爬虫系列---Scrapy框架学习

Posted 2020-10-29 TaoHF

项目的需求需要爬虫某网的商品信息，自己通过Requests,BeautifulSoup等编写了一个spider，把抓取的数据存到数据库里面。

 

跑起来的感觉速度有点慢，尤其是进入详情页面抓取信息的时候，小白入门，也不知道应该咋个整，反正就是跟着学嘛。

网上的爬虫框架还是挺多的，现在打算学习spcrapy重新写。

下面是记录官方文档的一些学习notes.

 

scrapy的环境是在anaconda里面搞得，所以子啊pycharm里面的 preject interpreter  选择anaconda下面的python.exe.

很多时候自己老是要忘记设置这个，会导致很多包都import不进来，，因为我很多包都是通过anaconda环境装的。

 

 

下面是给的第一个测试例子

 1 class QuotesSpider(scrapy.Spider):
 2     name = "quotes"
 3     start_urls = [
 4         \'http://quotes.toscrape.com/tag/humor/\',
 5     ]
 6 
 7     def parse(self, response):
 8         for quote in response.css(\'div.quote\'):
 9             yield {
10                 \'text\': quote.css(\'span.text::text\').extract_first(),
11                 \'author\': quote.xpath(\'span/small/text()\').extract_first(),
12             }
13 
14         next_page = response.css(\'li.next a::attr("href")\').extract_first()
15         if next_page is not None:
16             yield response.follow(next_page, self.parse)

 

在anaconda 的prompt里面输入命令

scrapy runspider quote_spider.py -o quote.json

注意要在文件所在的路径下面哦

运行成功后，会生成一个quote.json的文件

[
{"text": "\\u201cThe person, be it gentleman or lady, who has not pleasure in a good novel, must be intolerably stupid.\\u201d", "author": "Jane Austen"},
{"text": "\\u201cA day without sunshine is like, you know, night.\\u201d", "author": "Steve Martin"},
{"text": "\\u201cAnyone who thinks sitting in church can make you a Christian must also think that sitting in a garage can make you a car.\\u201d", "author": "Garrison Keillor"},
{"text": "\\u201cBeauty is in the eye of the beholder and it may be necessary from time to time to give a stupid or misinformed beholder a black eye.\\u201d", "author": "Jim Henson"},
{"text": "\\u201cAll you need is love. But a little chocolate now and then doesn\'t hurt.\\u201d", "author": "Charles M. Schulz"},
{"text": "\\u201cRemember, we\'re madly in love, so it\'s all right to kiss me anytime you feel like it.\\u201d", "author": "Suzanne Collins"},
{"text": "\\u201cSome people never go crazy. What truly horrible lives they must lead.\\u201d", "author": "Charles Bukowski"},
{"text": "\\u201cThe trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it.\\u201d", "author": "Terry Pratchett"},
{"text": "\\u201cThink left and think right and think low and think high. Oh, the thinks you can think up if only you try!\\u201d", "author": "Dr. Seuss"},
{"text": "\\u201cThe reason I talk to myself is because I\\u2019m the only one whose answers I accept.\\u201d", "author": "George Carlin"},
{"text": "\\u201cI am free of all prejudice. I hate everyone equally. \\u201d", "author": "W.C. Fields"},
{"text": "\\u201cA lady\'s imagination is very rapid; it jumps from admiration to love, from love to matrimony in a moment.\\u201d", "author": "Jane Austen"}
]

 

当你执行scrapy runspider quote_spider.py -o quote.json这条命令的时候，Scrapy会在这个文件里面去look for Spider的定义，找到后用scrapy的crawler engine运行。

 

通过向start_urls 属性中定义的URL发送请求，并调用默认回调方法parse，将响应对象作为参数传递，从而开始爬网。在parse回调中，我们使用CSS Selector循环引用元素，产生一个带有提取的引用文本和作者的Python字典，查找指向下一页的链接，并使用与parse回调相同的方法安排另一个请求