用twisted创建tcp socket长链接amf server服务
#Author:pako
#Email/gtalk:[email protected]
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}
@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('
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。