2017.07.08 Python網絡編程之設定並獲取默認的套接字超時時間

1.設定並獲取默認的套接字超時時間：

# -*- coding: UTF-8 -*-
# 有時候你需要處理socket庫某些屬性的默認值，例如套接字超時時間
# !usr/bin/env python
# Python Network Programming Cookbook --Chapter -1
# This program is optimized for Python 2.7
# It may run on any other version with/without modifications

import socket

def test_socket_timeout():
    s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    print "默認套接字超時時間是：%s" %s.gettimeout()
    s.settimeout(100)
    print "現在套接字的超時時間是：%s" %s.gettimeout()

if __name__=='__main__':
    test_socket_timeout()

 

 運行程序遇到問題：No py.test runner found in selected interpreter

解決辦法：沒有找到py.test文件，給pycharm軟件管理員權限運行，然后安裝pytest包，pip install pytest

結果如下：

 

2.優雅的處理套接字錯誤：

# -*- coding: UTF-8 -*-
# 編寫幾個try-except代碼塊，每個代碼塊對應一種可能發生的錯誤
# !usr/bin/env python
# Python Network Programming Cookbook --Chapter -1
# This program is optimized for Python 2.7
# It may run on any other version with/without modifications


import socket
import sys
import argparse

def main( ):
    parser=argparse.ArgumentParser(description='socket Error Example')
    parser.add_argument('--host',action="store",dest="host",required=False)
    parser.add_argument('--port',action="store",dest="port",type=int,required=False)

    parser.add_argument('--file',action="store",dest="file",required=False)
    given_args=parser.parse_args()
    host=given_args.host
    port=given_args.port
    filename=given_args.file

    try:
        s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    except socket.error,e:
        print "發生錯誤當創建sock對象時:%s" %e
        sys.exit(1)


    try:
        print host,port
        s.connect((host,port))
    except socket.gaierror,e:
        print "連接服務器時地址釋放發生錯誤:%s" %e
        sys.exit(1)
    except socket.error,e:
        print "連接發生錯誤：%s" %e
        sys.exit(1)


    try:
        s.sendall("GET %s HTTP/1.0\r\n\r\n" %filename)
    except socket.error,e:
        print "發送數據時發生錯誤:%s" %e
        sys.exit(1)


    while 1:

        try:
            buf=s.recv(2048)
        except socket.error,e:
            print "接收數據發生錯誤：%s" %e
            sys.exit(1)
        if not len(buf):
            break

        sys.stdout.write(buf)


if __name__=='__main__':
    main()

 

 

3.修改套接字發送和接收的緩存區大小：

# -*- coding: UTF-8 -*-
# 默認的套接字緩沖區大小可能不夠用，此時可以將默認的套接字緩沖區大小改成一個更合適的值
# !usr/bin/env python
# Python Network Programming Cookbook --Chapter -1
# This program is optimized for Python 2.7
# It may run on any other version with/without modifications

import socket

SEND_BUF_SIZE=4096
RECV_BUF_SIZE=4096

def modify_buf_size():
    sock=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    
    bufsize=sock.getsockopt(socket.SOL_SOCKET,socket.SO_SNDBUF)
    print "緩沖區之前的大小:%d" %bufsize

    sock.setsockopt(socket.SOL_TCP,socket.TCP_NODELAY,1)
    sock.setsockopt(
        socket.SOL_SOCKET,
        socket.SO_SNDBUF,
        SEND_BUF_SIZE
    )
    sock.setsockopt(
        socket.SOL_SOCKET,
        socket.SO_RCVBUF,
        RECV_BUF_SIZE
    )

    bufsize=sock.getsockopt(socket.SOL_SOCKET,socket.SO_SNDBUF)
    print "修改后緩沖區大小是:%d" %bufsize

if __name__=='__main__':
    modify_buf_size()

 

 4.把套接字改為阻塞或非阻塞模式：默認情況下，TCP套接字處於阻塞模式中，也就是說，除非完成了某項操作，否則不會把控制權交還給程序

例如：調用connect()API后，連接操作會阻止程序繼續往下執行，直到連接成功為止

很多情況下，你並不想讓程序一直等待服務器響應或者有異常終止操作

 

# -*- coding: UTF-8 -*-
# 在Python中，套接字可以被設置為阻塞模式或非阻塞模式，
# 在非阻塞模式下，調用API后，例如send()或recv()方法如果遇到問題就會拋出異常，
# 但在阻塞模型下，遇到問題並不會阻止操作
# !usr/bin/env python
# Python Network Programming Cookbook --Chapter -1
# This program is optimized for Python 2.7
# It may run on any other version with/without modifications

import socket

def test_socket_modes():
    s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    s.setblocking(1)
    s.settimeout(0.5)
    s.bind(("127.0.0.1",0))

    socket_address=s.getsockname()
    print "服務器登錄socket:%s" %str(socket_address)

    while(1):
        s.listen(1)

if __name__=='__main__':
    test_socket_modes()