WebService是一種跨編程語言和跨操作系統平台的遠程調用技術。
理解WebService
1.從表面上看，WebService就是一個應用程序向外界暴露出一個能通過Web進行調用的API，也就是說能用編程的方法通過Web來調用這個應用程序。我們把調用這個WebService的應用程序叫做客戶端，而把提供這個WebService的應用程序叫做服務端。
2.從深層次看，WebService是建立可互操作的分布式應用程序的新平台，是一個平台，是一套標准。它定義了應用程序如何在Web上實現互操作性，你可以用任何你喜歡的語言，在任何你喜歡的平台上寫Web service ，只要我們可以通過Web service標准對這些服務進行查詢和訪問。
Python 庫選擇
服務端開發：
針對Python的WebService開發，開發者討論最多的庫是soaplib（官方地址：http://soaplib.github.io/soaplib/2_0/index.html），但從其官網可知，其最新版本“soaplib-2.0.0-beta2”從2011年3月發布后就不再進行更新了。通過閱讀soaplib的官方文檔，可知其不再維護后已經轉向了一個新的項目：rpclib（官方地址：http://github.com/arskom/rpclib）進行后續開發，但在rpclib的readme中，介紹了rpclib已經更名為spyne，並將持續進行更新，so，那就選用spyne進行開發了。
spyne 官方文檔：http://spyne.io/docs/2.10/index.html
spyne github：https://github.com/arskom/spyne
- spyne 安裝：
pip install spyne
- lxml 安裝：
下載與python匹配的版本安裝包 https://pypi.python.org/pypi/lxml/3.6.0 進行安裝，如 lxml-3.6.0.win-amd64-py2.7.exe (md5)
客戶端開發：
客戶端調用WebService一般應用suds庫。
使用參考文檔：https://fedorahosted.org/suds/wiki/Documentation
- suds 安裝：
pip install suds
Spyne Introduction
Protocols：協議
Protocols define the rules for transmission of structured data
Transports:傳輸
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:接口文檔
Interface documents provide a machine-readable description of the expected input and output of the exposed method calls.
Serializers:序列化對象
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
服務端代碼實例（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()
服務端運行后，
訪問瀏覽器檢查服務 http://localhost:8000/?wsdl
瀏覽器中輸出wsdl文件：
客戶端調用（代碼實例）
#!/usr/bin/env python
# -*- coding: utf-8 -*-
from suds.client import Client # 導入suds.client 模塊下的Client類
wsdl_url = "http://localhost:8000/?wsdl"
def say_hello_test(url, name, times):
client = Client(url) # 創建一個webservice接口對象
client.service.say_hello(name, times) # 調用這個接口下的getMobileCodeInfo方法，並傳入參數
req = str(client.last_sent()) # 保存請求報文，因為返回的是一個實例，所以要轉換成str
response = str(client.last_received()) # 保存返回報文，返回的也是一個實例
print req # 打印請求報文
print response # 打印返回報文
if __name__ == '__main__':
say_hello_test(wsdl_url, 'Milton', 2)
客戶端運行后，
查看客戶端控制台可見輸出：
