client
xmlrpc并不是很安全,但在2.7.9 https url中默认加入了证书,主机名验证
定义:
class xmlrpclib.ServerProxy(uri[, transport[, encoding[, verbose[, allow_none[, use_datetime[, context]]]]]])
1.uri,即服务端的url地址
2.transport 传输实例,可选,https urls/http
3.encoding
4.verbose 是debug模式
5.allow_none 是否请求空 ,若为True,那么常量none将被翻译成xml,默认如果是none则抛出异常 TypeError
6.use_datetime 可以使用date/time values记录调用时间datetime.datetime,默认是false
ServerProxy对象提供一些默认的方法:
1.ServerProxy.system.listMethods() 返回远端服务器方法列表
2.ServerProxy.system.methodSignature(name) 方法签名,是一个数组类型
3.ServerProxy.system.methodHelp(name) 方法帮助信息
例如一个简单的示例:
服务端:
import xmlrpclib from SimpleXMLRPCServer import SimpleXMLRPCServer def get_power(n,m): return n**m server = SimpleXMLRPCServer(("0.0.0.0", 8081)) print "start service get power on 0.0.0.0 8081..." server.register_function(get_power, "get_power") server.serve_forever()
客服端:
import xmlrpclib server_power = xmlrpclib.ServerProxy("http://192.168.137.9:8081/") print "3**2 = %d" %(server_power.get_power(3,2)) print "2**5 = %d" %(server_power.get_power(2,5))
结果:
服务端:
# python xml_server.py start service get power on 0.0.0.0 8081... 192.168.137.9 - - [22/May/2017 10:37:47] "POST / HTTP/1.1" 200 - 192.168.137.9 - - [22/May/2017 10:37:47] "POST / HTTP/1.1" 200 -
客服端:
# python xml_client.py 3**2 = 9 2**5 = 32
xmlrpclib提供的一些方法:
class xmlrpclib.DateTime 时间对象
例如:
服务端:
import datetime from SimpleXMLRPCServer import SimpleXMLRPCServer import xmlrpclib def today(): today = datetime.datetime.today() return xmlrpclib.DateTime(today) server = SimpleXMLRPCServer(("0.0.0.0", 8081)) print "start service on 0.0.0.0 8081..." server.register_function(today, "today") server.serve_forever()
客服端:
import xmlrpclib import datetime s = xmlrpclib.ServerProxy("http://192.168.137.9:8081/") today = s.today() converted = datetime.datetime.strptime(today.value, "%Y%m%dT%H:%M:%S") print "Today: %s" % converted.strftime("%d.%m.%Y, %H:%M")
结果:
服务端
# python rpc_time.py start service on 0.0.0.0 8081... 192.168.137.9 - - [22/May/2017 10:43:19] "POST / HTTP/1.1" 200 -
客服端:
# python rpc_time_client.py Today: 22.05.2017, 10:43
2.class xmlrpclib.Binary 二进制对象
3.class xmlrpclib.Fault fault对象
如:
客服端:
import xmlrpclib s = xmlrpclib.ServerProxy("http://192.168.137.9:8081/") try: s.add(2, 5) except xmlrpclib.Fault as err: print "A fault occurred" print "Fault code: %d" % err.faultCode print "Fault string: %s" % err.faultString
class xmlrpclib.MultiCall(server) 提供多个调用,复合调用:
例如:
from SimpleXMLRPCServer import SimpleXMLRPCServer def add(x,y): return x+y def subtract(x, y): return x-y def multiply(x, y): return x*y def divide(x, y): return x/y def get_power(n,m): return n**m server = SimpleXMLRPCServer(("0.0.0.0", 8081)) print "start service on 0.0.0.0 8081..." server.register_multicall_functions() server.register_function(add, 'add') server.register_function(subtract, 'subtract') server.register_function(multiply, 'multiply') server.register_function(divide, 'divide') server.register_function(get_power, 'get_power') server.serve_forever()
客服端:
import xmlrpclib s = xmlrpclib.ServerProxy("http://192.168.137.9:8081/") multicall = xmlrpclib.MultiCall(s) multicall.add(7,3) multicall.subtract(7,3) multicall.multiply(7,3) multicall.divide(7,3) multicall.get_power(7,3) result = multicall() print "7+3=%d, 7-3=%d, 7*3=%d, 7/3=%d 7**3=%d" % tuple(result)
服务端:
# python mul_xmlserver.py start service on 0.0.0.0 8081... 192.168.137.9 - - [22/May/2017 10:51:59] "POST / HTTP/1.1" 200 -
客服端:
# python mul_xmlclient.py 7+3=10, 7-3=4, 7*3=21, 7/3=2 7**3=343
另外xmlrpc还提供有比较快捷的函数:
1.xmlrpclib.boolean(value) 将任意的python值转换成xmlrpc的布尔类型True/False
2.xmlrpclib.dumps(params[, methodname[, methodresponse[, encoding[, allow_none]]]])
params请求转换为xml
3.xmlrpclib.loads(data[, use_datetime])
将一个xml-rpc的请求转换成python对象
例如:
from xmlrpclib import ServerProxy, Error server = ServerProxy("http://betty.userland.com") print server try: print server.examples.getStateName(41) except Error as err: print "ERROR", err
客服端:
import xmlrpclib, httplib class ProxiedTransport(xmlrpclib.Transport): def set_proxy(self, s): self.s = s def make_connection(self, host): self.realhost = host h = httplib.HTTPConnection(self.s) return h def send_request(self, connection, handler, request_body): connection.putrequest("POST", 'http://%s%s' % (self.realhost, handler)) def send_host(self, connection, host): connection.putheader('Host', self.realhost) p = ProxiedTransport() p.set_proxy('proxy-server:8080') server = xmlrpclib.ServerProxy('http://time.xmlrpc.com/RPC2', transport=p) print server.currentTime.getCurrentTime()
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