linux中shell實現socket編程簡單例子

說到socket，學過網路基礎的人都聽過，他是TCP/IP的抽象，他是網路世界的入口，它無處不在。

學會了socket編程，就意味著能夠更深層次的控制你的流量，之後再看python的urllib*或php的curl，簡直就是小兒科！

I. 一些名詞

Address Family

地址類型，協議族，可能是以下

socket.AF_INET ---> IPv4 addresses.
socket.AF_INET6 ---> IPv6 addresses.
socket.AF_UNIX ---> Unix domain sockets (例如 /var/run/mysqld/mysqld.sock is an example).
socket.AF_IPX ---> IPX addresses.
Socktype

sock類型

socket.SOCK_STREAM ---> 流式socket , for TCP
socket.SOCK_DGRAM ---> 資料報式socket , for UDP

其他

參數	取值	值	說明
Address Family	AF_INET	2	IPv4
	AF_INET6	23	IPv6
	AF_UNSPEC	0	協議無關
Protocol Numbers 協議號	IPPROTO_IP	0	IP協議
	IPPROTO_IPV4	4	IPv4
	IPPROTO_IPV6	41	IPv6
	IPPROTO_UDP	17	UDP
	IPPROTO_TCP	6	TCP
Socktype sock類型	SOCK_STREAM	1	流
	SOCK_DGRAM	2	資料報
ai_flags	AI_PASSIVE	1	被動的，用於bind，通常用於server socket
	AI_CANONNAME	2	用於返回主機的正式名稱
	AI_NUMERICHOST	4	地址為數字串

II. 簡單的例子

來自官方文檔的例子，很基礎。

服務端

# Echo server program
import socket

HOST = '127.0.0.1'                 # Symbolic name meaning all available interfaces
PORT = 50007              # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1)
conn, addr = s.accept()
print 'Connected by', addr
while 1:
    data = conn.recv(1024)
    if not data: break
    conn.sendall(data)
conn.close()
用戶端

# Echo client program
import socket

HOST = 'localhost'    # The remote host
PORT = 50007              # The same port as used by the server
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
s.sendall('Hello, world')
data = s.recv(1024)
s.close()
print 'Received', repr(data)

III. 更複雜的例子

服務端

與之前不同的是，支援IPV6

# Echo server program
import socket
import sys

HOST = None               # Symbolic name meaning all available interfaces
PORT = 50007              # Arbitrary non-privileged port
s = None
for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                              socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
    af, socktype, proto, canonname, sa = res
    try:
        s = socket.socket(af, socktype, proto)
    except socket.error as msg:
        s = None
        continue
    try:
        s.bind(sa)
        s.listen(1)
    except socket.error as msg:
        s.close()
        s = None
        continue
    break
if s is None:
    print 'could not open socket'
    sys.exit(1)
conn, addr = s.accept()
print 'Connected by', addr
while 1:
    data = conn.recv(1024)
    if not data: break
    conn.send(data)
conn.close()

用戶端

# Echo client program
import socket
import sys

HOST = 'localhost'    # The remote host
PORT = 50007              # The same port as used by the server
s = None
for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
    af, socktype, proto, canonname, sa = res
    try:
        s = socket.socket(af, socktype, proto)
    except socket.error as msg:
        s = None
        continue
    try:
        s.connect(sa)
    except socket.error as msg:
        s.close()
        s = None
        continue
    break
if s is None:
    print 'could not open socket'
    sys.exit(1)
s.sendall('Hello, world')
data = s.recv(1024)
s.close()
print 'Received', repr(data)

上面我們提到了socket編程的基本形式，這一節我們加強服務端的效能！

#!/usr/bin/env python

import socket, threading

class ClientThread(threading.Thread):

    def __init__(self, ip, port, socket):
        threading.Thread.__init__(self)
        self.ip = ip
        self.port = port
        self.socket = socket
        print "[+] New thread started for "+ip+":"+str(port)

    def run(self):   
        print "Connection from : "+ip+":"+str(port)

        self.socket.send("\nWelcome to the server\n\n")

        data = "dummydata"

        while len(data):
            data = self.socket.recv(2048)
            print "Client sent : "+data
            self.socket.send("You sent me : "+data)

        print "Client disconnected..."

host = "0.0.0.0"
port = 9999

tcpsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

tcpsock.bind((host,port))
threads = []

while True:
    tcpsock.listen(4)
    print "\nListening for incoming connections..."
    (clientsock, (ip, port)) = tcpsock.accept()
    newthread = ClientThread(ip, port, clientsock)
    newthread.start()
    threads.append(newthread)

for t in threads:
    t.join()