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3..Twisted学习

py3study

发布于 2020-01-20 08:44:11

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代码可运行

文章被收录于专栏：python3python3

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代码可运行

写这个主要是为了自己理解Twisted的文档

建立一个finger服务

你不需要调用Twisted，Twisted会自己运行。reactor是Twisted的主循环，想python的其他主循环一样。每个Twisted只有一个reactor。一旦启动他就会不停的运行下去，响应一个又一个请求。

from twisted.internet import reactor返回当前的reactor。如果你不选择一个reactor的话，它会默认选择。

 1 from twisted.internet import protocol, reactor, endpoints
 2 
 3 class FingerProtocol(protocol.Protocol):
 4     pass
 5 
 6 class FingerFactory(protocol.ServerFactory):
 7     protocol = FingerProtocol
 8 
 9 fingerEndpoint = endpoints.serverFromString(reactor, "tcp:1079")
10 fingerEndpoint.listen(FingerFactory())
11 reactor.run()

这个流程看过前两章的应该很熟悉了，先创建协议，再创建工厂，然后主循环。

 1 from twisted.internet import protocol, reactor, endpoints
 2 
 3 class FingerProtocol(protocol.Protocol):
 4     def connectionMade(self):
 5         self.transport.loseConnection()
 6 
 7 class FingerFactory(protocol.ServerFactory):
 8     protocol = FingerProtocol
 9 
10 fingerEndpoint = endpoints.serverFromString(reactor, "tcp:1079")
11 fingerEndpoint.listen(FingerFactory())
12 reactor.run()

这个是增加了一个连接之后的初始化配置

 1 from twisted.internet import protocol, reactor, endpoints
 2 from twisted.protocols import basic
 3 
 4 class FingerProtocol(basic.LineReceiver):
 5     def lineReceived(self, user):
 6         self.transport.loseConnection()
 7 
 8 class FingerFactory(protocol.ServerFactory):
 9     protocol = FingerProtocol
10 
11 fingerEndpoint = endpoints.serverFromString(reactor, "tcp:1079")
12 fingerEndpoint.listen(FingerFactory())
13 reactor.run()

这个是按行读取数据，就是按照你的\r\n读取数据，之后关闭连接

写一个读取用户名，返回错误，断开连接的finger

 1 from twisted.internet import protocol, reactor, endpoints
 2 from twisted.protocols import basic
 3 
 4 class FingerProtocol(basic.LineReceiver):
 5     def lineReceived(self, user):
 6         self.transport.write(b"No such user\r\n")
 7         self.transport.loseConnection()
 8 
 9 class FingerFactory(protocol.ServerFactory):
10     protocol = FingerProtocol
11 
12 fingerEndpoint = endpoints.serverFromString(reactor, "tcp:1079")
13 fingerEndpoint.listen(FingerFactory())
14 reactor.run()

这个就是按行读取，返回一句话，之后关闭连接

 1 from twisted.internet import protocol, reactor, endpoints
 2 from twisted.protocols import basic
 3 
 4 class FingerProtocol(basic.LineReceiver):
 5     def lineReceived(self, user):
 6         self.transport.write(self.factory.getUser(user)+ b"\r\n")
 7         self.transport.loseConnection()
 8 
 9 class FingerFactory(protocol.ServerFactory):
10     protocol = FingerProtocol
11 
12     def getUser(self, user):
13         return b"No such user"
14 
15 fingerEndpoint = endpoints.serverFromString(reactor, "tcp:1079")
16 fingerEndpoint.listen(FingerFactory())
17 reactor.run()

增加获取用户名的函数

在协议之中调用工厂方法，可以用self.factory，这个就是指向工厂的，因为工厂类实际上是它的父类。

 1 from twisted.internet import protocol, reactor, endpoints
 2 from twisted.protocols import basic
 3 
 4 class FingerProtocol(basic.LineReceiver):
 5     def lineReceived(self, user):
 6         self.transport.write(self.factory.getUser(user) + b"\r\n")
 7         self.transport.loseConnection()
 8 
 9 class FingerFactory(protocol.ServerFactory):
10     protocol = FingerProtocol
11 
12     def __init__(self, users):
13         self.users = users
14 
15     def getUser(self, user):
16         return self.users.get(user, b"No such user")
17 
18 fingerEndpoint = endpoints.serverFromString(reactor, "tcp:1079")
19 fingerEndpoint.listen(FingerFactory({ b'moshez' : b'Happy and well'}))
20 reactor.run()

初始化一个字典，如果你输入的用户名没有在字典里边，就会返回默认值。

Defereds

 1 from twisted.internet import protocol, reactor, defer, endpoints
 2 from twisted.protocols import basic
 3 
 4 class FingerProtocol(basic.LineReceiver):
 5     def lineReceived(self, user):
 6         d = self.factory.getUser(user)
 7 
 8         def onError(err):
 9             return 'Internal error in server'
10         d.addErrback(onError)
11 
12         def writeResponse(message):
13             self.transport.write(message + b'\r\n')
14             self.transport.loseConnection()
15         d.addCallback(writeResponse)
16 
17 class FingerFactory(protocol.ServerFactory):
18     protocol = FingerProtocol
19 
20     def __init__(self, users):
21         self.users = users
22 
23     def getUser(self, user):
24         return defer.succeed(self.users.get(user, b"No such user"))
25 
26 fingerEndpoint = endpoints.serverFromString(reactor, "tcp:1079")
27 fingerEndpoint.listen(FingerFactory({b'moshez': b'Happy and well'}))
28 reactor.run()

在这个里边，我么使用了defer，其实也就仅仅修改了getUser方法。Defereds循序由事件驱动程序，也就是说，如果程序中的一个任务正在等待数据，程序可以去执行其他操作，这叫做异步执行。

上边的代码测试了一下，是按照队列执行的，就是说两个客户端发送数据，如果第一个客户端设置延迟返回5秒，那么之后5秒后，第二个客户端才会被响应。

解释一下deferred：

大家可以去看

https://www.cnblogs.com/zhangjing0502/archive/2012/05/16/2504415.html 作者：很多不懂呀。。

Twisted

 1 from twisted.application import service, strports
 2 from twisted.internet import protocol, reactor, defer
 3 from twisted.protocols import basic
 4 
 5 class FingerProtocol(basic.LineReceiver):
 6     def lineReceived(self, user):
 7         d = self.factory.getUser(user)
 8 
 9         def onError(err):
10             return 'Internal error in server'
11         d.addErrback(onError)
12 
13         def writeResponse(message):
14             self.transport.write(message + b'\r\n')
15             self.transport.loseConnection()
16         d.addCallback(writeResponse)
17 
18 class FingerFactory(protocol.ServerFactory):
19     protocol = FingerProtocol
20 
21     def __init__(self, users):
22         self.users = users
23 
24     def getUser(self, user):
25         return defer.succeed(self.users.get(user, b"No such user"))
26 
27 application = service.Application('finger', uid=1, gid=1)
28 factory = FingerFactory({b'moshez': b'Happy and well'})
29 strports.service("tcp:79", factory, reactor=reactor).setServiceParent(
30     service.IServiceCollection(application))