用twisted创建tcp socket长链接amf server服务

#Author:pako

 

#Email/gtalk:zealzpc@gmail.com

这是pyamf安装包里的例子，总的来说用pyamf来写server的各种例子还是很全的，包括django，gae，twisted，web2py等等，基本python常用的网络框架都有。现在很多网页游戏都是前端flash，那么和server端通信基本就用 amf了，如果server端的功能只是存储一些统计，或者对数据库的增删改查，那么一般的http短连接服务就能搞定了，以上提到的这些框架也都写起来比较简单，比如可以看django的例子http://www.pyamf.org/tutorials/gateways/django.html，寥寥数行就搞定了，python嘛。

 

 

  但有时候需求不是这样的需要flash和server保持一个长连接来不断的进行通信改怎么搞呢？此时在pyamf的网站上看到了sockey这一段，正是我们想要的。

 

  先看下server端的代码：server.py

 

 

# Copyright (c) The PyAMF Project.
# See LICENSE.txt for details.

"""
Example socket server using Twisted.

@see: U{Documentation for this example<http://pyamf.org/tutorials/actionscript/socket.html>}

@since: 0.1
"""


try:
    import twisted
except ImportError:
    print "This examples requires the Twisted framework. Download it from http://twistedmatrix.com"
    raise SystemExit

from twisted.internet.protocol import Protocol, Factory
from twisted.internet import reactor

from datetime import datetime
import pyamf


class TimerProtocol(Protocol):
    interval = 1.0 # 客户端链接到server后，server往客户端发送时间的间隔
    encoding = pyamf.AMF3
    timeout = 20 #客户端链接到server后多少时间不操作就断开链接的timeout

    def __init__(self):
        self.started = False
        #设置编码器
        self.encoder = pyamf.get_encoder(self.encoding)、
        #设置server端将数据编码成amf后存放的缓存地址
        self.stream = self.encoder.stream

    def connectionLost(self, reason):
        Protocol.connectionLost(self, reason)
        print "locst connection:",reason
        #客户端没断开一个链接，总连接数-1
        self.factory.number_of_connections -= 1
        print "number_of_connections:",self.factory.number_of_connections
    def connectionMade(self):
        #如果服务器连接数超过最大连接数，拒绝新链接建立
        if self.factory.number_of_connections >= self.factory.max_connections:
            self.transport.write('Too many connections, try again later')
            self.transport.loseConnection()

            return
        #总连接数+1
        self.factory.number_of_connections += 1
        self.timeout_deferred = reactor.callLater(TimerProtocol.timeout, self.transport.loseConnection)

    def dataReceived(self, data):
        #去除server收到client数据两端的空格
        data = data.strip()
        #如果收到的是'start'命令
        if data == 'start':
            # start sending a date object that contains the current time
            if not self.started:
                self.start()
        elif data == 'stop':
            self.stop()
        #每次执行完客户端请求后重置timeout，重新开始计算无操作时间。
        if self.timeout_deferred:
            self.timeout_deferred.cancel()
            self.timeout_deferred = reactor.callLater(TimerProtocol.timeout, self.transport.loseConnection)

    def start(self):
        self.started = True
        self.sendTime()

    def stop(self):
        self.started = False

    def sendTime(self):
        if self.started:
            #往缓存流里写入信息，用编码器进行amf编码
            self.encoder.writeElement(datetime.now())
            #返回给客户端编码后的信息
            self.transport.write(self.stream.getvalue())
            #重置缓存流
            self.stream.truncate()
            #每隔self.interval的时间再发送一次amf信息
            reactor.callLater(self.interval, self.sendTime)


class TimerFactory(Factory):
    protocol = TimerProtocol
    #最大链接数
    max_connections = 1000

    def __init__(self):
        self.number_of_connections = 0


class SocketPolicyProtocol(Protocol):
    """
    Serves strict policy file for Flash Player >= 9,0,124.
    
