Python 开发与测试 Webservice（SOAP）

WebService是一种跨编程语言和跨操作系统平台的远程调用技术。

理解WebService

1.从表面上看，WebService就是一个应用程序向外界暴露出一个能通过Web进行调用的API，也就是说能用编程的方法通过Web来调用这个应用程序。我们把调用这个WebService的应用程序叫做客户端，而把提供这个WebService的应用程序叫做服务端。

2.从深层次看，WebService是建立可互操作的分布式应用程序的新平台，是一个平台，是一套标准。它定义了应用程序如何在Web上实现互操作性，你可以用任何你喜欢的语言，在任何你喜欢的平台上写Web service ，只要我们可以通过Web service标准对这些服务进行查询和访问。

Python 库选择

服务端开发：

针对Python的WebService开发，开发者讨论最多的库是soaplib（官方地址：http://soaplib.github.io/soaplib/2_0/index.html），但从其官网可知，其最新版本“soaplib-2.0.0-beta2”从2011年3月发布后就不再进行更新了。通过阅读soaplib的官方文档，可知其不再维护后已经转向了一个新的项目：rpclib（官方地址：http://github.com/arskom/rpclib）进行后续开发，但在rpclib的readme中，介绍了rpclib已经更名为spyne，并将持续进行更新，so，那就选用spyne进行开发了。

spyne 官方文档：http://spyne.io/docs/2.10/index.html

spyne github：https://github.com/arskom/spyne

• spyne 安装：

pip install spyne

• lxml 安装：

下载与python匹配的版本安装包  https://pypi.python.org/pypi/lxml/3.6.0 进行安装，如 lxml-3.6.0.win-amd64-py2.7.exe (md5)

客户端开发：

客户端调用WebService一般应用suds库。

使用参考文档：https://fedorahosted.org/suds/wiki/Documentation

• suds 安装：

pip install suds

Spyne Introduction

Protocols：协议
　　Protocols define the rules for transmission of structured data
Transports:传输
　　Transports, also protocols themselves, encapsulate protocol data in their free-form data sections.
Models:模式
　　Types like Unicode, Integer or ByteArray are all models. They reside in the spyne.model package.
Interface Documents:接口文档
　　Interface documents provide a machine-readable description of the expected input and output of the exposed method calls. 
Serializers:序列化对象
　　Serializers are currently not distinguished in Spyne code. They are the protocol-specific representations of a serialized Python object.

How your code is wrapped？

step1:Your code is inside @rpc-wrapped methods in ServiceBase subclasses.

step2:The ServiceBase subclasses in turn are wrapped by an Application instance.

The Application instantiation is used to assign input and output protocols to the exposed methods.

step3:The Application instance is finally wrapped by a client or server transport that takes the responsibility of moving the bits around.

step4:Deploying the service using Soap via Wsgi

服务端代码实例（HelloWorld）

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
preference:
    http://spyne.io/docs/2.10/index.html
    https://github.com/arskom/spyne/blob/master/examples/helloworld_soap.py

This is a simple HelloWorld example to show the basics of writing
a webservice using spyne, starting a server, and creating a service
client.
Here's how to call it using suds:

#>>> from suds.client import Client
#>>> hello_client = Client('http://localhost:8000/?wsdl')
#>>> hello_client.service.say_hello('punk', 5)
(stringArray){
   string[] =
      "Hello, punk",
      "Hello, punk",
      "Hello, punk",
      "Hello, punk",
      "Hello, punk",
 }
#>>>

"""
# Application is the glue between one or more service definitions, interface and protocol choices.
from spyne import Application
# @rpc decorator exposes methods as remote procedure calls
# and declares the data types it accepts and returns
from spyne import rpc
# spyne.service.ServiceBase is the base class for all service definitions.
from spyne import ServiceBase
# The names of the needed types for implementing this service should be self-explanatory.
from spyne import Iterable, Integer, Unicode

from spyne.protocol.soap import Soap11
# Our server is going to use HTTP as transport, It’s going to wrap the Application instance.
from spyne.server.wsgi import WsgiApplication

# step1: Defining a Spyne Service
class HelloWorldService(ServiceBase):
    @rpc(Unicode, Integer, _returns=Iterable(Unicode))
    def say_hello(self, name, times):
        """Docstrings for service methods appear as documentation in the wsdl.
        <b>What fun!</b>
        @param name: the name to say hello to
        @param times: the number of times to say hello
        @return  When returning an iterable, you can use any type of python iterable. Here, we chose to use generators.
        """

        for i in range(times):
            yield u'Hello, %s' % name

# step2: Glue the service definition, input and output protocols
soap_app = Application([HelloWorldService], 'spyne.examples.hello.soap',
                       in_protocol=Soap11(validator='lxml'),
                       out_protocol=Soap11())

# step3: Wrap the Spyne application with its wsgi wrapper
wsgi_app = WsgiApplication(soap_app)

if __name__ == '__main__':
    import logging

    from wsgiref.simple_server import make_server

    # configure the python logger to show debugging output
    logging.basicConfig(level=logging.DEBUG)
    logging.getLogger('spyne.protocol.xml').setLevel(logging.DEBUG)

    logging.info("listening to http://127.0.0.1:8000")
    logging.info("wsdl is at: http://localhost:8000/?wsdl")

    # step4:Deploying the service using Soap via Wsgi
    # register the WSGI application as the handler to the wsgi server, and run the http server
    server = make_server('127.0.0.1', 8000, wsgi_app)
    server.serve_forever()

服务端运行后，

访问浏览器检查服务  http://localhost:8000/?wsdl

浏览器中输出wsdl文件：

客户端调用（代码实例）

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from suds.client import Client  # 导入suds.client 模块下的Client类

wsdl_url = "http://localhost:8000/?wsdl"

def say_hello_test(url, name, times):
    client = Client(url)                    # 创建一个webservice接口对象
    client.service.say_hello(name, times)   # 调用这个接口下的getMobileCodeInfo方法，并传入参数
    req = str(client.last_sent())           # 保存请求报文，因为返回的是一个实例，所以要转换成str
    response = str(client.last_received())  # 保存返回报文，返回的也是一个实例
    print req       # 打印请求报文
    print response  # 打印返回报文

if __name__ == '__main__':
    say_hello_test(wsdl_url, 'Milton', 2)

客户端运行后，

查看客户端控制台可见输出：

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