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
• 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

1. 黏包现象 发送的两条数据粘在一起了
2. 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
3. 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:
4. 默写 黏包协议
5. 上传大文件(文件\视频\图片)
6. 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
7. 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()