Python爬虫实战（二）：爬百度贴吧

代码：

# _*_ coding:utf-8 _*_
import urllib
import urllib2
import re
class Tool:
    removingImg = re.compile('<img.*?>| {7}|')
    removingAddr = re.compile('<a.*?>|</a>')
    replaceLine = re.compile('<tr>|<div>|</div>|</p>')
    replaceTD = re.compile('<td>')
    replacePara = re.compile('<p.*?>')
    replaceBR = re.compile('<br><br>|<br>')
    removeExtraTag = re.compile('<.*?>')

    def replace(self,x):
        x = re.sub(self.removingImg,"",x)
        x = re.sub(self.removingAddr,"",x)
        x = re.sub(self.replaceLine,"\n",x)
        x = re.sub(self.replaceTD,"\t",x)
        x = re.sub(self.replacePara,"\n",x)
        x = re.sub(self.replaceBR,"\n",x)
        x = re.sub(self.removeExtraTag,"",x)
        return x.strip()

class BDTB:
    def __init__(self,baseUrl,seeLZ,floorTag):
        self.baseURL = baseUrl
        self.seeLZ = '?see_lz='+str(seeLZ)
        self.tool = Tool()
        self.file = None
        self.floor = 1
        self.defaultTitle = '百度贴吧'
        self.floorTag = floorTag

    def getPage(self,pageNum):
        try:
            url = self.baseURL + self.seeLZ + '&pn=' + str(pageNum)
            request = urllib2.Request(url)
            response = urllib2.urlopen(request)
            pageCode = response.read().decode('utf-8')
            #print pageCode
            return pageCode
        except urllib2.URLError,e:
            if hasattr(e,"reason"):
                print u"连接百度贴吧失败，错误原因",e.reason
                return None

    def getTitle(self,page):
         pattern = re.compile('<h3 class="core_title_txt.*?>(.*?)</h3>',re.S)
         result = re.search(pattern,page)
         if result:
             #print result.group(1)
             return result.group(1).strip()
         else:
             #print "Not match"
             return None

    def getPageNum(self,page):
         pattern = re.compile('<li class="l_reply_num.*?</span>.*?<span.*?>(.*?)</span>',re.S)
         result = re.search(pattern,page)
         if result:
             #print result.group(1)
             return result.group(1).strip()
         else:
             #print "Not match"
             return None

    def getContent(self,page):
        pattern = re.compile('<div id="post_content_.*?>(.*?)</div>',re.S)
        items = re.findall(pattern,page)
        contents = []
        for item in items:
            #print floor,u"楼-----------------------------------------\n"
            content = "\n" + self.tool.replace(item) + "\n"
            contents.append(content.encode('utf-8'))
            #floor += 1
        return contents

    def setFileTitle(self,title):
        if title is not None:
            self.file = open(title + ".txt","w+")
        else:
            self.file = open(self.defaultTitle + ".txt","w+")

    def writeData(self,contents):
        for item in contents:
            if self.floorTag == '':
                floorLine = "\n" + str(self.floor) + u"------------------------------------------------------\n"
                self.file.write(floorLine)
            self.file.write(item);
            self.floor += 1

    def start(self):
        indexPage = self.getPage(1)
        pageNum = self.getPageNum(indexPage)
        title = self.getTitle(indexPage)
        self.setFileTitle(title)
        if pageNum == None:
            print "URL已失效，请重试"
            return
        try:
            print "该帖子共有" + str(pageNum) + "页"
            for i in range(1,int(pageNum)+1):
                print "正在写入第" + str(i) + "页数据"
                page = self.getPage(i)
                contents = self.getContent(page)
                self.writeData(contents)
        except IOError,e:
            print "写入异常，原因" + e.message
        finally:
            print "写入任务完成"

print u"请输入帖子代号"
baseURL = "http://tieba.baidu.com/p/" + str(raw_input(u'http://tieba.baidu.com/p/'))
seeLZ = raw_input("是否只获取楼主发言，是输入1，否输入0\n")
floorTag = raw_input("是否写入楼层信息，是输入1，否输入0\n")
bdtb = BDTB(baseURL,seeLZ,floorTag)
bdtb.start()
#baseURL = 'http://tieba.baidu.com/p/3138733512'
#bdtb = BDTB(baseURL,1)
#page = bdtb.getPage(1)
#bdtb.getTitle()
#bdtb.getPageNum()
#bdtb.getContent(page)