如何使用Python通过HTTP下载文件？

Question

我有一个小工具,用于按计划从网站下载MP3,然后构建/更新播客XML文件,我显然已将其添加到iTunes.

创建/更新XML文件的文本处理是用Python编写的.我在Windows .bat文件中使用wget 来下载实际的MP3.我宁愿用Python编写整个实用程序.

我努力寻找一种方法来实际下载Python中的文件,因此我采用了wget.

那么,我如何使用Python下载文件？

Answer 1

还有一个,使用urlretrieve:

import urllib
urllib.urlretrieve ("http://www.example.com/songs/mp3.mp3", "mp3.mp3")

(对于Python 3+,使用'import urllib.request'和urllib.request.urlretrieve)

又一个,带有"进度条"

import urllib2

url = "http://download.thinkbroadband.com/10MB.zip"

file_name = url.split('/')[-1]
u = urllib2.urlopen(url)
f = open(file_name, 'wb')
meta = u.info()
file_size = int(meta.getheaders("Content-Length")[0])
print "Downloading: %s Bytes: %s" % (file_name, file_size)

file_size_dl = 0
block_sz = 8192
while True:
    buffer = u.read(block_sz)
    if not buffer:
        break

    file_size_dl += len(buffer)
    f.write(buffer)
    status = r"%10d  [%3.2f%%]" % (file_size_dl, file_size_dl * 100. / file_size)
    status = status + chr(8)*(len(status)+1)
    print status,

f.close()

Answer 2

在Python 2中,使用标准库附带的urllib2.

import urllib2
response = urllib2.urlopen('http://www.example.com/')
html = response.read()

这是使用库的最基本方法,减去任何错误处理.您还可以执行更复杂的操作,例如更改标题.文档可以在这里找到.

Answer 3

在2012年,使用python请求库

>>> import requests
>>> 
>>> url = "http://download.thinkbroadband.com/10MB.zip"
>>> r = requests.get(url)
>>> print len(r.content)
10485760

你可以跑去pip install requests搞定.

请求与备选方案相比具有许多优点,因为API更简单.如果您必须进行身份验证,则尤其如此.在这种情况下,urllib和urllib2非常不直观和痛苦.

2015年12月30日

人们对进度条表示钦佩.这很酷,当然.现在有几种现成的解决方案,包括tqdm:

from tqdm import tqdm
import requests

url = "http://download.thinkbroadband.com/10MB.zip"
response = requests.get(url, stream=True)

with open("10MB", "wb") as handle:
    for data in tqdm(response.iter_content()):
        handle.write(data)

这基本上是30个月前@kvance所描述的实现.

Answer 4

import urllib2
mp3file = urllib2.urlopen("http://www.example.com/songs/mp3.mp3")
with open('test.mp3','wb') as output:
  output.write(mp3file.read())

在wb中open('test.mp3','wb')打开一个文件(并清除所有现有文件)以二进制模式,所以你可以用它来代替刚才保存的文本数据.

Answer 5

Python 3

• urllib.request.urlopen

  import urllib.request
  response = urllib.request.urlopen('http://www.example.com/')
  html = response.read()
  

• urllib.request.urlretrieve

  import urllib.request
  urllib.request.urlretrieve('http://www.example.com/songs/mp3.mp3', 'mp3.mp3')
  

Python 2

• urllib2.urlopen(谢谢科里)

  import urllib2
  response = urllib2.urlopen('http://www.example.com/')
  html = response.read()
  

• urllib.urlretrieve(感谢PabloG)

  import urllib
  urllib.urlretrieve('http://www.example.com/songs/mp3.mp3', 'mp3.mp3')
  

Answer 6

使用wget模块:

import wget
wget.download('url')

Answer 7

Python 2/3的PabloG代码的改进版本:

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import ( division, absolute_import, print_function, unicode_literals )

import sys, os, tempfile, logging

if sys.version_info >= (3,):
    import urllib.request as urllib2
    import urllib.parse as urlparse
else:
    import urllib2
    import urlparse

def download_file(url, dest=None):
    """ 
    Download and save a file specified by url to dest directory,
    """
    u = urllib2.urlopen(url)

    scheme, netloc, path, query, fragment = urlparse.urlsplit(url)
    filename = os.path.basename(path)
    if not filename:
        filename = 'downloaded.file'
    if dest:
        filename = os.path.join(dest, filename)

