Chapter 14 of python, Network Programming

I. socket module

There are two types of sockets: Server, client,

Create a socket and wait for the connection

Server:

import sockets = socket.socket()port = 1234host = socket.gethostname()print hosts.bind((host,port))s.listen(5)while True:    get,addr = s.accept()    print 'Got connection from',addr    get.send('Thank you for connecting')    get.close()

Client:

import sockets = socket.socket()host = socket.gethostname()port = 1234s.connect((host,port))print s.recv(1024)

>>>
Z5WRYRLDY59AL03
Got connection from ('2017. 27.174.175 ', 222)
Got connection from ('2017. 27.174.175 ', 222)
Got connection from ('2017. 27.174.175 ', 222)
Got connection from ('2017. 27.174.175 ', 222)

>>>================================== RESTART ==== ======================================
>>>
Thank you for connecting
>>>================================== RESTART ==== ======================================
>>>
Thank you for connecting
>>>================================== RESTART ==== ======================================
>>>
Thank you for connecting
>>>================================== RESTART ==== ======================================
>>>
Thank you for connecting

Ii. urllib and urllib2

You can access the file through the network, and use urllib for simple download using a URL. If you want to use http verification or urllib2 using cookies

1. Open a Remote File

From urllib import urlopen

Webpage = urlopen ("http://www.baidu.com ")

Urlopen method: close, read, readline, readlines

2. obtain remote files

Urlretrieve ('HTTP: // www.python.org ', 'c: \ python.html ')

By default, it is placed in a temporary location and cleared with urlcleanup

3. SocketServer

SocketServer is the basis of many server frameworks, such as BaseHTTPServer, SimpleHTTPServer, and CGIHTTPServer.

SocketSever contains four basic classes: 1 TCPServer for TCP socket stream, 2. UDPServer for UDP datagram 3. UnixStreamServer 4. UnixDatagramServer

Server:

from SocketServer import TCPServer,StreamRequestHandlerimport socketclass Handler(StreamRequestHandler):    def handle(self):        addr = self.request.getpeername()        print 'Got connection from',addr        self.wfile.write('Thank you for connecting!!!')host = socket.gethostname()server = TCPServer((host,1234),Handler)server.serve_forever()

>>>
Thank you for connecting !!!
>>>

Got connection from ('2017. 27.174.175 ', 222)

4. Multiple connections

Three methods: forking, threading, and asynchronous I/O)

Use SocketServer for forks and thread processing

from SocketServer import TCPServer,ForkingMixIn,StreamRequestHandlerimport socketclass Server(ForkingMixIn,TCPServer):passclass Handler(StreamRequestHandler):    def handle(self):        addr = self.request.getpeername()        print 'Got connection from',addr        self.wfile.write('Thank you for connecting ...')host = socket.gethostname()server = Server(('',1234),Handler)server.serve_forever()

Use select

import socket,selects = socket.socket()host = socket.gethostname()port = 3306print hosts.bind((host,port))s.listen(5)inputs = [s]while True:    rs,ws,es = select.select(inputs,[],[])    for r in rs:        if r is s:            c,addr = s.accept()            print 'Got connection form',addr            inputs.append(c)        else:            try:                data = r.recv(1024)                disconnected = not data                if data:                    r.send('yes!I can hear you!')            except socket.error:                disconnected = True            if disconnected:                print r.getpeername(),'disconnected'                inputs.remove(r)            else:                print data