【代码】Python使用requests下载文件时获取下载进度与实时速度
正文
使用requests, multiprocessing, time等库，代码如下，提供的注释供参考：
from contextlib import closing
import requests, os
import time, multiprocessing
from multiprocessing import Process
# 通过多进程实现实时速度显示
def download(download_url, download_path, headers):
file_name = os.path.basename(download_path)
with closing(requests.get(download_url, timeout=10, verify=False, stream=True, headers=headers)) as response:
chunk_size = 1024 # 单次请求最大值
content_size = int(response.headers['content-length']) # 文件总大小
with multiprocessing.Manager() as mng: # 通过Manager向定时显示进程传递信息
mdict = mng.dict()
mdict['data_bytes'] = 0 # 当前下载字节数
mdict['exit'] = False # 进程是否继续
process = Process(target=cron, args=(file_name, content_size, mdict)) # 生成进程对象，执行显示函数
# 开始下载
process.start()
with open(download_path, "wb") as file:
for data in response.iter_content(chunk_size=chunk_size): # 每取满chunk_size字节即存储
file.write(data)
mdict['data_bytes'] += len(data)
# 下载完毕
mdict['exit'] = True
process.join(3) # 3秒超时时间，显示完全
process.terminate() # 超时时直接终止
def cron(file_name, content_size, mdict): # 显示任务函数
interval = 0.5 # 执行间隔
content_size_formated = format_bytes_num(content_size) # 文件总大小转换为恰当显示格式
data_bytes_prev = mdict['data_bytes'] # 计算字节增量所需
time_prev = time_now = time.time() # 初值
while True: # 显示循环
data_bytes = mdict['data_bytes'] # 当前下载字节数
# 速度计算
try: speed_num = (data_bytes - data_bytes_prev) / (time_now - time_prev)
except ZeroDivisionError: speed_num = 0
data_bytes_prev = data_bytes # 存储当前字节数作为下次计算的参照
time_prev = time_now # 存储当前时间作为下次计算的参照
# 显示
speed = format_bytes_num(speed_num)
data_bytes_formated = format_bytes_num(data_bytes)
persent = data_bytes / content_size * 100 # 当前下载百分比
done_block = '█' * int(persent // 2) # 共显示50块，故以2除百作五十，计为所下载的显示块数
print(f"\r {file_name} ----> [{done_block:50}] {persent:.2f}% {speed}/s {data_bytes_formated}/{content_size_formated}", end=" ")
# 收到信号时退出
if mdict['exit']: break
# 消磨剩余时间
time_now = time.time()
sleep_time = time_prev + interval - time_now
if sleep_time > 0:
time.sleep(sleep_time)
time_now = time.time() # 避免误差
def format_bytes_num(bytes_num): # 格式化为合适的数值大小与单位
i = 0
while bytes_num > 1024 and i < 9 - 1:
bytes_num /= 1024
i += 1
unit = ('B', 'kiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB')[i]
return "%.2f" % bytes_num + unit
输出类似于：
