Python爬虫抓取csdn博客

        昨天晚上为了下载保存某位csdn大牛的全部博文，写了一个爬虫来自动抓取文章并保存到txt文本，当然也可以 保存到html网页中。这样就可以不用Ctrl+C 和Ctrl+V了，非常方便，抓取别的网站也是大同小异。

为了解析抓取的网页，用到了第三方模块，BeautifulSoup，这个模块对于解析html文件非常有用，当然也可以自己使用正则表达式去解析，但是比较麻烦。

由于csdn网站的robots.txt文件中显示禁止任何爬虫，所以必须把爬虫伪装成浏览器，而且不能频繁抓取，得sleep一会再抓，使用频繁会被封ip的，但可以使用代理ip。

#-*- encoding: utf-8 -*-
'''
Created on 2014-09-18 21:10:39

@author: Mangoer
@email: [email protected]
'''

import urllib2
import re
from bs4 import BeautifulSoup
import random
import time

class CSDN_Blog_Spider:
     def __init__(self,url):

          print '\n'
          print('已启动网络爬虫。。。')
          print  '网页地址： ' + url

          user_agents = [
                    'Mozilla/5.0 (Windows; U; Windows NT 5.1; it; rv:1.8.1.11) Gecko/20071127 Firefox/2.0.0.11',
                    'Opera/9.25 (Windows NT 5.1; U; en)',
                    'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)',
                    'Mozilla/5.0 (compatible; Konqueror/3.5; Linux) KHTML/3.5.5 (like Gecko) (Kubuntu)',
                    'Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.12) Gecko/20070731 Ubuntu/dapper-security Firefox/1.5.0.12',
                    'Lynx/2.8.5rel.1 libwww-FM/2.14 SSL-MM/1.4.1 GNUTLS/1.2.9',
                    "Mozilla/5.0 (X11; Linux i686) AppleWebKit/535.7 (KHTML, like Gecko) Ubuntu/11.04 Chromium/16.0.912.77 Chrome/16.0.912.77 Safari/535.7",
                    "Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:10.0) Gecko/20100101 Firefox/10.0 ",
                   ]
          # use proxy ip 
          # ips_list = ['60.220.204.2:63000','123.150.92.91:80','121.248.150.107:8080','61.185.21.175:8080','222.216.109.114:3128','118.144.54.190:8118',
          #           '1.50.235.82:80','203.80.144.4:80']

          # ip = random.choice(ips_list)
          # print '使用的代理ip地址： ' + ip

          # proxy_support = urllib2.ProxyHandler({'http':'http://'+ip})
          # opener = urllib2.build_opener(proxy_support)
          # urllib2.install_opener(opener)

          agent = random.choice(user_agents)

          req = urllib2.Request(url)
          req.add_header('User-Agent',agent)
          req.add_header('Host','blog.csdn.net')
          req.add_header('Accept','*/*')
          req.add_header('Referer','http://blog.csdn.net/mangoer_ys?viewmode=list')
          req.add_header('GET',url)
          html = urllib2.urlopen(req)
          page = html.read().decode('gbk','ignore').encode('utf-8')

          self.page = page
          self.title = self.getTitle()
          self.content = self.getContent()
          self.saveFile()
          

     def printInfo(self):
          print('文章标题是：   '+self.title + '\n')         
          print('内容已经存储到out.txt文件中！')

     def getTitle(self):
          rex = re.compile('<title>(.*?)</title>',re.DOTALL)          
          match = rex.search(self.page)
          if match:
                return match.group(1)

          return 'NO TITLE'

     def getContent(self):
          bs = BeautifulSoup(self.page)
          html_content_list = bs.findAll('div',{'id':'article_content','class':'article_content'})
          html_content = str(html_content_list[0])

          rex_p = re.compile(r'(?:.*?)>(.*?)<(?:.*?)',re.DOTALL)
          p_list = rex_p.findall(html_content)


          content = ''
          for p in p_list:
               if p.isspace() or p == '':
                    continue
               content = content + p
          return content

     def saveFile(self):
          
          outfile = open('out.txt','a')
          outfile.write(self.content)

     def getNextArticle(self):
          bs2 = BeautifulSoup(self.page)
          html_nextArticle_list = bs2.findAll('li',{'class':'prev_article'})
          # print str(html_nextArticle_list[0])
          html_nextArticle = str(html_nextArticle_list[0])
          # print html_nextArticle

          rex_link = re.compile(r'<a href=\"(.*?)\"',re.DOTALL)
          link = rex_link.search(html_nextArticle)
          # print link.group(1)

          if link:
               next_url = 'http://blog.csdn.net' + link.group(1)
               return next_url

          return None




class Scheduler:
     def __init__(self,url):
          self.start_url = url

     def start(self):
          spider = CSDN_Blog_Spider(self.start_url)
          spider.printInfo()


          while True:
               if spider.getNextArticle():
                    spider = CSDN_Blog_Spider(spider.getNextArticle())
                    spider.printInfo()
               elif spider.getNextArticle() == None:
                    print 'All article haved been downloaded!'
                    break

               time.sleep(10)



#url = input('请输入CSDN博文地址：')
url = "http://blog.csdn.net/mangoer_ys/article/details/38427979"

Scheduler(url).start()