简单爬虫爬取百度贴吧

import urllib.requestimport urllib.parseimport osimport sslssl._create_default_https_context = ssl._create_unverified_context#定义生成request对象方法def request_handle(base_url,bar_name,page):    #构造参数    pn = (page-1)*50    data = {        'kw':bar_name,        'pn':pn    }    data = urllib.parse.urlencode(data)    #根据参数，生成对应的url    url = base_url+data    #构造headers    headers = {        'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.108 Safari/537.36'    }    request = urllib.request.Request(url=url)    #返回request对象    return request#定义下载方法def download(request,page,bar_name):    response = urllib.request.urlopen(request)    if not os.path.exists(bar_name):        os.mkdir(os.path.join(os.getcwd(),bar_name))    filename = '第'+str(page)+'页.html'    filepath = os.path.join(bar_name,filename)    with open(filepath,'wb') as f1:        f1.write(response.read())#主函数def main():    bar_name = input('请输入您想爬取的吧名：')    start_page = int(input('请输入您想爬取的起始页码：'))    end_page = int(input('请输入您想爬取的结束页面：'))    base_url = 'http://tieba.baidu.com/f?ie=utf-8&'    #遍历需要爬取的页码，依次开始爬取内容    for page in range(start_page,end_page+1):        #构造reuest请求        request = request_handle(base_url,bar_name,page)        # 执行爬取函数，开始爬取        print('开始下载第：' + str(page) + '页')        download(request,page,bar_name)        print('结束下载第：' + str(page) + '页')