Scrapy - 項的使用

描述

Item 物件是 Python 的普通詞典。我們可以使用以下語法訪問類的屬性 −

>>> item = DmozItem()
>>> item['title'] = 'sample title'
>>> item['title']
'sample title'

將上述程式碼新增到以下示例中 −

import scrapy

from tutorial.items import DmozItem

class MyprojectSpider(scrapy.Spider):
   name = "project"
   allowed_domains = ["dmoz.org"]
   
   start_urls = [
      "http://www.dmoz.org/Computers/Programming/Languages/Python/Books/",
      "http://www.dmoz.org/Computers/Programming/Languages/Python/Resources/"
   ]
   def parse(self, response):
      for sel in response.xpath('//ul/li'):
         item = DmozItem()
         item['title'] = sel.xpath('a/text()').extract()
         item['link'] = sel.xpath('a/@href').extract()
         item['desc'] = sel.xpath('text()').extract()
         yield item

上述爬蟲的輸出將如下所述 −

[scrapy] DEBUG: Scraped from <200 
http://www.dmoz.org/Computers/Programming/Languages/Python/Books/>
   {'desc': [u' - By David Mertz; Addison Wesley. Book in progress, full text, 
      ASCII format. Asks for feedback. [author website, Gnosis Software, Inc.\n],
   'link': [u'http://gnosis.cx/TPiP/'],
   'title': [u'Text Processing in Python']}
[scrapy] DEBUG: Scraped from <200 
http://www.dmoz.org/Computers/Programming/Languages/Python/Books/>
   {'desc': [u' - By Sean McGrath; Prentice Hall PTR, 2000, ISBN 0130211192, 
      has CD-ROM. Methods to build XML applications fast, Python tutorial, DOM and 
      SAX, new Pyxie open source XML processing library. [Prentice Hall PTR]\n'],
   'link': [u'http://www.informit.com/store/product.aspx?isbn=0130211192'],
   'title': [u'XML Processing with Python']}