如何使用Python 2.7通过HTTP使用多线程下载文件(异步下载) [英] How to download a file over HTTP with multi-thread (asynchronous download) using Python 2.7

问题描述

我有一个文件要下载(从json中提取下载路径，例如:http://testsite/abc.zip).

我需要执行帮助，所有5个线程都应将abc.zip文件下载到输出目录，并且下载必须为异步或并发. /p>

当前使用以下代码，它确实可以下载文件5次，但可以一次下载一个(同步).

我想要的是同时下载.

def dldr(file=file_url, outputdir=out1):
    local_fn = str(uuid.uuid4())
    if not os.path.exists(outputdir):
        os.makedirs(outputdir)
    s = datetime.now()
    urllib.urlretrieve(file, outputdir + os.sep + local_fn)
    e = datetime.now()
    time_diff = e - s
    logger(out1, local_fn, time_diff)

for i in range(1, 6):
    t = threading.Thread(target=dldr())
    t.start()

我已阅读具有多个连接的请求，它很有帮助，但没有解决问题的要求.

解决方案

我将线程模块用于下载线程:
也可以请求，但是您可以自己将其更改为urllib.

import threading
import requests

def download(link, filelocation):
    r = requests.get(link, stream=True)
    with open(filelocation, 'wb') as f:
        for chunk in r.iter_content(1024):
            if chunk:
                f.write(chunk)

def createNewDownloadThread(link, filelocation):
    download_thread = threading.Thread(target=download, args=(link,filelocation))
    download_thread.start()

for i in range(0,5):
    file = "C:\\test" + str(i) + ".png"
    print file
    createNewDownloadThread("http://stackoverflow.com/users/flair/2374517.png", file)

I have a file to download (download path extracted from json. eg: http://testsite/abc.zip).

I need a help to perform, all the 5 threads should download the abc.zip file to the output directory and the download has to be Asynchronous or concurrent.

Currently with the below code it does download the file 5 times but it downloads one by one (Synchronous).

What I want is, the download to be simultaneous.

def dldr(file=file_url, outputdir=out1):
    local_fn = str(uuid.uuid4())
    if not os.path.exists(outputdir):
        os.makedirs(outputdir)
    s = datetime.now()
    urllib.urlretrieve(file, outputdir + os.sep + local_fn)
    e = datetime.now()
    time_diff = e - s
    logger(out1, local_fn, time_diff)

for i in range(1, 6):
    t = threading.Thread(target=dldr())
    t.start()

I have read Requests with multiple connections post and it's helpful, but doesn't address the requirement of the question asked.

解决方案

I use threading module for download threads:
Also requests, but you can change that to urllib by yourself.

import threading
import requests

def download(link, filelocation):
    r = requests.get(link, stream=True)
    with open(filelocation, 'wb') as f:
        for chunk in r.iter_content(1024):
            if chunk:
                f.write(chunk)

def createNewDownloadThread(link, filelocation):
    download_thread = threading.Thread(target=download, args=(link,filelocation))
    download_thread.start()

for i in range(0,5):
    file = "C:\\test" + str(i) + ".png"
    print file
    createNewDownloadThread("http://stackoverflow.com/users/flair/2374517.png", file)

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