给定wget命令的Python等效项

Question 1

我正在尝试创建一个与此wget命令具有相同功能的Python函数：

wget -c --read-timeout=5 --tries=0 "$URL"

-c -如果下载中断，请从上次中断的地方继续。

--read-timeout=5-如果5秒钟内没有新数据输入，请放弃并重试。鉴于-c此，它将从上次中断的地方再次尝试。

--tries=0 -永远重试。

串联使用的这三个参数导致下载不会失败。

我想在我的Python脚本中复制这些功能，但是我不知道从哪里开始...

Question 2

urllib.request应该可以工作。只需在一段时间（未完成）循环中进行设置，检查本地文件是否已存在，是否发送带有RANGE标头的GET，并指定下载本地文件的距离。确保使用read（）附加到本地文件，直到发生错误。

这也可能是Python urllib2的副本，当网络重新连接时，恢复下载不起作用

Question 3

还有一个名为Python的漂亮模块wget，非常易于使用。在这里找到。

这证明了设计的简单性：

>>> import wget
>>> url = 'http://www.futurecrew.com/skaven/song_files/mp3/razorback.mp3'
>>> filename = wget.download(url)
100% [................................................] 3841532 / 3841532>
>> filename
'razorback.mp3'

请享用。

但是，如果wget不起作用（某些PDF文件有问题），请尝试此解决方案。

编辑：您还可以使用该out参数来使用自定义输出目录，而不是当前工作目录。

>>> output_directory = <directory_name>
>>> filename = wget.download(url, out=output_directory)
>>> filename
'razorback.mp3'

Question 4

import urllib2
import time

max_attempts = 80
attempts = 0
sleeptime = 10 #in seconds, no reason to continuously try if network is down

#while true: #Possibly Dangerous
while attempts < max_attempts:
    time.sleep(sleeptime)
    try:
        response = urllib2.urlopen("http://example.com", timeout = 5)
        content = response.read()
        f = open( "local/index.html", 'w' )
        f.write( content )
        f.close()
        break
    except urllib2.URLError as e:
        attempts += 1
        print type(e)

Question 5

我必须在没有将正确的选项编译到wget中的linux版本上执行类似的操作。本示例用于下载内存分析工具“ guppy”。我不确定它是否重要，但是我将目标文件的名称与url目标名称保持一致...

这是我想出的：

python -c "import requests; r = requests.get('https://pypi.python.org/packages/source/g/guppy/guppy-0.1.10.tar.gz') ; open('guppy-0.1.10.tar.gz' , 'wb').write(r.content)"

那是一线，这更具可读性：

import requests
fname = 'guppy-0.1.10.tar.gz'
url = 'https://pypi.python.org/packages/source/g/guppy/' + fname
r = requests.get(url)
open(fname , 'wb').write(r.content)

这适用于下载tarball。我能够解压缩该软件包，并在下载后将其下载。

编辑：

为了解决一个问题，这是一个带有打印到STDOUT的进度条的实现。不用clint软件包，可以采用一种更便携式的方法来执行此操作，但这已在我的机器上经过测试，可以正常工作：

#!/usr/bin/env python

from clint.textui import progress
import requests

fname = 'guppy-0.1.10.tar.gz'
url = 'https://pypi.python.org/packages/source/g/guppy/' + fname

r = requests.get(url, stream=True)
with open(fname, 'wb') as f:
    total_length = int(r.headers.get('content-length'))
    for chunk in progress.bar(r.iter_content(chunk_size=1024), expected_size=(total_length/1024) + 1): 
        if chunk:
            f.write(chunk)
            f.flush()

Question 6

我经常发现更简单，更可靠的解决方案是，只需在python中执行终端命令。在您的情况下：

import os
url = 'https://www.someurl.com'
os.system(f"""wget -c --read-timeout=5 --tries=0 "{url}"""")

