python定向爬虫校园论坛帖子信息

引言

写这个小爬虫主要是为了爬校园论坛上的实习信息，主要采用了Requests库

源码

URLs.py

主要功能是根据一个初始url（包含page页面参数）来获得page页面从当前页面数到pageNum的url列表

import re

def getURLs(url, attr, pageNum=1):
  all_links = []
  try:
    now_page_number = int(re.search(attr+'=(\d+)', url, re.S).group(1))
    for i in range(now_page_number, pageNum + 1):
      new_url = re.sub(attr+'=\d+', attr+'=%s' % i, url, re.S)
      all_links.append(new_url)
    return all_links
  except TypeError:
    print "arguments TypeError:attr should be string."

uni_2_native.py

由于论坛上爬取得到的网页上的中文都是unicode编码的形式，文本格式都为 &#XXXX;的形式，所以在爬得网站内容后还需要对其进行转换

import sys
import re
reload(sys)
sys.setdefaultencoding('utf-8')

def get_native(raw):
  tostring = raw
  while True:
    obj = re.search('&#(.*?);', tostring, flags=re.S)
    if obj is None:
      break
    else:
      raw, code = obj.group(0), obj.group(1)
      tostring = re.sub(raw, unichr(int(code)), tostring)
  return tostring

存入SQLite数据库：saveInfo.py

# -*- coding: utf-8 -*-

import MySQLdb

class saveSqlite():
  def __init__(self):
    self.infoList = []

  def saveSingle(self, author=None, title=None, date=None, url=None,reply=0, view=0):
    if author is None or title is None or date is None or url is None:
      print "No info saved!"
    else:
      singleDict = {}
      singleDict['author'] = author
      singleDict['title'] = title
      singleDict['date'] = date
      singleDict['url'] = url
      singleDict['reply'] = reply
      singleDict['view'] = view
      self.infoList.append(singleDict)

  def toMySQL(self):
    conn = MySQLdb.connect(host='localhost', user='root', passwd='', port=3306, db='db_name', charset='utf8')
    cursor = conn.cursor()
    # sql = "select * from info"
    # n = cursor.execute(sql)
    # for row in cursor.fetchall():
    #   for r in row:
    #     print r
    #   print '\n'
    sql = "delete from info"
    cursor.execute(sql)
    conn.commit()

    sql = "insert into info(title,author,url,date,reply,view) values (%s,%s,%s,%s,%s,%s)"
    params = []
    for each in self.infoList:
      params.append((each['title'], each['author'], each['url'], each['date'], each['reply'], each['view']))
    cursor.executemany(sql, params)

    conn.commit()
    cursor.close()
    conn.close()

  def show(self):
    for each in self.infoList:
      print "author: "+each['author']
      print "title: "+each['title']
      print "date: "+each['date']
      print "url: "+each['url']
      print "reply: "+str(each['reply'])
      print "view: "+str(each['view'])
      print '\n'

if __name__ == '__main__':
  save = saveSqlite()
  save.saveSingle('网','aaa','2008-10-10 10:10:10','www.baidu.com',1,1)
  # save.show()
  save.toMySQL()

主要爬虫代码

import requests
from lxml import etree
from cc98 import uni_2_native, URLs, saveInfo

# 根据自己所需要爬的网站，伪造一个header
headers ={
  'Accept': '',
  'Accept-Encoding': '',
  'Accept-Language': '',
  'Connection': '',
  'Cookie': '',
  'Host': '',
  'Referer': '',
  'Upgrade-Insecure-Requests': '',
  'User-Agent': ''
}
url = 'http://www.cc98.org/list.asp?boardid=459&page=1&action='
cc98 = 'http://www.cc98.org/'

print "get infomation from cc98..."

urls = URLs.getURLs(url, "page", 50)
savetools = saveInfo.saveSqlite()

for url in urls:
  r = requests.get(url, headers=headers)
  html = uni_2_native.get_native(r.text)

  selector = etree.HTML(html)
  content_tr_list = selector.xpath('//form/table[@class="tableborder1 list-topic-table"]/tbody/tr')

  for each in content_tr_list:
    href = each.xpath('./td[2]/a/@href')
    if len(href) == 0:
      continue
    else:
      # print len(href)
      # not very well using for, though just one element in list
      # but I don't know why I cannot get the data by index
      for each_href in href:
        link = cc98 + each_href
      title_author_time = each.xpath('./td[2]/a/@title')

      # print len(title_author_time)
      for info in title_author_time:
        info_split = info.split('\n')
        title = info_split[0][1:len(info_split[0])-1]
        author = info_split[1][3:]
        date = info_split[2][3:]

      hot = each.xpath('./td[4]/text()')
      # print len(hot)
      for hot_num in hot:
        reply_view = hot_num.strip().split('/')
        reply, view = reply_view[0], reply_view[1]
      savetools.saveSingle(author=author, title=title, date=date, url=link, reply=reply, view=view)

print "All got! Now saving to Database..."
# savetools.show()
savetools.toMySQL()
print "ALL CLEAR! Have Fun!"

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