问使用多个并行线程以部分方式下载大型文件

EN

import asyncio
import concurrent.futures
import functools
import requests
import os


# WARNING:
# Here I'm pointing to a publicly available sample video.
# If you are planning on running this code, make sure the
# video is still available as it might change location or get deleted.
# If necessary, replace it with a URL you know is working.
URL = 'https://download.samplelib.com/mp4/sample-30s.mp4'
OUTPUT = 'video.mp4'


async def get_size(url):
    response = requests.head(url)
    size = int(response.headers['Content-Length'])
    return size


def download_range(url, start, end, output):
    headers = {'Range': f'bytes={start}-{end}'}
    response = requests.get(url, headers=headers)

    with open(output, 'wb') as f:
        for part in response.iter_content(1024):
            f.write(part)


async def download(run, loop, url, output, chunk_size=1000000):
    file_size = await get_size(url)
    chunks = range(0, file_size, chunk_size)

    tasks = [
        run(
            download_range,
            url,
            start,
            start + chunk_size - 1,
            f'{output}.part{i}',
        )
        for i, start in enumerate(chunks)
    ]

    await asyncio.wait(tasks)

    with open(output, 'wb') as o:
        for i in range(len(chunks)):
            chunk_path = f'{output}.part{i}'

            with open(chunk_path, 'rb') as s:
                o.write(s.read())

            os.remove(chunk_path)


if __name__ == '__main__':
    executor = concurrent.futures.ThreadPoolExecutor(max_workers=3)
    loop = asyncio.new_event_loop()
    run = functools.partial(loop.run_in_executor, executor)

    asyncio.set_event_loop(loop)

    try:
        loop.run_until_complete(
            download(run, loop, URL, OUTPUT)
        )
    finally:
        loop.close()

import grequests

URL = 'https://cdimage.debian.org/debian-cd/current/amd64/iso-cd/debian-10.1.0-amd64-netinst.iso'
CHUNK_SIZE = 104857600  # 100 MB
HEADERS = []

_start, _stop = 0, 0
for x in range(4):  # file size is > 300MB, so we download in 4 parts. 
    _start = _stop
    _stop = 104857600 * (x + 1)
    HEADERS.append({"Range": "bytes=%s-%s" % (_start, _stop)})


rs = (grequests.get(URL, headers=h) for h in HEADERS)
downloads = grequests.map(rs)

with open('/tmp/debian-10.1.0-amd64-netinst.iso', 'ab') as f:
    for download in downloads:
        print(download.status_code)
        f.write(download.content)

from pySmartDL import SmartDL
obj = SmartDL(url, destination)
obj.start()

obj = SmartDL(url, dest,progress_bar=False)
obj.start(blocking=False)
while not obj.isFinished():
    download_precentage = round(obj.get_progress()*100,2)
    time.sleep(0.2)
    print(download_precentage)

obj = SmartDL(url, destination,threads=7) #by default thread = 5
obj.start()