編寫Python腳本批量下載DesktopNexus壁紙的教程

更新時間：2015年05月06日 09:34:07 投稿：goldensun

這篇文章主要介紹了編寫Python腳本批量下載DesktopNexus壁紙的教程,相較于普通的爬蟲抓取,本文的下載壁紙教程還包括了設置所要下載的分辨率等功能的實現(xiàn),需要的朋友可以參考下

DesktopNexus 是我最喜愛的一個壁紙下載網站，上面有許多高質量的壁紙，幾乎每天必上，每月也必會堅持分享我這個月來收集的壁紙

但是 DesktopNexus 壁紙的下載很麻煩，而且因為壁紙會通過瀏覽器檢測你當前分辨率來展示合適你當前分辨率的壁紙，再加上是國外的網站，速度上很不樂觀。

于是我寫了個腳本，檢測輸入的頁面中壁紙頁面的鏈接，然后批量下載到指定文件夾中。

腳本使用 python 寫的，所以需要機器上安裝有 python 。
用法：

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

    -p 包含 DesktopNexus 壁紙鏈接的頁面，比如我的壁紙分享
    -s 壁紙尺寸，可選，缺省為 1440x900
    -o 壁紙輸出的文件夾，可選，缺省為當前目錄下的 wallpapers，如果不存在會自動創(chuàng)建

代碼：

#-*- 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'&lt;a href=\"\/get\/%s\/\?t=(?P&lt;token&gt;.*?)\"' % 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%%\r' \
        % (len(msg) &lt;= 70 and msg or msg[:67] + '...', progress))
    sys.stdout.flush()
    if progress &gt;= 100:
      sys.stdout.write('\n')

  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()

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