Python 工具类实现大文件断点续传功能详解

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Sat Oct 23 13:54:39 2021
@author: huyi
"""
 
import os
import sys
 
import requests
 
 
 
def download(url, file_path):
    # 重试计数
    count = 0
    # 第一次请求是为了得到文件总大小
    r1 = requests.get(url, stream=True, verify=False)
    total_size = int(r1.headers['Content-Length'])
 
    # 判断本地文件是否存在，存在则读取文件数据大小
    if os.path.exists(file_path):
        temp_size = os.path.getsize(file_path)  # 本地已经下载的文件大小
    else:
        temp_size = 0
        
    # 对比一下，是不是还没下完
    print(temp_size)
    print(total_size)
    
    # 开始下载
    while count < 10:
        if count != 0:
            temp_size = os.path.getsize(file_path)
        # 文件大小一致，跳出循环
        if temp_size >= total_size:
            break
        count += 1
        print(
            "第[{}]次下载文件,已经下载数据大小:[{}],应下载数据大小:[{}]".format(
                count, temp_size, total_size))
        # 重新请求网址，加入新的请求头的
        # 核心部分，这个是请求下载时，从本地文件已经下载过的后面下载
        headers = {"Range": f"bytes={temp_size}-{total_size}"}
        # r = requests.get(url, stream=True, verify=False)
        r = requests.get(url, stream=True, verify=False, headers=headers)
 
        # "ab"表示追加形式写入文件
        with open(file_path, "ab") as f:
            if count != 1:
                f.seek(temp_size)
            for chunk in r.iter_content(chunk_size=1024 * 64):
                if chunk:
                    temp_size += len(chunk)
                    f.write(chunk)
                    f.flush()
                    ###这是下载实现进度显示####
                    done = int(50 * temp_size / total_size)
                    sys.stdout.write("\r[%s%s] %d%%" % (
                        '█' * done, ' ' * (50 - done), 100 * temp_size / total_size))
                    sys.stdout.flush()
        print("\n")
 
    return file_path

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Sat Oct 23 19:53:18 2021
@author: huyi
"""
 
from flask import Flask, request, make_response, send_from_directory
from gevent.pywsgi import WSGIServer
from gevent import monkey
 
# 将python标准的io方法，都替换成gevent中的同名方法，遇到io阻塞gevent自动进行协程切换
monkey.patch_all()
app = Flask(__name__)
 
@app.route("/download", methods=['GET'])
def download_file():
    get_data = request.args.to_dict()
    file_path = get_data.get('fileName')
 
    response = make_response(
        send_from_directory('/Users/huyi/Movies/Videos',file_path,as_attachment=True))
    response.headers["Content-Disposition"] = "attachment; filename={}".format(
        file_path.encode().decode('latin-1'))
    return response
 
if __name__ == '__main__':
    WSGIServer(('0.0.0.0', 8080), app).serve_forever()

download('http://localhost:8080/download?fileName=test.mp4', '/Users/huyi/Downloads/test.mp4')