[python]百度贴吧爬虫
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eg.
爬取西安交通大学吧内容,并以['url':page_url,'title':title,'para':reply]形式存储到MongoDB数据库。
一、相关信息介绍
爬虫是一段自动抓取互联网信息的程序。一般情况下采取人工方式从互联网上获取少量的信息,爬虫可以从一个URL出发,访问它所关联的URL,并且从每个页面中获取有价值数据。
这是轻量级(无需登录和异步加载的静态网页的抓取)网络爬虫的开发,采用python语言编写,主要包括URL管理器、网页下载器(urllib2)、网页解析器(BeautifulSoup),实现百度贴吧网络爬虫相关的页面数据,简单爬虫的架构如下:
简单爬虫架构流程如下:
二、程序按照架构分为以下五个主要的py文件:
config.py -- 配置MongoDB相关信息
from pymongo import MongoClientconn = MongoClient('127.0.0.1',27017)db_crawl = conn.mydb_crawl #连接mydb_test数据库,没有则自动创建my_crawl = db_crawl.test_crawl #使用test_set集合,没有则自动创建
主调度文件为TieBaCrawl.py
# coding:utf8import html_parserimport url_managerfrom Crawl import html_downloaderclass SpiderMain(object): def __init__(self): self.urls = url_manager.UrlManager() self.downloader = html_downloader.HtnlDownloader() self.parser = html_parser.HtmlParser() def craw(self, root_url): count = 1 self.urls.add_new_url(root_url) while self.urls.has_new_url(): try: new_url = self.urls.get_new_url() print ('craw %d :%s' % (count, new_url)) html_cont = self.downloader.download(new_url) new_urls = self.parser.parse(new_url, html_cont) self.urls.add_new_urls(new_urls) # if count == 100: # break count = count + 1 except: print ('craw failed')if __name__ == "__main__": root_url = "http://tieba.baidu.com/f?kw=%E8%A5%BF%E5%AE%89%E4%BA%A4%E9%80%9A%E5%A4%A7%E5%AD%A6&traceid=" obj_spider = SpiderMain() obj_spider.craw(root_url)
URL管理器 url_manager.py
# coding:utf8class UrlManager(object): def __init__(self): self.new_urls = set() self.old_urls = set() def add_new_url(self, url): if url is None: return if url not in self.new_urls and url not in self.old_urls: self.new_urls.add(url) def add_new_urls(self, urls): if urls is None or len(urls) == 0: return for url in urls: self.add_new_url(url) def has_new_url(self): return len(self.new_urls) != 0 def get_new_url(self): new_url = self.new_urls.pop() self.old_urls.add(new_url) return new_url
html下载器 html_downloader.py
# coding:utf8import urllibfrom urllib import requestclass HtnlDownloader(object): def download(self, url): if url is None: print("url is None") return None response = urllib.request.urlopen(url) if response.getcode() != 200: # ==200网络请求成功的意思,返回这个状态表示已经获取到数据了 print("response.getcode():", response.getcode(),"!=200") return return response.read()
html解析器 html_parser.py
# coding:utf8import refrom urllib import parsefrom bs4 import BeautifulSoupfrom Crawl.config import *class HtmlParser(object): def _get_new_urls(self, page_url, soup): new_urls = set() links = soup.find_all('a',href=re.compile(r".*\/p\/.*")) #匹配帖子的href for link in links: new_url = link['href'] new_full_url = parse.urljoin(page_url, new_url) new_urls.add(new_full_url) return new_urls def _get_new_data(self, page_url, soup): str_ = [] title_node = soup.find('title')#贴吧首页每个帖子都是一个title,点进去每个帖子的title也有标识 title = title_node.get_text() # print("title:",title) if soup.find('a',rel = r"noreferrer") is not None: para_node = soup.find_all('a', rel=r"noreferrer") else: para_node = soup.find_all('div',class_="d_post_content_main") # print(len(para_node)) for node in para_node: try: temp = node.get_text() temp = str(temp).replace(" ","").replace("\n","") if temp is not "": if temp in title: #不能获取帖子里二级及其以后的回复内容 print(temp,"in title:",title,"跳过") else: str_.append(temp) except: pass my_crawl.insert([{'url':page_url,'title':title,'para':str_}]) #将URL、title、para插入数据库 def parse(self, page_url, html_cont): if page_url is None or html_cont is None: return soup = BeautifulSoup(html_cont, 'html.parser', from_encoding='utf-8') new_urls = self._get_new_urls(page_url, soup) self._get_new_data(page_url,soup) return new_urls
三、运行结果存储于MongoDB,RoBo 3T可视化显示如下:
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