title: How can I make Scrapy issue a callback properly?
body: <p>I'm currently trying to work with the Scrapy framework to simply collect a bunch of URLs that I can store and sort later. However, I can't seem to get URLs to print or be stored in a file on callback, no matter what I've tried and adapted from other tutorials. Here's currently what I'm going for with my spider class for this particular example, choosing a small site:</p>
  
  <pre><code>from scrapy.contrib.spiders import CrawlSpider, Rule
  from scrapy.contrib.linkextractors.sgml import SgmlLinkExtractor
  from scrapy.selector import HtmlXPathSelector
  from crawler.items import CrawlerItem
  from scrapy import log
  
  class CrawlerSpider(CrawlSpider):
      name = 'crawler'
  
      allowed_domains = [
          "glauberkotaki.com"
      ]
  
      start_urls = [
          "http://www.glauberkotaki.com"
      ]
  
      rules = (
          Rule(SgmlLinkExtractor(allow=(), deny=('about.html'))),
          Rule(SgmlLinkExtractor(allow=('about.html')), callback='parseLink', follow="yes"),
      )
  
      def parseLink(self, response):
          x = HtmlXPathSelector(response)
          print(response.url)
          print("\n")
  </code></pre>
  
  <p>It crawls all of the pages of this site fine, but it doesn't print out anything at all, even when it comes across the webpage "www.glauberkotaki.com/about.html", which is what I was trying to test the code with. It seems to me there's an issue with the callback being called.</p>