编写Python脚本批量下载DesktopNexus壁纸的教程

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我是靠谱客的博主真实自行车，最近开发中收集的这篇文章主要介绍编写Python脚本批量下载DesktopNexus壁纸的教程，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

DesktopNexus 是我最喜爱的一个壁纸下载网站，上面有许多高质量的壁纸，几乎每天必上，每月也必会坚持分享我这个月来收集的壁纸

但是 DesktopNexus 壁纸的下载很麻烦，而且因为壁纸会通过浏览器检测你当前分辨率来展示合适你当前分辨率的壁纸，再加上是国外的网站，速度上很不乐观。

于是我写了个脚本，检测输入的页面中壁纸页面的链接，然后批量下载到指定文件夹中。

脚本使用 python 写的，所以需要机器上安装有 python 。
用法：

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

    -p 包含 DesktopNexus 壁纸链接的页面，比如我的壁纸分享
    -s 壁纸尺寸，可选，缺省为 1440x900
    -o 壁纸输出的文件夹，可选，缺省为当前目录下的 wallpapers，如果不存在会自动创建

代码：

#-*- 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'<a href=\"\/get\/%s\/\?t=(?P<token>.*?)\"' % 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) <= 70 and msg or msg[:67] + '...', progress))
    sys.stdout.flush()
    if progress >= 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()