2019-04-10-day029-粘包处理
内容回顾
osi五层协议
- 不是真实存在的,只是抽象出来的模型
- 应用层
- 传输层 TCP/UDP
- TCP :全双工,可靠的,面向连接的,速度慢,对数据大小没有限制
- 建立连接 :三次握手 SYN ACK
- 断开连接 :四次挥手 FIN ACK
- UDP :不可靠,无连接的,速度快,对数据大小有限制
- TCP :全双工,可靠的,面向连接的,速度慢,对数据大小没有限制
- 网络层 arp(ip-->mac) rarp(mac-->ip)
- 数据链路层 arp(ip-->mac) rarp(mac-->ip)
- 物理层 网线
TCP/IP 也是抽象出来的模型
struct 模块
import struct
ret = struct.pack('i',112849)
print(ret)
ret2 = struct.unpack('i',ret)
print(ret2)
总结
- 黏包现象 发送的两条数据粘在一起了
- 成因 :
- 发送端粘 : 合包机制
- 接收端粘 : 接收不及时
- 数据与数据之间是无边界的流式传输
- 解决黏包现象
- 自定义协议
- struct模块
- 把任意长度的数字变成固定的4个字节
- 低级
- 先发送数据的长度
- 再发送数据
- 高级
- 先把所有想发送的数据信息放在字典里
- 发送字典的长度
- 发送字典
- 发送涉及的数据
##作业:
- struct模块
- 自定义协议
- 默写 黏包协议
- 上传大文件(文件\视频\图片)
- 和你的同桌调通 从你的计算机上传一个视频到你同桌的电脑上
- 进阶 : 带上登录
课上代码
登陆一
server:
import sys
import json
import socket
import hashlib
def get_md5(username,password):
md5 = hashlib.md5(username.encode('utf-8'))
md5.update(password.encode('utf-8'))
return md5.hexdigest()
def login(dic_msg):
print(dic_msg['user'], dic_msg['pwd'])
with open('userinfo', encoding='utf-8') as f:
for line in f:
user, pwd = line.strip().split('|')
if user == dic_msg['user'] and pwd == get_md5(dic_msg['user'], dic_msg['pwd']):
return {'opt':'login','result':True}
else:return {'opt':'login','result':False}
sk= socket.socket()
sk.bind(('127.0.0.1',9001))
sk.listen()
while True:
conn,addr = sk.accept()
msg = conn.recv(1024).decode('utf-8')
dic_msg = json.loads(msg)
if hasattr(sys.modules[__name__],dic_msg['operate']):
ret = getattr(sys.modules[__name__],dic_msg['operate'])(dic_msg)
content = json.dumps(ret).encode('utf-8')
conn.send(content)
conn.close()
sk.close()
Client
import json
import socket
username = input('用户名 :')
password = input('密 码 :')
sk = socket.socket()
sk.connect(('127.0.0.1',9001))
msg = {'operate':'login',
'user':username,
'pwd':password}
str_msg = json.dumps(msg)
sk.send(str_msg.encode('utf-8'))
content = sk.recv(1024)
str_content = content.decode('utf-8')
dic_content = json.loads(str_content)
if dic_content['result']:
print('登录成功')
else:
print('登录失败')
sk.close()
登陆二
Server
import sys
import json
import socket
import hashlib
def get_md5(username,password):
md5 = hashlib.md5(username.encode('utf-8'))
md5.update(password.encode('utf-8'))
return md5.hexdigest()
def login(dic_msg):
print(dic_msg['user'], dic_msg['pwd'])
with open('userinfo', encoding='utf-8') as f:
for line in f:
user, pwd = line.strip().split('|')
print(pwd,get_md5(dic_msg['user'], dic_msg['pwd']))
if user == dic_msg['user'] and pwd == get_md5(dic_msg['user'], dic_msg['pwd']):
return {'opt':'login','result':True}
else:return {'opt':'login','result':False}
sk= socket.socket()
sk.bind(('127.0.0.1',9001))
sk.listen()
while True:
conn,addr = sk.accept()
msg = conn.recv(1024).decode('utf-8')
dic_msg = json.loads(msg)
if hasattr(sys.modules[__name__],dic_msg['operate']):
ret = getattr(sys.modules[__name__],dic_msg['operate'])(dic_msg)
content = json.dumps(ret).encode('utf-8')
conn.send(content)
conn.close()
sk.close()
Client
import json
import socket
import hashlib
def get_md5(username,password):
md5 = hashlib.md5(username[::2].encode('utf-8'))
md5.update(password.encode('utf-8'))
return md5.hexdigest()
username = input('用户名 :')
password = input('密 码 :')
sk = socket.socket()
sk.connect(('127.0.0.1',9001))
msg = {'operate':'login',
'user':username,
'pwd':get_md5(username,password)}
str_msg = json.dumps(msg)
sk.send(str_msg.encode('utf-8'))
content = sk.recv(1024)
str_content = content.decode('utf-8')
dic_content = json.loads(str_content)
if dic_content['result']:
print('登录成功')
else:
print('登录失败')
sk.close()
黏包练习
Server
import struct
import socket
sk = socket.socket()
sk.bind(('127.0.0.1',9001))
sk.listen()
conn,addr = sk.accept()
num = conn.recv(4)
num = struct.unpack('i',num)[0]
file_name = conn.recv(num).decode('utf-8')
filesize = conn.recv(4)
