编写Python脚本批量下载DesktopNexus壁纸的教程

$ python desktop_nexus.py -p http://www.desktopnexus.com/tag/cat/ -s 1280x800 -o wallpapers

#-*- coding: utf-8 -*-
from argparse import ArgumentParser

import os, re, sys
import urllib2, cookielib, urlparse

RE_WALLPAPER = r'http://[^/.]+.desktopnexus.com/wallpaper/d+/'
CHUNK_SIZE = 1024 * 3

class DesktopNexus:
 def __init__(self, page=None, size=None, output_dir=None):
 self.page = page
 self.size = size
 self.output_dir = output_dir

 def start(self):
 print 'Making output directory:', self.output_dir
 if not os.path.exists(self.output_dir):
 os.makedirs(self.output_dir)

 # Setup cookie
 cookie = cookielib.CookieJar()
 processer = urllib2.HTTPCookieProcessor(cookie)
 opener = urllib2.build_opener(processer)
 urllib2.install_opener(opener)

 self._read_page()

 def _get_pic_info(self, url):
 pic_id = url.split('/')[-2]
 html = urllib2.urlopen(url).read()
 pattern = r'.*?)"' % pic_id
 match = re.search(pattern, html, flags=re.I|re.M|re.S)
 if match:
 return {'id': pic_id,
 'token': match.group('token'),
 'size': self.size}
 else:
 raise Exception('Cound not find wallpaper')

 def _get_pic_file(self, pic_info):
 redirect_url = 'http://www.desktopnexus.com/dl/inline/%(id)s/%(size)s/%(token)s' % pic_info

 request = urllib2.urlopen(redirect_url)
 return request.geturl()

 def _download_pic(self, url):
 pic_info = self._get_pic_info(url)
 pic_file = self._get_pic_file(pic_info)
 filename = os.path.split(urlparse.urlparse(pic_file).path)[-1]
 filename = os.path.join(self.output_dir, filename)
 with open(filename, 'wb') as output:
 resp = urllib2.urlopen(pic_file)
 total_size = int(resp.info().get('Content-Length'))
 saved_size = 0.0
 while saved_size != total_size:
 chunk = resp.read(CHUNK_SIZE)
 saved_size += len(chunk)
 output.write(chunk)
 self._print_progress('Saving file: %s' % filename, 
 saved_size / total_size * 100)

 def _print_progress(self, msg, progress):
 sys.stdout.write('%-71s%3d%%
' 
 % (len(msg) <= 70 and msg or msg[:67] + '...', progress))
 sys.stdout.flush()
 if progress >= 100:
 sys.stdout.write('
')

 def _read_page(self):
 try:
 print 'Fetching content:', self.page
 html = urllib2.urlopen(self.page).read()
 links = set(re.findall(RE_WALLPAPER, html, re.M|re.I))
 count = len(links)

 print 'Downloading wallpapers:'
 for i, link in enumerate(links):
 print '[%d/%d]: %s' % (i + 1, count, link)
 try:
 self._download_pic(link)
 except Exception as e:
 print 'Error downloading wallpaper.', e.message
 except Exception as e:
 print 'Error fetching content.', e

if __name__ == '__main__':
 # Setup argparser
 parser = ArgumentParser('python desktop_nexus.py')
 parser.add_argument('-p', '--page', dest='page', required=True, 
 help='specific a page that includes wallpaper list')
 parser.add_argument('-s', '--size', dest='size', default='1440x900', 
 help='specific the wallpaper size, default to 1440x900')
 parser.add_argument('-o', '--output', dest='output_dir', default='wallpapers', 
 help='specific the output directory, default to "wallpapers"')
 args = parser.parse_args()
 dn = DesktopNexus(**args.__dict__)
 dn.start()