day32 - sturct功能的使用，实现一个文件下载或上传

import struct
import json
import socket

socket_obj = socket.socket()
socket_obj.bind(('localhost', 8000))
socket_obj.listen(1024)
connection, address = socket_obj.accept()

# 先固定接收4字节
struct_from_client = connection.recv(4)
# 解包得到二进制字典长度
bytes_len = struct.unpack('i', struct_from_client)[0]
# 根据长度接收二进制字典
dic_str = connection.recv(bytes_len).decode('utf8')
dic_header = json.loads(dic_str)

# 二进制追加写入的方式
with open(dic_header['filename'], 'ab') as f:
    file_size = dic_header['file_size']
    buffer_len = dic_header['buffer_len']
    while file_size:
        if file_size < buffer_len:
            data_from_client = connection.recv(file_size)
            f.write(data_from_client)
            break
        data_from_client = connection.recv(buffer_len)
        f.write(data_from_client)
        file_size -= buffer_len

connection.close()
socket_obj.close()

import struct
import json
import socket
import os

socket_obj = socket.socket()
socket_obj.connect(('localhost', 8000))
dic_header = {
    'filename': 'linux.mp4',
    'file_dir': r'D:/',
    'file_size': '',
    'buffer_len': 256   # 每次接收多少字节
}

file_path = os.path.join(dic_header['file_dir'], dic_header['filename'])
# 文件大小
file_size = os.path.getsize(file_path)
dic_header['file_size'] = file_size
dic_json = json.dumps(dic_header)
# 获取二进制字典
dic_bytes = bytes(dic_json, encoding='utf8')
# 获取二进制字典长度
dic_len = len(dic_bytes)
# 将二进制字典的长度生成一个固定4字节长度的bytes
struct_to_server = struct.pack('i', dic_len)
# 发给另一端
# 另一端固定 recv(4)，再 unpack，得到二进制字典长度
socket_obj.send(struct_to_server)
# 另一端 recv(二进制字典长度)，将获得 bytes 字典
socket_obj.send(dic_bytes)

with open(file_path, 'rb') as f:
    buffer_len = dic_header['buffer_len']
    while file_size:
        if file_size < buffer_len:
            data_to_server = f.read(file_size)
            socket_obj.send(data_to_server)
            break
        data_to_server = f.read(buffer_len)
        socket_obj.send(data_to_server)
        file_size -= buffer_len

socket_obj.close()