html_parser.py

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

from bs4 import BeautifulSoup
import re
import urllib.parse

class HtmlParser(object):

    def _get_new_urls(self, page_url, soup):
        new_urls = set()
        # /view/123.html
        links = soup.find_all('a', href=re.compile(r'/view/\d+\.htm')) # 不是html
        for link in links:
            new_url = link['href']
            # 让 new_url 以 page_url 为模板拼接成一个全新的 url
            new_full_url = urllib.parse.urljoin(page_url, new_url)
            print(new_url) # /view/10812319.htm
            print(new_full_url) # http://baike.baidu.com/view/10812319.htm
            new_urls.add(new_full_url)
        return new_urls


    def _get_new_data(self, page_url, soup):
        res_data = {}

        # url
        res_data['url'] = page_url

         # <dd class="lemmaWgt-lemmaTitle-title"> <h1>Python</h1>
        title_node = soup.find('dd', class_="lemmaWgt-lemmaTitle-title")
        # 如果没找到 'lemmaWgt-lemmaTitle-title' 类，直接跳过
        if title_node == None:
            res_data['title'] = ''
            res_data['summary'] = ''
            return res_data
        else:
            title_node = title_node.find("h1")
            res_data['title'] = title_node.get_text()

        # <div class="lemma-summary">
        summary_node = soup.find('div', class_="lemma-summary")
        if summary_node == None:
            res_data['summary'] = ''
        else:
            res_data['summary'] = summary_node.get_text()

        return res_data

    def paser(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)
        new_data = self._get_new_data(page_url, soup)
        return new_urls, new_data

# python3对urllib和urllib2进行了重构，
# 拆分成了urllib.request, urllib.response, urllib.parse, urllib.error等几个子模块，
# urljoin现在对应的函数是urllib.parse.urljoin