python socket connection

前面有了TCP server和TCP client。在这个文章中我们建立tcp连接并且进行数据的发送。

例子，经常用到的echo功能。TCP client连接到server， 向server发送message，server端收到消息打印，并将消息返回给client。

server端代码：

import socket
import sys

def start_tcp_server(ip, port):
    #create socket
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    
    server_address = (ip, port)
    #bind port
    print 'starting listen on ip %s, port %s'%server_address
    sock.bind(server_address)
    
    #starting listening, allow only one connection
    try:
        sock.listen(1)
    except socket.error, e:
        print "fail to listen on port %s"%e
        sys.exit(1)
        
    while True:
        print "waiting for connection"
        client,addr = sock.accept()
        print 'having a connection'
        data = client.recv(1024)
        print 'recving data:'  +  data
        
        print 'send data back'
        client.sendall(data)
        client.close()
        
if __name__ == '__main__':
    start_tcp_server('172.125.0.1', 12346)

　　

client端代码：

import socket
import sys

def start_tcp_client(ip, port):
    
    #server port and ip
    server_ip = ip
    servr_port = port
    
    tcp_client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    
    try:
        tcp_client.connect((server_ip, servr_port))
    except socket.error:
        print 'fail to setup socket connection'
    else:
        print 'sending..........'
        tcp_client.sendall("echo message")
        
        print 'reading...........'
        print tcp_client.recv(1024)
    tcp_client.close()


start_tcp_client('172.125.0.1', 12346)

　　

这里面用到了收发函数，其中缓存的大小已经指定或者采用默认值。

如何查看一个连接的缓存大小并且在必要的时候修改它。

socket.getsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF)

socket.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, size)

如果是接受方的缓存，参数名称为SO_RCVBUF.

socket.getsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF)

socket.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, size)

我们增加代码加入参数，使用argparser 模块

client:

import socket
import sys
import argparse
def start_tcp_client(ip, port):
    
    #server port and ip
    server_ip = ip
    servr_port = port
    
    tcp_client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    
    try:
        tcp_client.connect((server_ip, servr_port))
    except socket.error:
        print 'fail to setup socket connection'
    else:
        print 'sending..........'
        tcp_client.sendall("echo message")
        
        print 'reading...........'
        print tcp_client.recv(1024)
    tcp_client.close()


if __name__ == '__main__':
    arg = argparse.ArgumentParser(description='input port and ip')
    arg.add_argument('-i', help='input the ip address')
    arg.add_argument('-p', type=int, help='input the port')
    args = arg.parse_args()
    print 'ip : port ' + args.i +" " + str(args.p)
    start_tcp_client(args.i, args.p)

　　

server:

import socket
import sys
import argparse


def start_tcp_server(ip, port):
    #create socket
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    
    server_address = (ip, port)
    #bind port
    print 'starting listen on ip %s, port %s'%server_address
    sock.bind(server_address)
    
    #starting listening, allow only one connection
    try:
        sock.listen(1)
    except socket.error, e:
        print "fail to listen on port %s"%e
        sys.exit(1)
        
    while True:
        print "waiting for connection"
        client,addr = sock.accept()
        print 'having a connection'
        data = client.recv(1024)
        print 'recving data:'  +  data
        
        print 'send data back'
        client.sendall(data)
        client.close()
        
if __name__ == '__main__':
    arg = argparse.ArgumentParser(description='input port and ip')
    arg.add_argument('-i', help='input the ip address')
    arg.add_argument('-p', type=int, help='input the port')
    args = arg.parse_args()
    print 'ip : port ' + args.i +" " + str(args.p)
    start_tcp_server(args.i, args.p)

　

调用：

启动server：

# python socket_1_server.py -i 10.135.13.171 -p 12345
ip : port 10.135.13.171 12345
starting listen on ip 10.135.13.171, port 12345
waiting for connection

启动client：

# python socket_2_client.py -i 10.135.13.171 -p 12345
ip : port 10.135.13.171 12345
sending..........
reading...........
echo message

server侧打印：

having a connection
recving data:echo message
send data back
waiting for connectio