python爬虫框架talonspider简单介绍

1.为什么写这个？

一些简单的页面，无需用比较大的框架来进行爬取，自己纯手写又比较麻烦

因此针对这个需求写了talonspider:

•1.针对单页面的item提取 - 具体介绍点这里
•2.spider模块 - 具体介绍点这里

2.介绍&&使用

2.1.item

这个模块是可以独立使用的，对于一些请求比较简单的网站（比如只需要get请求），单单只用这个模块就可以快速地编写出你想要的爬虫，比如(以下使用python3，python2见examples目录)：

2.1.1.单页面单目标

比如要获取这个网址http://book.qidian.com/info/1004608738 的书籍信息，封面等信息，可直接这样写：

    import time
    from talonspider import Item, TextField, AttrField
    from pprint import pprint

    class TestSpider(Item):
      title = TextField(css_select='.book-info>h1>em')
      author = TextField(css_select='a.writer')
      cover = AttrField(css_select='a#bookImg>img', attr='src')

      def tal_title(self, title):
        return title

      def tal_cover(self, cover):
        return 'http:' + cover

    if __name__ == '__main__':
      item_data = TestSpider.get_item(url='http://book.qidian.com/info/1004608738')
      pprint(item_data)

具体见qidian_details_by_item.py

2.1.1.单页面多目标

比如获取豆瓣250电影首页展示的25部电影，这一个页面有25个目标，可直接这样写：

    from talonspider import Item, TextField, AttrField
    from pprint import pprint

    # 定义继承自item的爬虫类
    class DoubanSpider(Item):
      target_item = TextField(css_select='div.item')
      title = TextField(css_select='span.title')
      cover = AttrField(css_select='div.pic>a>img', attr='src')
      abstract = TextField(css_select='span.inq')

      def tal_title(self, title):
        if isinstance(title, str):
          return title
        else:
          return ''.join([i.text.strip().replace('\xa0', '') for i in title])

    if __name__ == '__main__':
      items_data = DoubanSpider.get_items(url='https://movie.douban.com/top250')
      result = []
      for item in items_data:
        result.append({
          'title': item.title,
          'cover': item.cover,
          'abstract': item.abstract,
        })
      pprint(result)

具体见douban_page_by_item.py

2.2.spider

当需要爬取有层次的页面时，比如爬取豆瓣250全部电影，这时候spider部分就派上了用场：

    # !/usr/bin/env python
    from talonspider import Spider, Item, TextField, AttrField, Request
    from talonspider.utils import get_random_user_agent


    # 定义继承自item的爬虫类
    class DoubanItem(Item):
      target_item = TextField(css_select='div.item')
      title = TextField(css_select='span.title')
      cover = AttrField(css_select='div.pic>a>img', attr='src')
      abstract = TextField(css_select='span.inq')

      def tal_title(self, title):
        if isinstance(title, str):
          return title
        else:
          return ''.join([i.text.strip().replace('\xa0', '') for i in title])


    class DoubanSpider(Spider):
      # 定义起始url，必须
      start_urls = ['https://movie.douban.com/top250']
      # requests配置
      request_config = {
        'RETRIES': 3,
        'DELAY': 0,
        'TIMEOUT': 20
      }
      # 解析函数 必须有
      def parse(self, html):
        # 将html转化为etree
        etree = self.e_html(html)
        # 提取目标值生成新的url
        pages = [i.get('href') for i in etree.cssselect('.paginator>a')]
        pages.insert(0, '?start=0&filter;=')
        headers = {
          "User-Agent": get_random_user_agent()
        }
        for page in pages:
          url = self.start_urls[0] + page
          yield Request(url, request_config=self.request_config, headers=headers, callback=self.parse_item)

      def parse_item(self, html):
        items_data = DoubanItem.get_items(html=html)
        # result = []
        for item in items_data:
          # result.append({
          #   'title': item.title,
          #   'cover': item.cover,
          #   'abstract': item.abstract,
          # })
          # 保存
          with open('douban250.txt', 'a+') as f:
            f.writelines(item.title + '\n')


    if __name__ == '__main__':
      DoubanSpider.start()

控制台：

    /Users/howie/anaconda3/envs/work3/bin/python /Users/howie/Documents/programming/python/git/talonspider/examples/douban_page_by_spider.py
    2017-06-07 23:17:30,346 - talonspider - INFO: talonspider started
    2017-06-07 23:17:30,693 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250
    2017-06-07 23:17:31,074 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=25&filter;=
    2017-06-07 23:17:31,416 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=50&filter;=
    2017-06-07 23:17:31,853 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=75&filter;=
    2017-06-07 23:17:32,523 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=100&filter;=
    2017-06-07 23:17:33,032 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=125&filter;=
    2017-06-07 23:17:33,537 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=150&filter;=
    2017-06-07 23:17:33,990 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=175&filter;=
    2017-06-07 23:17:34,406 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=200&filter;=
    2017-06-07 23:17:34,787 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=225&filter;=
    2017-06-07 23:17:34,809 - talonspider - INFO: Time usage：0:00:04.462108

    Process finished with exit code 0

此时当前目录会生成douban250.txt，具体见douban_page_by_spider.py。

3.说明

学习之作，待完善的地方还有很多，欢迎提意见，项目地址talonspider。