我有一个小工具，我用来从一个网站上下载一个MP3文件，然后构建/更新一个播客XML文件，我已经添加到iTunes。
创建/更新XML文件的文本处理是用Python编写的。但是，我在Windows .bat文件中使用wget来下载实际的MP3文件。我更喜欢用Python编写整个实用程序。
我努力寻找一种用Python实际下载该文件的方法，因此我使用了wget。
那么，如何使用Python下载文件呢?
当前回答
我想从网页上下载所有的文件。我尝试了wget，但它失败了，所以我决定使用Python路由，我找到了这个线程。
读完之后，我做了一个小的命令行应用程序，soupget，扩展了PabloG和Stan的优秀答案，并添加了一些有用的选项。
它使用BeatifulSoup收集页面的所有url，然后下载具有所需扩展名的url。最后，它可以同时下载多个文件。
下面就是:
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from __future__ import (division, absolute_import, print_function, unicode_literals)
import sys, os, argparse
from bs4 import BeautifulSoup
# --- insert Stan's script here ---
# if sys.version_info >= (3,):
#...
#...
# def download_file(url, dest=None):
#...
#...
# --- new stuff ---
def collect_all_url(page_url, extensions):
"""
Recovers all links in page_url checking for all the desired extensions
"""
conn = urllib2.urlopen(page_url)
html = conn.read()
soup = BeautifulSoup(html, 'lxml')
links = soup.find_all('a')
results = []
for tag in links:
link = tag.get('href', None)
if link is not None:
for e in extensions:
if e in link:
# Fallback for badly defined links
# checks for missing scheme or netloc
if bool(urlparse.urlparse(link).scheme) and bool(urlparse.urlparse(link).netloc):
results.append(link)
else:
new_url=urlparse.urljoin(page_url,link)
results.append(new_url)
return results
if __name__ == "__main__": # Only run if this file is called directly
# Command line arguments
parser = argparse.ArgumentParser(
description='Download all files from a webpage.')
parser.add_argument(
'-u', '--url',
help='Page url to request')
parser.add_argument(
'-e', '--ext',
nargs='+',
help='Extension(s) to find')
parser.add_argument(
'-d', '--dest',
default=None,
help='Destination where to save the files')
parser.add_argument(
'-p', '--par',
action='store_true', default=False,
help="Turns on parallel download")
args = parser.parse_args()
# Recover files to download
all_links = collect_all_url(args.url, args.ext)
# Download
if not args.par:
for l in all_links:
try:
filename = download_file(l, args.dest)
print(l)
except Exception as e:
print("Error while downloading: {}".format(e))
else:
from multiprocessing.pool import ThreadPool
results = ThreadPool(10).imap_unordered(
lambda x: download_file(x, args.dest), all_links)
for p in results:
print(p)
它的用法示例如下:
python3 soupget.py -p -e <list of extensions> -d <destination_folder> -u <target_webpage>
还有一个实际的例子，如果你想看到它的作用:
python3 soupget.py -p -e .xlsx .pdf .csv -u https://healthdata.gov/dataset/chemicals-cosmetics
其他回答
我写了下面的代码，它可以在普通的Python 2或Python 3中工作。
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()
注:
支持“进度条”回调。 从我的网站上下载一个4 MB的测试包。zip。
还有一个，使用urlretrieve:
import urllib.request
urllib.request.urlretrieve("http://www.example.com/songs/mp3.mp3", "mp3.mp3")
(对于Python 2使用import urllib和urllib.urlretrieve)
如果速度对你来说很重要，我为urllib和wget模块做了一个小的性能测试，关于wget，我尝试了一次状态栏和一次没有状态栏。我使用了三个不同的500MB文件进行测试(不同的文件-以消除在底层进行缓存的可能性)。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“profile”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
我想从网页上下载所有的文件。我尝试了wget，但它失败了，所以我决定使用Python路由，我找到了这个线程。
读完之后，我做了一个小的命令行应用程序，soupget，扩展了PabloG和Stan的优秀答案，并添加了一些有用的选项。
它使用BeatifulSoup收集页面的所有url，然后下载具有所需扩展名的url。最后，它可以同时下载多个文件。
下面就是:
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from __future__ import (division, absolute_import, print_function, unicode_literals)
import sys, os, argparse
from bs4 import BeautifulSoup
# --- insert Stan's script here ---
# if sys.version_info >= (3,):
#...
#...
# def download_file(url, dest=None):
#...
#...
# --- new stuff ---
def collect_all_url(page_url, extensions):
"""
Recovers all links in page_url checking for all the desired extensions
"""
conn = urllib2.urlopen(page_url)
html = conn.read()
soup = BeautifulSoup(html, 'lxml')
links = soup.find_all('a')
results = []
for tag in links:
link = tag.get('href', None)
if link is not None:
for e in extensions:
if e in link:
# Fallback for badly defined links
# checks for missing scheme or netloc
if bool(urlparse.urlparse(link).scheme) and bool(urlparse.urlparse(link).netloc):
results.append(link)
else:
new_url=urlparse.urljoin(page_url,link)
results.append(new_url)
return results
if __name__ == "__main__": # Only run if this file is called directly
# Command line arguments
parser = argparse.ArgumentParser(
description='Download all files from a webpage.')
parser.add_argument(
'-u', '--url',
help='Page url to request')
parser.add_argument(
'-e', '--ext',
nargs='+',
help='Extension(s) to find')
parser.add_argument(
'-d', '--dest',
default=None,
help='Destination where to save the files')
parser.add_argument(
'-p', '--par',
action='store_true', default=False,
help="Turns on parallel download")
args = parser.parse_args()
# Recover files to download
all_links = collect_all_url(args.url, args.ext)
# Download
if not args.par:
for l in all_links:
try:
filename = download_file(l, args.dest)
print(l)
except Exception as e:
print("Error while downloading: {}".format(e))
else:
from multiprocessing.pool import ThreadPool
results = ThreadPool(10).imap_unordered(
lambda x: download_file(x, args.dest), all_links)
for p in results:
print(p)
它的用法示例如下:
python3 soupget.py -p -e <list of extensions> -d <destination_folder> -u <target_webpage>
还有一个实际的例子，如果你想看到它的作用:
python3 soupget.py -p -e .xlsx .pdf .csv -u https://healthdata.gov/dataset/chemicals-cosmetics
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)
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