网络上传输的数据都叫数据包，包里的数据都叫报文

报文里不只有数据，还有ip地址mac地址端口号等，存在报头里

 自己定制报文:比如文件名字、大小、类型、路径等

 

head = {'filename':'test','filesize':409600}

# 报头的长度　　　　#先接收4个字节

#send(head)　　　　#根据4个字节获取报头

#send(file)　　　　　#从报头获取filesize，然后根据filesize接收文件

#DDF协议

 

网络传输过程中处处有协议，协议就是一堆报头和报文，协议的解析过程不需要关心

协议本质上就是一种约定

 

SEVER:

import socket
import struct
import json

sk = socket.socket()
sk.bind(('127.0.0.1',8090))
sk.listen()
buffer = 1024
conn, addr = sk.accept()
pack_len = conn.recv(4)
head_len = struct.unpack('i',pack_len)[0]
json_head = conn.recv(head_len).decode('utf-8')
head = json.loads(json_head)
filesize = head['filesize']

with open(head['filename'],'wb') as f:
    while filesize:
        if filesize >= buffer:
            cont = conn.recv(buffer)
            f.write(cont)
            filesize -= buffer
        else:
            cont = conn.recv(filesize)
            f.write(cont)
            break

conn.close()
sk.close()

CLIENT:

import socket
import os
import struct
import json

buffer = 1024
sk = socket.socket()
sk.connect(('127.0.0.1',8090))
filepath = input('请输入文件路径：')
filename = input('请输入文件名')
head = {'filename':filename,'filepath':filepath,'filesize':None}
file_path = os.path.join(head['filepath'],head['filename'])
filesize = os.path.getsize(file_path)
head['filesize'] = filesize
json_head = json.dumps(head)    #字典转字符串
bytes_head = json_head.encode('utf-8')  #字符串转bytes
head_len = len(bytes_head)
pack_len = struct.pack('i',head_len)
sk.send(pack_len)
sk.send(bytes_head)

with open(file_path,'rb') as f:
    while filesize:
        if filesize>= buffer:
            cont = f.read(buffer)
            sk.send(cont)
            filesize -= buffer
        else:
            cont = f.read(filesize)
            sk.send(cont)
            break


sk.close()