Python socket 函數 getaddrinfo

# -*- coding: cp936 -*-socket.getaddrinfo(host,  port, family=0, socktype=0, proto=0, flags=0)#根據給定的參數host/port，相應的轉換成一個包含用於建立socket對象的五元組，#參數host為網域名稱，以字串形式給出代表一個IPV4/IPV6地址或者None.#參數port如果字串形式就代表一個服務名，比如“http”"ftp""email"等，或者為數字，或者為None#參數family為地主族，可以為AF_INET  ，AF_INET6 ，AF_UNIX.#參數socketype可以為SOCK_STREAM(TCP)或者SOCK_DGRAM(UDP)#參數proto通常為0可以直接忽略#參數flags為AI_*的組合，比如AI_NUMERICHOST，它會影響函數的傳回值#附註：給參數host,port傳遞None時建立在C基礎，通過傳遞NULL。#該函數返回一個五元組(family, socktype, proto, canonname, sockaddr)，同時第五個參數sockaddr也是一個二元組(address, port)# Echo server programimport socketimport sysHOST = None               # Symbolic name meaning all available interfacesPORT = 50007              # Arbitrary non-privileged ports = Nonefor res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,                              socket.SOCK_STREAM, 0, socket.AI_PASSIVE):    af, socktype, proto, canonname, sa = res    try:        #根據getaddrinfo()的返回資訊初始化socket        s = socket.socket(af, socktype, proto)    except socket.error, err_msg:        print err_msg #回顯異常資訊        s = None        continue    try:        #sa是(host,port)的二元組        s.bind(sa)        #監聽用戶端請求        s.listen(1)    except socket.error, err_msg:        print err_msg        s.close()        s = None        continue    breakif s is None:    print 'could not open socket'    sys.exit(1)    conn, addr = s.accept()print 'Connected by', addrwhile 1:    data = conn.recv(1024)# 2）接受資料    if not data: break    conn.send(data)# 3）並返回2中接受到得資料conn.close()# Echo client programimport socketimport sysHOST = 'daring.cwi.nl'    # The remote hostPORT = 50007              # The same port as used by the servers = Nonefor res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):    af, socktype, proto, canonname, sa = res    try:        s = socket.socket(af, socktype, proto)    except socket.error, msg:        s = None        continue    try:        s.connect(sa)    except socket.error, msg:        s.close()        s = None        continue    breakif s is None:    print 'could not open socket'    sys.exit(1)    s.sendall('Hello, world')# 1）發送資料data = s.recv(1024)# 4）接受伺服器回顯的資料s.close()print 'Received', repr(data) #列印輸出