本文采取了简单的协议定制，定义了五条命令，指令Head如下：
Sync：标识开始同步文件夹
End：标识结束同步
File：标识传输的文件名（相对路径）
Folder：标志文件夹（相对路径）
None：文件内容

每条命令以CMB_BEGIN开始，以CMB_END结束。

客户端需要对接收缓冲做解析，取出一条一条的指令，然后根据指令的Head做相应的处理，比如创建文件夹、写入文件等。

下面是服务端的代码：

from twisted.internet import reactor
from twisted.internet.protocol import Protocol,Factory
from twisted.protocols.basic import LineReceiver
import os
import struct
 
BUFSIZE = 4096
 
class SimpleLogger(Protocol):
 def connectionMade(self):
 print 'Got connection from', self.transport.client
 
 def connectionLost(self, reason):
 print self.transport.client, 'disconnected'
 
 def dataReceived(self, line):
 print line
 self.transport.write("Hello Client, I am the Server!
")
 
 self.transport.write("CMB_BEGIN")
 self.transport.write("Sync")
 self.transport.write("CMB_END")
 self.send_file_folder('server')
 
 def send_file_folder(self,folder):
 '''send folder to the client'''
 for f in os.listdir(folder):
 sourceF = os.path.join(folder, f)
 if os.path.isfile(sourceF): 
 print 'File:',sourceF[7:]
 self.transport.write("CMB_BEGIN")
 self.transport.write("File:" + sourceF[7:])
 self.transport.write("CMB_END")
 fp = open(sourceF,'rb')
 while 1:
 filedata = fp.read(BUFSIZE)
 if not filedata: break
 else:
 self.transport.write("CMB_BEGIN")
 self.transport.write(filedata)
 print 'send size:::::::::',len(filedata)
 self.transport.write("CMB_END")
 fp.close()
 self.transport.write("CMB_BEGIN")
 self.transport.write("End")
 self.transport.write("CMB_END")
 if os.path.isdir(sourceF):
 print 'Folder:',sourceF[7:]
 self.transport.write("CMB_BEGIN")
 self.transport.write("Folder:" + sourceF[7:])
 self.transport.write("CMB_END")
 self.send_file_folder(sourceF)
 
factory = Factory()
factory.protocol = SimpleLogger
reactor.listenTCP(1234, factory)
reactor.run()

Server在收到Client的某个信号之后(此代码中，当Client随便向Server发送任何内容都可)，Server即会调用send_file_folder将sever文件夹下的内容全部发送给客户端。

服务端运行结果如下：

下面是客户端的代码：

from twisted.internet.selectreactor import SelectReactor
from twisted.internet.protocol import Protocol,ClientFactory
from twisted.protocols.basic import LineReceiver
import os
from struct import *
 
reactor = SelectReactor()
protocol = Protocol()
prepare = 0
filename = ""
sourceDir = 'client'
recvBuffer = ''
 
def delete_file_folder(src):
 '''delete files and folders'''
 if os.path.isfile(src):
 try:
 os.remove(src)
 except:
 pass
 elif os.path.isdir(src):
 for item in os.listdir(src):
 itemsrc = os.path.join(src,item)
 delete_file_folder(itemsrc) 
 try:
 os.rmdir(src)
 except:
 pass
 
def clean_file_folder(src):
 '''delete files and child folders'''
 delete_file_folder(src)
 os.mkdir(src)
 
def writefile(filename,data):
 print 'write file size:::::::::',len(data)
 fp = open(filename,'a+b')
 fp.write(data)
 fp.close()
 
class QuickDisconnectedProtocol(Protocol):
 def connectionMade(self):
 print "Connected to %s."%self.transport.getPeer().host
 self.transport.write("Hello server, I am the client!
")
 def dataReceived(self, line):
 global prepare
 global filename
 global sourceDir
 global recvBuffer
 
 recvBuffer = recvBuffer + line
 self.processRecvBuffer()
 
 def processRecvBuffer(self):
 global prepare
 global filename
 global sourceDir
 global recvBuffer
 
 while len(recvBuffer) > 0 :
 index1 = recvBuffer.find('CMB_BEGIN')
 index2 = recvBuffer.find('CMB_END')
 
 if index1 >= 0 and index2 >= 0:
 line = recvBuffer[index1+9:index2]
 recvBuffer = recvBuffer[index2+7:]
 
 if line == 'Sync':
 clean_file_folder(sourceDir)
 
 if line[0:3] == "End":
 prepare = 0
 elif line[0:5] == "File:":
 name = line[5:]
 filename = os.path.join(sourceDir, name)
 print 'mk file:',filename
 prepare = 1
 elif line[0:7] == "Folder:":
 name = line[7:]
 filename = os.path.join(sourceDir, name)
 print 'mkdir:',filename
 os.mkdir(filename)
 elif prepare == 1:
 writefile(filename,line)
 else:
 break
 
class BasicClientFactory(ClientFactory):
 protocol=QuickDisconnectedProtocol
 def clientConnectionLost(self,connector,reason):
 print 'Lost connection: %s'%reason.getErrorMessage()
 reactor.stop()
 def clientConnectionFailed(self,connector,reason):
 print 'Connection failed: %s'%reason.getErrorMessage()
 reactor.stop()
 
reactor.connectTCP('localhost',1234,BasicClientFactory())
reactor.run()

客户端提取出来自Server的指令，当提取出Sync指令时，则将sourceDir目录清空，然后根据后续的指令，跟Server的文件夹进行同步。

客户端运行结果如下：

需要注意的地方：
Client写入文件时，需要以二进制的方式打开文件，否则，在传输二进制文件时可能出现错误或导致文件损坏。

经过测试，代码可以正常的运行，文件夹同步成功，文本文件、图像和其他类型的二进制文件均可正常传输。

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