title: How can scrapy crawl more urls?
body: <p>as we see:</p>
  
  <pre><code>def parse(self, response):
      hxs = HtmlXPathSelector(response)
      sites = hxs.select('//ul/li')
      items = []
  
      for site in sites:
          item = Website()
          item['name'] = site.select('a/text()').extract()
          item['url'] = site.select('//a[contains(@href, "http")]/@href').extract()
          item['description'] = site.select('text()').extract()
          items.append(item)
  
      return items
  </code></pre>
  
  <p>scrapy just get a page response,and find urls in the page response.  I think it is just a surface crawl ！！</p>
  
  <p>But  I want more urls with the definded depth .</p>
  
  <p>what can I do to implement it ??</p>
  
  <p>thank you!!</p>