python - socket - connection

2023-01-30 16:56:24

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

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