ftp上传下载文件

客户端client：

 import os
 import json
 import socket
 import struct

 sk = socket.socket()
 sk.connect(('127.0.0.1',8090))

 buffer = 1024

 head = {'filepath':r'/Users/mango/Downloads/试题/07 python fullstack s9day9 第一次考试试题讲解',
         'filename':r'07 python fullstack s9day9 第一次考试试题讲解.mp4',
         'filesize':None}        #报头
 file_path = os.path.join(head['filepath'],head['filename'])      #文件路径
 filesize = os.path.getsize(file_path)              #文件大小
 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)           #计算报头的bytes有多长
 struct_len = struct.pack('i',head_len)      #打包成固定的4个字节
 sk.send(struct_len)        #发送长度
 sk.send(bytes_head)      #发送报头
 with open(file_path,'rb')as f:    #打开文件
     while filesize:
         if filesize >= buffer:
             content = f.read(buffer)
             filesize -= buffer
             sk.send(content)
         else:
             f.read(filesize)
             filesize -= buffer
             sk.send(content)
 sk.close()#                            

服务端server：

 import socket
 import struct
 import json                                           

 sk = socket.socket()
 sk.bind(('127.0.0.1',8090))
 sk.listen()
 buffer = 1024
 conn,addr = sk.accept()                               

 head_len = conn.recv(4)
 head_len = struct.unpack('i',head_len)[0]
 json_head = conn.recv(head_len).decode('utf-8')
 head = json.loads(json_head)   # 报头
 filesize = head['filesize']
 with open(head['filename'],'wb')as f:
     while filesize:
         if filesize >= buffer:
             content = conn.recv(buffer)
             f.write(content)
             filesize -= buffer
         else:
             content = conn.recv(filesize)
             f.write(content)
             break
 conn.close()
 sk.close()