socket
网络上的两个程序通过一个双向的通信连接实现数据的交换，这个连接的一端称为一个socket（套接字）。
建立网络通信连接至少要一对socket。socket是对TCP/IP的封装
使用方法
步骤：
服务器端：
- 实例化类
- bind 绑定端口
- listen 监听端口
- accept 等待连接（阻塞）
sock, addr = server.accept()sock 是为客户端实例化的socket类， addr 是客户端的地址 - 与客户端交互：recv 接收（阻塞）、send 发送数据
- close 断开连接
客户端：
- 实例化类
- connect 连接端口
- 与服务器端交互：recv 接收（阻塞）、send 发送数据
- close 断开连接
只传输一条数据
server:
import socket
server = socket.socket()
server.bind(('localhost', 8001))
server.listen(3)
conn, addr = server.accept()
data = conn.recv(1024)
conn.send(b'Got')
print('recv:', data)
server.close()
client:
import socket
client = socket.socket()
client.connect(('localhost', 8001))
client.send(b'Hello')
data = client.recv(1024)
print('recv:', data)
client.close()
循环发送数据：
server:
import socket
server = socket.socket()
server.bind(('localhost', 8001))
server.listen(3)
while 1:
conn, addr = server.accept()
print('new connection:', addr)
while 1:
data = conn.recv(1024)
conn.send(b'Got')
if not data:
break
else:
print('recv:', data)client:
import socket
client = socket.socket()
client.connect(('localhost', 8001))
while 1:
data = input('>>>').strip()
if len(data) == 0:
# 注意不能发送内容为空，否则客户端会卡住
continue
if data == 'e':
break
else:
client.send(data.encode('utf-8'))
data = client.recv(1024)
print('recv:', data.decode())
client.close()模拟SSH
server:
import socket
import os
server = socket.socket()
server.bind(('localhost', 8001))
server.listen(3)
while 1:
try:
conn, addr = server.accept()
print('new connection:', addr)
while 1:
data = conn.recv(1024)
if not data:
break
else:
res = os.popen(data.decode()).read()
conn.send(res.encode())
except ConnectionResetError:
continue
client:
import socket
client = socket.socket()
client.connect(('localhost', 8001))
while 1:
data = input('>>>').strip()
if len(data) == 0:
# 注意不能发送内容为空，否则客户端会卡住
continue
if data == 'e':
break
else:
client.send(data.encode('utf-8'))
data = client.recv(1024)
print(data.decode())
client.close()
socket 黏包
传输大文件
server:
import socket
import os
import hashlib
server = socket.socket()
server.bind(('localhost', 8001))
server.listen(3)
while 1:
try:
conn, addr = server.accept()
print('new connection:', addr)
while 1:
cmd = conn.recv(1024).decode()
if not cmd:
print('lost client')
break
else:
file_name = cmd.split()[1]
if not os.path.isfile(file_name):
res = 'no such file'
else: # 存在可以传输的文件
m = hashlib.md5()
file_size = os.stat(file_name).st_size
print(file_size)
conn.send(str(file_size).encode())
conn.recv(1024)
with open(file_name, 'rb')as f:
for line in f:
conn.send(line)
m.update(line)
print('file md5:', m.hexdigest())
conn.send(m.hexdigest().encode())
except ConnectionResetError:
print('lost client')
continue
client:
import socket
import hashlib
client = socket.socket()
client.connect(('localhost', 8001))
while 1:
cmd = input('get filename: >>>').strip()
if len(cmd) == 0:
# 注意不能发送内容为空，否则客户端会卡住
continue
else:
client.send(cmd.encode('utf-8'))
file_name = cmd.split()[1]
received_size = 0
m = hashlib.md5()
total_size = client.recv(1024)
client.send(b'Get size')
f = open(file_name + '.new', 'wb')
while received_size < int(total_size.decode()):
size = int(total_size.decode()) - received_size
if size < 1024:
receive_size = size
else:
receive_size = 1024
data = client.recv(receive_size)
received_size += len(data)
f.write(data)
m.update(data)
else:
f.close()
print(m.hexdigest())
server_md5 = client.recv(1024).decode()
if m.hexdigest() == server_md5:
print('file checked')
client.close()
有时结束连接之后再连接会显示端口占用，可以通过重用端口省去等待的时间：server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) (bind 端口之前进行设置)
socket server
创建socketserver的基本步骤：
- 创建一个请求处理类，继承 BaseRequestHandler 并且重写父类中的 handle()
- 实例化 TCPServer ，将 server IP 和请求处理类传给 TCPServer
- 调用
server.handle_request() #只处理一个请求server.serve_forever() #处理多个一个请求，永远执行 - server_close()
继承关系
class BaseServer:
class TCPServer(BaseServer):
class UDPServer(TCPServer):
class UnixStreamServer(TCPServer):
class UnixDatagramServer(UDPServer):
class ThreadingUDPServer(ThreadingMixIn, UDPServer): pass
class ThreadingTCPServer(ThreadingMixIn, TCPServer): pass使用方法
import socketserver
class MyTCPHandler(socketserver.BaseRequestHandler):
def handle(self):
# 处理和客户端所有的交互
pass
if __name__ == '__main__':
HOST, PORT = 'localhost', 8001
server = socketserver.TCPServer((HOST, PORT), MyTCPHandler)
server.serve_forever()
如果要设置允许地址重用：allow_reuse_address 是 TCPServer 和 UDPServer 的类变量，之后又被实例化的类继承了，由于实例化的类继承父类的同时已经开始 bind，所以只能在他继承父类之前修改父类的类变量
HOST, PORT = 'localhost', 8001
socketserver.TCPServer.allow_reuse_address = True
server = socketserver.TCPServer((HOST, PORT), MyTCPHandler) # 实例化 bind listen
server.serve_forever()socket server 多并发
多线程：ThreadingTCPServer
多进程：ForkingTCPServer -only in Linux
使用时只需在实例化类时继承其中一个：
HOST, PORT = 'localhost', 8001
socketserver.TCPServer.allow_reuse_address = True
server = socketserver.ThreadingTCPServer((HOST, PORT), MyTCPHandler) # 实例化 bind listen
server.serve_forever()