    with open(filename, 'wb') as f:
        meta = u.info()
        meta_func = meta.getheaders if hasattr(meta, 'getheaders') else meta.get_all
        meta_length = meta_func("Content-Length")
        file_size = None
        if meta_length:
            file_size = int(meta_length[0])
        print("Downloading: {0} Bytes: {1}".format(url, file_size))

        file_size_dl = 0
        block_sz = 8192
        while True:
            buffer = u.read(block_sz)
            if not buffer:
                break

            file_size_dl += len(buffer)
            f.write(buffer)

            status = "{0:16}".format(file_size_dl)
            if file_size:
                status += "   [{0:6.2f}%]".format(file_size_dl * 100 / file_size)
            status += chr(13)
            print(status, end="")
        print()

    return filename

if __name__ == "__main__":  # Only run if this file is called directly
    print("Testing with 10MB download")
    url = "http://download.thinkbroadband.com/10MB.zip"
    filename = download_file(url)
    print(filename)

Answer 8

图书馆提供简单而Python 2 & Python 3兼容的方式six:

from six.moves import urllib
urllib.request.urlretrieve("http://www.example.com/songs/mp3.mp3", "mp3.mp3")

Answer 9

import os,requests
def download(url):
    get_response = requests.get(url,stream=True)
    file_name  = url.split("/")[-1]
    with open(file_name, 'wb') as f:
        for chunk in get_response.iter_content(chunk_size=1024):
            if chunk: # filter out keep-alive new chunks
                f.write(chunk)


download("https://example.com/example.jpg")

Answer 10

为此目的在纯Python中编写了wget库.从版本2.0 开始urlretrieve,它就具备了这些功能.

Answer 11

我同意Corey,urllib2比urllib更完整,如果你想做更复杂的事情,应该是使用的模块,但为了使答案更加完整,如果你只想要基础知识,urllib是一个更简单的模块:

import urllib
response = urllib.urlopen('http://www.example.com/sound.mp3')
mp3 = response.read()

会工作得很好.或者,如果您不想处理"响应"对象,可以直接调用read():

import urllib
mp3 = urllib.urlopen('http://www.example.com/sound.mp3').read()

Answer 12

以下是在python中下载文件最常用的调用:

1. urllib.urlretrieve ('url_to_file', file_name)

2. urllib2.urlopen('url_to_file')

3. requests.get(url)

4. wget.download('url', file_name)

注意:urlopen并且urlretrieve发现下载大文件(大小> 500 MB)时性能相对较差.requests.get将文件存储在内存中,直到下载完成.

Answer 13

您可以使用 python请求

import os
import requests


outfile = os.path.join(SAVE_DIR, file_name)
response = requests.get(URL, stream=True)
with open(outfile,'wb') as output:
  output.write(response.content)

你可以使用shutil

import os
import requests
import shutil
 
outfile = os.path.join(SAVE_DIR, file_name)
response = requests.get(url, stream = True)
with open(outfile, 'wb') as f:
  shutil.copyfileobj(response.content, f)

• 如果您从受限网址下载，请不要忘记在标头中包含访问令牌

Answer 14

您也可以通过urlretrieve获取进度反馈:

def report(blocknr, blocksize, size):
    current = blocknr*blocksize
    sys.stdout.write("\r{0:.2f}%".format(100.0*current/size))

def downloadFile(url):
    print "\n",url
    fname = url.split('/')[-1]
    print fname
    urllib.urlretrieve(url, fname, report)

Answer 15

如果安装了wget,则可以使用parallel_sync.

pip install parallel_sync

from parallel_sync import wget
urls = ['http://something.png', 'http://somthing.tar.gz', 'http://somthing.zip']
wget.download('/tmp', urls)
# or a single file:
wget.download('/tmp', urls[0], filenames='x.zip', extract=True)

Doc:https: //pythonhosted.org/parallel_sync/pages/examples.html

这非常强大.它可以并行下载文件,在失败时重试,甚至可以在远程机器上下载文件.

