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python 解决粘包现象(struct模块)

时间:2018-08-17 18:13:45      阅读:328      评论:0      收藏:0      [点我收藏+]

一. struct模块

   该模块可以把一个类型,转换为固定长度的bytes

import struct
lst  = [1,2,4,3,5,]
lst1  = [1,2,4,3,5,7,8,9,]
a = struct.pack(i,len(lst))#将列表的长度转化为固定的4字节
b = struct.pack(i,len(lst1))
print(a,len(a))
print(b,len(b))
技术分享图片

  符号对应的类型以及转换之后的长度表 : 

技术分享图片

  struct模块实现大文件传输 :

#server端
import socket
import struct
import json
import os

sk = socket.socket()
sk.bind((127.0.0.1,8989))
sk.listen()
conn,addr = sk.accept()

len_dic = struct.unpack(i,conn.recv(4))[0]#unpack解包接受的是元组类型,索引为0是字典的长度
str_dic = conn.recv(len_dic).decode(utf-8)#根据字典的长度将字典接收为字符串类型
dic = json.loads(str_dic)#将字符串类型的字典转换为字典(dict)
if dic[opt] == upload:
    up_load = D:\a\b\c\\ + os.path.basename(dic[filename])#路径拼接
    # up_load = os.path.join(‘D:\a\b\c\\‘,os.path.basename(dic[‘filename‘]))
    while dic[filesize] >0:
        read_size = conn.recv(2048)
        with open(os.path.abspath(up_load),mode=ab) as f1:
            f1.write(read_size)
            dic[filesize] -= len(read_size)

if dic[opt] == download:
    down_load = D:\a\b\c
    conn.send(json.dumps(os.listdir(down_load)).encode(utf-8))
    while 1:
        s = conn.recv(2048).decode(utf-8)
        file = os.path.abspath(down_load+/+s)
        print(file)
        if os.path.isdir(file):
            dic1 = {tybe:dir}
            len_dic1 = struct.pack(i,len(json.dumps(dic1)))
            conn.send(len_dic1 + json.dumps(dic1).encode(utf-8))
            conn.send(json.dumps(os.listdir(file)).encode(utf-8))
            down_load = os.path.abspath(file)
            continue
        elif os.path.isfile(file):
            dic2 = {tybe:fil,down_size:os.path.getsize(file)}
            len_dic2 = struct.pack(i,len(json.dumps(dic2)))
            conn.send(len_dic2 + json.dumps(dic2).encode(utf-8))
            with open(file,mode=rb) as f:
                down_size = os.path.getsize(file)
                while down_size:
                    a = f.read(2048)
                    print(a)###########
                    conn.send(a)
                    down_size -= len(a)
                break
#client端
import socket
import struct
import os
import json

sk = socket.socket()
sk.connect((127.0.0.1,8989))
def upload():
    dic = {opt:upload,filename:None,filesize:None}
    file = input(请输入一个想要上传的绝对路径: )
    dic[filename] = file
    dic[filesize] = os.path.getsize(file)
    str_dic = json.dumps(dic)
    len_dic = struct.pack(i,len(str_dic))#自动将字典的长度转换为4个bytes类型的长度
    sk.send(len_dic + str_dic.encode(utf-8))

    with open(dic[filename],mode=rb) as f:
        while dic[filesize] > 0:
            read_size = f.read(2048)
            sk.send(read_size)
            dic[filesize] -= len(read_size)

def download():
    dic = {opt:download,filename:None,filesize:None}
    sk.send(struct.pack(i,len(json.dumps(dic)))+json.dumps(dic).encode(utf-8))
    while 1:
        lst = json.loads(sk.recv(2048).decode(utf-8))
        for k, v in enumerate(lst, 1):
            print(k, v)
        file = input(请根据序号输入想要下载的文件: )
        sk.send(lst[int(file) - 1].encode(utf-8))
        len_dic = struct.unpack(i,sk.recv(4))[0]
        str_dic = sk.recv(len_dic).decode(utf-8)
        if json.loads(str_dic)[tybe] == dir:
            continue
        elif json.loads(str_dic)[tybe] == fil:
            down_file = D:\a\b\c\\+lst[int(file) - 1]
            while json.loads(str_dic)[down_size]:
                with open(down_file,mode=ab) as f:
                    down_ = sk.recv(2048)
                    f.write(down_)
                json.loads(str_dic)[down_size] -= len(down_)

if __name__ ==__main__:
    lst = [上传, 下载]
    def mai():
        for k,v in enumerate(lst,1):
            print(k,v)
        c = input(请按序号输入操作: )
        if c == 1:
            upload()
        if c == 2:
            download()
        else:
            print(输入错误!)
    mai()

 

python 解决粘包现象(struct模块)

原文:https://www.cnblogs.com/dong-/p/9494734.html

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