Question 7

对于Windows和Python 3.x，我为下载文件重命名花费了两分钱：

安装wget模块：pip install wget
使用wget：

import wget
wget.download('Url', 'C:\\PathToMyDownloadFolder\\NewFileName.extension')

真正有效的命令行示例：

python -c "import wget; wget.download(""https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.17.2.tar.xz"", ""C:\\Users\\TestName.TestExtension"")"

注意：“ C：\\ PathToMyDownloadFolder \\ NewFileName.extension”不是必需的。默认情况下，该文件未重命名，并且下载文件夹是您的本地路径。

Question 8

这是torchvision库采用的代码：

import urllib

def download_url(url, root, filename=None):
    """Download a file from a url and place it in root.
    Args:
        url (str): URL to download file from
        root (str): Directory to place downloaded file in
        filename (str, optional): Name to save the file under. If None, use the basename of the URL
    """

    root = os.path.expanduser(root)
    if not filename:
        filename = os.path.basename(url)
    fpath = os.path.join(root, filename)

    os.makedirs(root, exist_ok=True)

    try:
        print('Downloading ' + url + ' to ' + fpath)
        urllib.request.urlretrieve(url, fpath)
    except (urllib.error.URLError, IOError) as e:
        if url[:5] == 'https':
            url = url.replace('https:', 'http:')
            print('Failed download. Trying https -> http instead.'
                    ' Downloading ' + url + ' to ' + fpath)
            urllib.request.urlretrieve(url, fpath)

如果您可以依赖Torchvision库，那么您也可以简单地执行以下操作：

from torchvision.datasets.utils import download_url
download_url('http://something.com/file.zip', '~/my_folder`)

Question 9

让我为线程提供一个示例，以防您要下载许多文件。

import math
import random
import threading

import requests
from clint.textui import progress

# You must define a proxy list
# I suggests https://free-proxy-list.net/
proxies = {
    0: {'http': 'http://34.208.47.183:80'},
    1: {'http': 'http://40.69.191.149:3128'},
    2: {'http': 'http://104.154.205.214:1080'},
    3: {'http': 'http://52.11.190.64:3128'}
}


# you must define the list for files do you want download
videos = [
    "https://i.stack.imgur.com/g2BHi.jpg",
    "https://i.stack.imgur.com/NURaP.jpg"
]

downloaderses = list()


def downloaders(video, selected_proxy):
    print("Downloading file named {} by proxy {}...".format(video, selected_proxy))
    r = requests.get(video, stream=True, proxies=selected_proxy)
    nombre_video = video.split("/")[3]
    with open(nombre_video, 'wb') as f:
        total_length = int(r.headers.get('content-length'))
        for chunk in progress.bar(r.iter_content(chunk_size=1024), expected_size=(total_length / 1024) + 1):
            if chunk:
                f.write(chunk)
                f.flush()


for video in videos:
    selected_proxy = proxies[math.floor(random.random() * len(proxies))]
    t = threading.Thread(target=downloaders, args=(video, selected_proxy))
    downloaderses.append(t)

for _downloaders in downloaderses:
    _downloaders.start()

Question 10

像py一样简单：

class Downloder():
    def download_manager(self, url, destination='Files/DownloderApp/', try_number="10", time_out="60"):
        #threading.Thread(target=self._wget_dl, args=(url, destination, try_number, time_out, log_file)).start()
        if self._wget_dl(url, destination, try_number, time_out, log_file) == 0:
            return True
        else:
            return False


    def _wget_dl(self,url, destination, try_number, time_out):
        import subprocess
        command=["wget", "-c", "-P", destination, "-t", try_number, "-T", time_out , url]
        try:
            download_state=subprocess.call(command)
        except Exception as e:
            print(e)
        #if download_state==0 => successfull download
        return download_state

Question 11

TensorFlow使生活更轻松。文件路径为我们提供了下载文件的位置。

import tensorflow as tf
tf.keras.utils.get_file(origin='https://storage.googleapis.com/tf-datasets/titanic/train.csv',
                                    fname='train.csv',
                                    untar=False, extract=False)