linux网络编程入门三步走

背景：每一个语言都会有入门的helloworld
内容：看完网络编程的基础知识，知道原来网络编程也有小练习
概述：Echo，Chat，Proxy

网上有专门的练习。不管是UNIX网络编程还是其他的书籍都会有相关的举例

Echo，chat，Proxy在这里统一再现Python的实现，主要是Python的比较简单，稍后也会补充一下PHP的swoole

Echo：

import os,sys,platformimport BaseHTTPServerfrom SocketServer import ThreadingMixInimport urllib,urllib2import shutilimport reimport timetry: from cStringIO import StringIOexcept ImportError: from StringIO import StringIOclass SimpleHTTPRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler): def do_GET(self):  f = StringIO()  f.write(self.path)  length = f.tell()  f.seek(0)  self.response(length)  if f:    shutil.copyfileobj(f,self.wfile)    f.close() def response(self,length):    self.send_response(200)    self.send_header("Content-type","text/html")    self.send_header("Content-Length",str(length))    self.end_headers()class ThreadingServer(ThreadingMixIn,BaseHTTPServer.HTTPServer):    passif __name__ =="__main__":    serveraddr = ("",int(sys.argv[1]))    print "LISTEN Port(%s)" % (int(sys.argv[1]))    srvr = ThreadingServer(serveraddr,SimpleHTTPRequestHandler)    srvr.serve_forever()

Chat:

import socket,selectdef broadcast_data(sock,message):    for socket in CONNECTION_LIST:        if socket != server_socket and socket !=sock:            try:                socket.send(message)            except:                socket.close()                CONNECTION_LIST.remove(socket)if __name__ =='__main__':    CONNECTION_LIST = []    RECV_BUFFER = 4096    HOST = '0.0.0.0'    PORT = 3446    server_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)    server_socket.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)    server_socket.bind((HOST,PORT))    server_socket.listen(10)    CONNECTION_LIST.append(server_socket)    print "Chat server started on port {}"+str(PORT)    while True:        read_sockets,write_sockets,error_sockets = select.select(CONNECTION_LIST,[],[])        for sock in read_sockets:            if sock ==server_socket:                sockfd,addr = server_socket.accept()                CONNECTION_LIST.append(sockfd)                print ("Client (%s,%s) connected" % addr)                broadcast_data(sockfd,"[%s:%s] entered room\n"% addr)            else:                try:                    data = sock.recv(RECV_BUFFER)                    if data:                        broadcast_data(sock,"\r"+'<'+str(sock.getpeername())+'>'+data)                except:                    broadcast_data(sock,"Client (%s,%s) is offline"% addr)                    print ("Client (%s,%s) is offline"% addr)                    sock.close()                    CONNECTION_LIST.remove(sock)                    continue    server_socket.close()

聊天的客户端也是一样的
Chat-Client:

import socket,select,string,sysdef prompt():    sys.stdout.write(" ")    sys.stdout.flush()if __name__=="__main__":    if(len(sys.argv)<3):        print "Usage: python chat_client.py host port"        sys.exit()    host = sys.argv[1]    port = int(sys.argv[2])    s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)    s.settimeout(2)    try:        s.connect((host,port))    except:        print ("Unable to connnect")        sys.exit()    print("Connected to remote host,Start send message")    prompt()    while True:        rlist = [sys.stdin,s]        read_list,write_list,error_list = select.select(rlist,[],[])        for sock in read_list:            if sock ==s:                data = sock.recv(4096)                if not data:                    print '\nDisconnected from chat server';                    sys.exit()                else:                    sys.stdout.write(data)                    prompt()            else:                msg = sys.stdin.readline()                s.send(msg)                prompt()

Proxy(好像当时码的时候有小错误，反正就是连接两边的服务器，都接收过来，然后各自在转发出去，来来回回，写晕了)

import sysimport socketimport threadingdef server_loop(local_host,local_port,remote_host,remote_port,receive_first):    server = socket.socket(socket.AF_INET,socket.SOCK_STREAM)    try:        server.bind(local_host,local_port)    except:        print ("[!!] Failed to listen on %s:%d"% (local_host,local_port))        print ("[!!] Check for other listening sockets or correct permissions")        sys.exit(0)    print ("[*] Listening on $s:%d"% (localhos_host,local_port))    server.listen(5)    while True:        client_socket.addr = server.accept()        print ("[==>] Received incoming connnection from %s:%d"% addr[0],addr[1])        proxy_thread = threading.Thread(target = proxy_handler,args =(client_socket,remote_host,remote_port,receive_first))        proxy_thread.start()def proxy_handler(client_socket,remote_host,remote_port,receive_first):    remote_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)    remote_socket.connect((remote_host,remote_port))    if receive_first:        remote_buffer = receive_from(remote_socket)        hexdump(remote_buffer)        remote_buffer = response_handler(remote_buffer)        remote_socket.send(local_buffer)        print("[==>] Sent to remote")        remote_buffer = receive_from(remote_socket)        if len(remote_buffer):            print("[<==] Sending %d bytes to local_host."%len(remote_buffer))            client.send(remote_buffer)        while True:            local_buffer = receive_from(client_socket)            if len(remote_buffer):                print ("[==>] Received %d bites from local_host" %len(local_buffer))                hexdump(local_buffer)                local_buffer = request_handler(local_buffer)                remote_socket.send(local_buffer)                print("[==>] Sent to remote")            remote_buffer = receive_from(remote_socket)            if len(remote_buffer):                print("[<== ] Received %d bytes from remote." % len(remote_buffer))                hexdump(remote_buffer)                    remote_buffer = response_handler(remote_buffer)                client.socket.send(remote_buffer)                print("[<==] Sent to Sent to local_host")            if not len(local_buffer) or not len(remote_buffer):                client_socket.close()                remote_socket.close()                print("[*] No more data.Closing connections")                 breakdef hexdump(src,length = 16):    result =[]    digits = 4 if isinstance(str,unicode) else 2    for i in xrange(0,len(src),length):        s = src[i:i+length]         hexa = b' '.join(["%0*x"%(digits,ord(x)) for x in s])        text = b''.join([x if 0x20 <= ord(0) <=0x7F else b'.' for x in s])        result.append(b'X %-*s %s'%(i,length*(digits + 1),hexa,text))    print(b'\n'.join(result))def receive_from(connection):    buffer = ''    connection.settimeout(2)    try:        while True:            data = connection.recv(4096)            if not data:                break            buffer +=data    except:        pass    return bufferdef request_handler(buffer):    return bufferdef response_handler(buffer):    return bufferdef main():    if len(sys.argv[1:])!=5:        print("Usage:python proxy.py [localhos_host] [local_port] [remote_host] [remote_port] [receice_first]")        print("Example:python proxy.py 127.0.0.1")        sys.exit(0)    local_host = sys.argv[1]    local_port = int(sys.argv[2])    remote_host = sys.argv[3]    remote_port = sys.argv[4]    receive_first = sys.argv[5]    if 'True' in receive_first:        receive_first = True    else:        receive_first = False        server_loop(local_host,local_port,remote_host,remote_port,receive_first)main()