老师我想问一下为什么下载会文件不存在
#coding=utf-8
import struct
from socket import *
filename = 'test.jpg'
server_ip = "192.168.56.1"
send_data = struct.pack('!H%dsbsb'%len(filename),1,filename.encode(),0,'octet'.encode(),0)
s= socket(AF_INET,SOCK_DGRAM)
s.sendto(send_data,(server_ip,69))
f= open(filename,'ab')
while True:
recv_data=s.recvfrom(1024)
print(recv_data)
caozuoma,ack_num=struct.unpack('!HH',recv_data[0][:4])
rand_port=recv_data[1][1]
if int(caozuoma)==5:
print("文字不存在")
break
print("操作码: %d ACK: %d,服务器随机端口: %d,数据长度: %d"%(caozuoma,ack_num,rand_port,len(recv_data)))
f.write(recv_data[0][4:])
if len(recv_data[0])<516:
break
ack_num =struct.pack("!HH",4,ack_num)
s.sendto(ack_num,(server_ip,rand_port))


