python 網路編程——用戶端

標籤：

網路通訊的基本介面是socket，它擴充了作業系統的基本I/O到網路網路通訊。socket可以通過socket()函數來建立，通過connect()函數來串連。得到了socket，可以確定本地和遠程端點的IP地址和連接埠號碼。socket對不同的協議來說都是一種通用的介面，它可以處理TCP和UDP通訊。

建立socket需要兩步：建立socket對象、串連到遠程伺服器上

import socketprint "Creating socket"s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  #指明通訊類型和協議家族print "Done!"print "Connecting to remote host..."s.connect(("www.baidu.com", 80))print "Done"

運行結果

Creating socketDone!Connecting to remote host...Done

尋找連接埠號碼

通過協議名和連接埠名尋找連接埠號碼（unix系統可以在etc/services中找到對應的連接埠號碼）

import socketprint "Creating socket"s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)print "Done!"print "Looking up port number..."port = socket.getservbyname("http", "tcp")print portprint "done!"print "Connecting to remote host..."s.connect(("www.baidu.com", port))print "Done!!"

運行結果

Creating socketDone!Looking up port number...80done!Connecting to remote host...Done!!

從socket獲得資訊

import socketprint "Creating socket"s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)print "Done!"print "Looking up port number..."port = socket.getservbyname("http", "tcp")print portprint "done!"print "Connecting to remote host..."s.connect(("www.baidu.com", port))print "Done!!"print "Connected from", s.getsockname()  #獲得本地機器的ip和連接埠號碼（連接埠號碼由作業系統隨機分配，每次都不一樣）print "Connected to", s.getpeername()    #獲得串連機器的ip和連接埠號碼

一次運行結果

Creating socketDone!Looking up port number...80done!Connecting to remote host...Done!!Connected from (‘192.168.209.129‘, 56245)Connected to (‘220.181.112.244‘, 80)

利用socket通訊

socket對象：send()、sendto()、recv()、recvfrom()

檔案類對象：read()、write()、readline()

處理錯誤

import socket, syshost = sys.argv[1]textport = sys.argv[2]filename = sys.argv[3]try:    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)except socket.error, e:    print "Strange error creating socket: %s" % e    sys.exit(1)try:    port = int(textport)except ValueError:    try:        port = socket.getservbyname(textport, ‘tcp‘)    except socket.error, e:        print "Couldn‘t find your port: %s" % e        sys.exit(1)try:    s.connect((host, port))except socket.gaierror, e:    print "Address-related error connecting to server: %s" %e    sys.exit(1)except socket.error, e:    print "Connection error: %s" %e    sys.exit(1)try:    s.sendall("GET %s HTTP/1.0\r\n\r\n" % filename)except socket.error, e:    print "Error sending data: %s" %e    sys.exit(1)print "---------------------------------------"while 1:    try:        buf = s.recv(2048)    except socket.error, e:        print "========Error receving data: %s=======" %e        sys.exit(1)    if not len(buf):        break    sys.stdout.write(buf)print "---------------------------------------"

改進

#coding: utf-8import socketimport sysimport timehost = sys.argv[1]textport = sys.argv[2]filename = sys.argv[3]try:    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)except socket.error, e:    print "Strange error creating socket: %s" % e    sys.exit(1)try:    port = int(textport)except ValueError:    print "ValueError"    try:        port = socket.getservbyname(textport, ‘tcp‘)    except socket.error, e:        print "Couldn‘t find your port: %s" % e        sys.exit(1)try:    s.connect((host, port))except socket.gaierror, e:   #主機名稱不對    print "Address-related error connecting to server: %s" %e    sys.exit(1)except socket.error, e:      #串連遠程主機有問題    print "Connection error: %s" %e    sys.exit(1)print "Sleepping........."time.sleep(10)print "Continuing."try:    s.sendall("GET %s HTTP/1.0\r\n\r\n" % filename)except socket.error, e:    print "Error sending data: %s" % e    sys.exit(1)try:     s.shutdown(1)except socket.error, e:    print "Error sending data (detected by shutdown):%s" % e    sys.exit(1)    print "---------------------------------------"while 1:    try:        buf = s.recv(2048)        print "try"    except socket.error, e:        print "========Error receving data: %s=======" %e        sys.exit(1)    if not len(buf):  #接受的為空白        print "breaK"        break    sys.stdout.write(buf)print "---------------------------------------"

 

python 網路編程——用戶端