socket加入循环和粘包问题
socket
socket加入通信循环
客户端
import socket
soc = socket.socket()
soc.connect(('127.0.0.1', 8080))
while True:
inp = input('请输入要发送的信息>>>')
soc.send(inp.encode('utf-8'))
服务端
import socket
soc = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
soc.bind(('127.0.0.1', 8080))
soc.listen(5)
conn, addr = soc.accept()
while True:
try:
data = conn.recv(1024)
print(data)
except Exception:
conn.close()
break
soc.close()
socket加入连接循环
客户端
import socket
soc = socket.socket()
soc.connect(('127.0.0.1', 8080))
while True:
inp = input('请输入要发送的消息>>>')
soc.send(inp.encode('utf-8'))
服务端
import socket
soc = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
soc.bind(('127.0.0.1', 8080))
soc.listen(5)
while True:
print('等待客户端连接...')
conn, addr = soc.accept()
print(f'客户端{addr}已连接上了')
while True:
try:
data = conn.recv(1024)
print(data)
except Exception:
break
conn.close()
soc.close()
ssh
ssh是远程执行命令
subprocess是执行系统命令的模块
import subprocess
# 执行系统dir命令,把执行的正确结果放到管道中
obj = subprocess.Popen('dir',shell=True,stdout=subprocess.PIPE)
# 拿到正确结果的管道,读出里面的内容
content = obj.stdout.read()
# 因为windows是用gbk编码的,所以要用gbk解码
print(str(content,encoding='gbk'))
粘包问题
粘包现象
客户端
import socket
soc = socket.socket()
soc.connect(('127.0.0.1', 8080))
while True:
inp = input('请输入要发送的消息>>>')
soc.send(b'a')
soc.send(b'b')
soc.send(b'c')
服务端
import socket
soc = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
soc.bind(('127.0.0.1', 8080))
soc.listen(5)
while True:
print('等待客户端连接...')
conn, addr = soc.accept()
print(f'客户端{addr}已连接上了')
while True:
try:
data1 = conn.recv(1024)
print(data1)
data2 = conn.recv(1024)
print(data2)
data3 = conn,recv(1024)
print(data3)
except Exception:
break
conn.close()
soc.close()
客户端发送a、b、c的消息时,服务端有时候会接收到好几个值,而不是单个的a、b、c,这个就是粘包问题。
注意:只有TCP有粘包现象,UDP永远不会粘包
因为TCP协议是基于数据流的,所以收发的消息是不能为空的;但是UDP协议是基于数据报的,即使发送了空内容,UDP协议也会封装上消息头,因此也不会是空内容。
解决粘包问题的方法
给我们要发送的消息加上自定义长度报头,报头中包含我们要发送消息的长度,接收消息的时候,先从读取固定长度的报头,然后再读取真实的长度。
客户端
import json
import socket
import struct
client = socket.socket()
client.connect(('127.0.0.1', 8080))
while True:
content = input('开始接收信息>>>')
head_len = struct.unpack('i', client.recv(4))[0]
dic = json.loads(client.recv(head_len))
size_len = dic['size']
name = dic['name']
count = 0
data = b''
with open(name, 'wb') as fw:
while count < size_len:
if size_len < 1024:
data_temp = client.recv(size_len)
else:
if size_len - count >= 1024:
data_temp = client.recv(1024)
else:
data_temp = client.recv(size_len - count)
data = data_temp
count += len(data_temp)
f.write(data)
print('接收完成')
client.close()
服务端
import os
import json
import socket
import struct
server = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
server.bind(('127.0.0.1', 8080))
server.listen(5)
while True:
conn, addr = server.accept()
while True:
dic = {'size': os.path.getsize('run.py'), 'name': 'new_run.py'}
dic_bytes = bytes(json.dumps(dic), 'utf-8')
dic_bytes_len = len(dic)
head = struct.pack('i', dic_bytes_len)
conn.send(head)
conn.send(dic_bytes)
with open('run.py', 'rb') as fr:
for line in fr:
conn.send(line)
conn.close()
server.close()