Answer 16

在python3中,您可以使用urllib3和shutil libraires.使用pip或pip3下载它们(取决于python3是否默认)

pip3 install urllib3 shutil

然后运行此代码

import urllib.request
import shutil

url = "http://www.somewebsite.com/something.pdf"
output_file = "save_this_name.pdf"
with urllib.request.urlopen(url) as response, open(output_file, 'wb') as out_file:
    shutil.copyfileobj(response, out_file)

请注意,您下载urllib3但urllib在代码中使用

Answer 17

5行内使用Python请求

import requests as req

remote_url = 'http://www.example.com/sound.mp3'
local_file_name = 'sound.mp3'

data = req.get(remote_url)

# Save file data to local copy
with open(local_file_name, 'wb')as file:
    file.write(data.content)

现在对远程文件的本地副本执行一些操作

Answer 18

我编写了以下代码，它可以在普通 Python 2 或 Python 3 中运行。

import sys
try:
    import urllib.request
    python3 = True
except ImportError:
    import urllib2
    python3 = False


def progress_callback_simple(downloaded,total):
    sys.stdout.write(
        "\r" +
        (len(str(total))-len(str(downloaded)))*" " + str(downloaded) + "/%d"%total +
        " [%3.2f%%]"%(100.0*float(downloaded)/float(total))
    )
    sys.stdout.flush()

def download(srcurl, dstfilepath, progress_callback=None, block_size=8192):
    def _download_helper(response, out_file, file_size):
        if progress_callback!=None: progress_callback(0,file_size)
        if block_size == None:
            buffer = response.read()
            out_file.write(buffer)

            if progress_callback!=None: progress_callback(file_size,file_size)
        else:
            file_size_dl = 0
            while True:
                buffer = response.read(block_size)
                if not buffer: break

                file_size_dl += len(buffer)
                out_file.write(buffer)

                if progress_callback!=None: progress_callback(file_size_dl,file_size)
    with open(dstfilepath,"wb") as out_file:
        if python3:
            with urllib.request.urlopen(srcurl) as response:
                file_size = int(response.getheader("Content-Length"))
                _download_helper(response,out_file,file_size)
        else:
            response = urllib2.urlopen(srcurl)
            meta = response.info()
            file_size = int(meta.getheaders("Content-Length")[0])
            _download_helper(response,out_file,file_size)

import traceback
try:
    download(
        "https://geometrian.com/data/programming/projects/glLib/glLib%20Reloaded%200.5.9/0.5.9.zip",
        "output.zip",
        progress_callback_simple
    )
except:
    traceback.print_exc()
    input()

笔记：

• 支持“进度条”回调。
• 从我的网站下载 4 MB 测试 .zip。

Answer 19

如果速度对你很重要，我对模块urllib和进行了一个小的性能测试wget，关于wget我尝试了一次状态栏和一次没有。我拿了三个不同的 500MB 文件来测试（不同的文件 - 以消除在后台进行一些缓存的可能性）。在 debian 机器上测试，使用 python2。

首先，这些是结果（它们在不同的运行中是相似的）：

$ python wget_test.py 
urlretrive_test : starting
urlretrive_test : 6.56
==============
wget_no_bar_test : starting
wget_no_bar_test : 7.20
==============
wget_with_bar_test : starting
100% [......................................................................] 541335552 / 541335552
wget_with_bar_test : 50.49
==============

我执行测试的方式是使用“配置文件”装饰器。这是完整的代码：

import wget
import urllib
import time
from functools import wraps

def profile(func):
    @wraps(func)
    def inner(*args):
        print func.__name__, ": starting"
        start = time.time()
        ret = func(*args)
        end = time.time()
        print func.__name__, ": {:.2f}".format(end - start)
        return ret
    return inner

url1 = 'http://host.com/500a.iso'
url2 = 'http://host.com/500b.iso'
url3 = 'http://host.com/500c.iso'

def do_nothing(*args):
    pass

@profile
def urlretrive_test(url):
    return urllib.urlretrieve(url)

@profile
def wget_no_bar_test(url):
    return wget.download(url, out='/tmp/', bar=do_nothing)

@profile
def wget_with_bar_test(url):
    return wget.download(url, out='/tmp/')

urlretrive_test(url1)
print '=============='
time.sleep(1)

wget_no_bar_test(url2)
print '=============='
time.sleep(1)

wget_with_bar_test(url3)
print '=============='
time.sleep(1)

urllib 似乎是最快的

Answer 20

仅出于完整性考虑，也可以使用该subprocess软件包调用任何程序来检索文件。专用于检索文件的程序比Python函数（如）强大urlretrieve。例如，wget可以递归下载目录（-R），可以处理FTP，重定向，HTTP代理，可以避免重新下载现有文件（-nc），并且aria2可以进行多连接下载，从而有可能加快下载速度。

import subprocess
subprocess.check_output(['wget', '-O', 'example_output_file.html', 'https://example.com'])

在Jupyter Notebook中，还可以使用以下!语法直接调用程序：

!wget -O example_output_file.html https://example.com