    @see: U{http://adobe.com/go/strict_policy_files}
    """
    def connectionMade(self):
        self.buffer = ''

    def dataReceived(self, data):
        self.buffer += data

        if self.buffer.startswith('<policy-file-request/>'):
            self.transport.write(self.factory.getPolicyFile(self))
            self.transport.loseConnection()


class SocketPolicyFactory(Factory):
    protocol = SocketPolicyProtocol

    def __init__(self, policy_file):
        """
        @param policy_file: Path to the policy file definition
        """
        self.policy_file = policy_file

    def getPolicyFile(self, protocol):
        return open(self.policy_file, 'rt').read()

#设置域名，端口。
host = 'localhost'
appPort = 8000
policyPort = 843
policyFile = 'socket-policy.xml'


if __name__ == '__main__':
    from optparse import OptionParser
    #设置server启动选项
    parser = OptionParser()
    parser.add_option("--host", default=host,
        dest="host", help="host address [default: %default]")
    parser.add_option("-a", "--app-port", default=appPort,
        dest="app_port", help="Application port number [default: %default]")
    parser.add_option("-p", "--policy-port", default=policyPort,
        dest="policy_port", help="Socket policy port number [default: %default]")
    parser.add_option("-f", "--policy-file", default=policyFile,
        dest="policy_file", help="Location of socket policy file [default: %default]")
    (opt, args) = parser.parse_args()

    print "Running Socket AMF gateway on %s:%s" % (opt.host, opt.app_port)
    print "Running Policy file server on %s:%s" % (opt.host, opt.policy_port)
     
    reactor.listenTCP(int(opt.app_port), TimerFactory(), interface=opt.host)
    reactor.listenTCP(int(opt.policy_port), SocketPolicyFactory(opt.policy_file),
                      interface=opt.host)
    reactor.run()

 

 

 

里面最主要干活的就是TimerProtocol这个类。

 

在例子中还提供了另外一个文件：time.tac。懂twisted的人应该就知道了，这是一份twistd脚本，可以直接通过twisted自带的twistd来执行。里面import了  server.py中已经写好的TimerFactory，然后定义了一个application类，这样就可以通过twistd命令来执行了，twistd是什么可以参考官方文档http://twistedmatrix.com/documents/current/core/howto/application.html 本文就不细说了。

 

debug模式启动server：twistd -noy timer.tac

 

daemo模式启动server：twistd -oy timer.tac

 

你也可以直接启动server.py文件：python server.py、

 

区别就是第二种直接后台运行了在linux，你看不到报错和调试信息，当然windows上不行。

 

 

 

# Copyright (c) The PyAMF Project.
# See LICENSE for details.

import sys, os

sys.path.append(os.getcwd())

from twisted.application import internet, service
from server import TimerFactory, SocketPolicyFactory
from server import appPort, policyPort


timer = TimerFactory()
policy = SocketPolicyFactory('socket-policy.xml')

# this is the important bit
application = service.Application('pyamf-socket-example')

timerService = internet.TCPServer(appPort, timer)
socketPolicyService = internet.TCPServer(policyPort, policy)

timerService.setServiceParent(application)
socketPolicyService.setServiceParent(application)

 

 

最后就是找个客户端来连接测测，例子里也提供了一个写好的flash，你打开通一个目录下的index.html就可以看看效果了。

 

 

 

  例子里也给你准备了python的客户端。

 

# Copyright (c) The PyAMF Project.
# See LICENSE for details.

"""
Python client for socket example.

@since: 0.5
"""


import socket
import pyamf

from server import appPort, host


class AmfSocketClient(object):
    def __init__(self):
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    def connect(self, host, port):
        print "Connecting to socket server on %s:%d" % (host, port)
        try:
            self.sock.connect((host, port))
            print "Connected to server.\n"
        except socket.error, e:
            raise Exception("Can't connect: %s" % e[1])

    def start(self):
        msg = ''

        # tell server we started listening
        print "send request: start"
        try:
            self.sock.send('start')
        except socket.error, e:
            raise Exception("Can't connect: %s" % e[1])

        while len(msg) < 1024:
            # read from server
            amf = self.sock.recv(1024)

            if amf == '':
                print "Connection closed."

            msg = msg + amf

            for obj in pyamf.decode(amf):
                print obj

        return msg

    def stop(self):
        print "send request: stop"
        self.sock.send('stop')


if __name__ == '__main__':
    from optparse import OptionParser

    parser = OptionParser()
    parser.add_option("-p", "--port", default=appPort,
        dest="port", help="port number [default: %default]")
    parser.add_option("--host", default=host,
        dest="host", help="host address [default: %default]")
    (options, args) = parser.parse_args()

    host = options.host
    port = int(options.port)

    client = AmfSocketClient()
    client.connect(host, port)

    try:
        client.start()
    except KeyboardInterrupt:
        client.stop()   

 原文地址：http://www.pyamf.org/tutorials/actionscript/socket.html

代码就在pyamf安装包的pyamf / doc / tutorials / examples / actionscript / socket这个目录里。

 

 

欢迎讨论。