filesize = struct.unpack('i',filesize)[0]
with open(file_name,'wb') as f:
content = conn.recv(filesize)
f.write(content)
conn.close()
sk.close()
Client
import os
import struct
import socket
sk = socket.socket()
sk.connect(('127.0.0.1',9001))
filepath = input('请输入文件路径 :')
filename = os.path.basename(filepath).encode('utf-8')
name_len = struct.pack('i',len(filename))
sk.send(name_len)
sk.send(filename)
filesize = os.path.getsize(filepath)
file_len = struct.pack('i',filesize)
sk.send(file_len)
with open(filepath,'rb') as f:
content = f.read()
sk.send(content)
sk.close()
# 先发送字典的长度
# 再发字典 {'filename':xxxx,'filesize':xxxxx}
# 再发文件内容
黏包现象
Server
import socket
sk = socket.socket()
sk.bind(('127.0.0.1',9001))
sk.listen()
conn,addr = sk.accept()
conn.send(b'0015hello,你好么')
conn.send(b'5world')
conn.close()
sk.close()
Client
import time
import socket
sk = socket.socket()
sk.connect(('127.0.0.1',9001))
time.sleep(0.1)
num= sk.recv(2).decode('utf-8')
num = int(num)
msg1 = sk.recv(num)
num= sk.recv(1).decode('utf-8')
num = int(num)
msg2 = sk.recv(num)
print(msg1,msg2)
sk.close()
黏包现象2
Server
import struct
import socket
sk = socket.socket()
sk.bind(('127.0.0.1',9001))
sk.listen()
conn,addr = sk.accept()
str_msg = 'hello,你好么'
byets_msg = str_msg.encode('utf-8')
num = len(byets_msg)
len_bytes = struct.pack('i',num)
conn.send(len_bytes)
conn.send(byets_msg)
conn.send(b'world')
conn.close()
sk.close()
Client
import time
import struct
import socket
sk = socket.socket()
sk.connect(('127.0.0.1',9001))
time.sleep(0.1)
num= sk.recv(4)
num = struct.unpack('i',num)[0]
msg2 = sk.recv(num)
print(msg2.decode('utf-8'))
print(sk.recv(1024))
sk.close()
黏包协议
Server
import json
import struct
import socket
sk = socket.socket()
sk.bind(('127.0.0.1',9001))
sk.listen()
conn,addr = sk.accept()
num = conn.recv(4)
num = struct.unpack('i',num)[0]
str_dic = conn.recv(num).decode('utf-8')
dic = json.loads(str_dic)
with open(dic['filename'],'wb') as f:
content = conn.recv(dic['filesize'])
f.write(content)
conn.close()
sk.close()
Client
import os
import json
import struct
import socket
sk = socket.socket()
sk.connect(('127.0.0.1',9001))
filepath = input('请输入文件路径 :')
filename = os.path.basename(filepath)
filesize = os.path.getsize(filepath)
dic = {'filename':filename,'filesize':filesize}
str_dic = json.dumps(dic)
bytes_dic = str_dic.encode('utf-8')
len_dic = len(bytes_dic)
bytes_len = struct.pack('i',len_dic)
sk.send(bytes_len)
sk.send(bytes_dic)
with open(filepath,'rb') as f:
content = f.read()
sk.send(content)
sk.close()
# 先发送字典的长度
# 再发字典 {'filename':xxxx,'filesize':xxxxx}
# 再发文件内容
一对多人聊天
Server
import json
import socket
sk = socket.socket(type=socket.SOCK_DGRAM)
sk.bind(('127.0.0.1',9001))
user_info = {
1234:('alex','\033[1;32m'),
5678:('宝元','\033[1;31m'),
}
while True:
msg,addr = sk.recvfrom(1024)
str_msg = msg.decode('utf-8')
dic_msg = json.loads(str_msg)
code = dic_msg['code']
content = dic_msg['msg']
print('%s%s : %s\033[0m'%(user_info[code][1],user_info[code][0],content))
ret = input('>>>').encode('utf-8')
sk.sendto(ret,addr)
sk.close()
ClientI
import json
import socket
sk = socket.socket(type=socket.SOCK_DGRAM)
addr = ('127.0.0.1',9001)
code = 5678
while True:
msg = input('>>>')
if msg.upper() == 'Q': break
send_msg = {'code':code,'msg':msg}
str_msg = json.dumps(send_msg)
sk.sendto(str_msg.encode('utf-8'),addr)
ret = sk.recv(1024).decode('utf-8')
if ret.upper() == 'Q': break
print(ret)
sk.close()
ClientII
import json
import socket
sk = socket.socket(type=socket.SOCK_DGRAM)
addr = ('127.0.0.1',9001)
code = 1234
while True:
msg = input('>>>')
if msg.upper() == 'Q':break
send_msg = {'code':code,'msg':msg}
str_msg = json.dumps(send_msg)
sk.sendto(str_msg.encode('utf-8'),addr)
ret = sk.recv(1024).decode('utf-8')
if ret.upper() == 'Q':break
print(ret)
sk.close()

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