title: Scrapy sqmllinkextractor rule changes urls
body: <p>I'm trying to build a webcrawler spider using Scrapy and I've set up a Rule for the links I want my crawler to pick up using a regex: </p>
  
  <pre><code>rules = (Rule(SgmlLinkExtractor(allow='http\:\/\/www\.cartelera\.com\.uy\/apeliculafunciones\.aspx\?[^"]*1&amp;29'), 'parse_loly', follow=True, ),)
  </code></pre>
  
  <p>I checked the regex and it works and it matches the links I want the spider to crawl, but when I ran the program, the spider found no items and with a little checking I found out that while the regex matches the items correctly, when the spider goes to crawl the page the url it uses is different than it should be.</p>
  
  <p>For example, the spider should match and crawl urls such as</p>
  
  <pre><code>http://www.cartelera.com.uy/apeliculafunciones.aspx?7242&amp;&amp;CINE&amp;OBRA&amp;-1&amp;29
  http://www.cartelera.com.uy/apeliculafunciones.aspx?10704&amp;&amp;CINE&amp;OBRA&amp;-1&amp;29
  http://www.cartelera.com.uy/apeliculafunciones.aspx?10697&amp;&amp;CINE&amp;OBRA&amp;-1&amp;29
  </code></pre>
  
  <p>But the urls scrapy crawls  come out like</p>
  
  <pre><code>http://www.cartelera.com.uy/apeliculafunciones.aspx?-1=&amp;29=&amp;7242=&amp;CINE=&amp;OBRA=
  http://www.cartelera.com.uy/apeliculafunciones.aspx?-1=&amp;29=&amp;10704=&amp;CINE=&amp;OBRA=
  http://www.cartelera.com.uy/apeliculafunciones.aspx?-1=&amp;29=&amp;10697=&amp;CINE=&amp;OBRA=
  </code></pre>
  
  <p>These urls lead to error pages so, obviously, no items are found.</p>
  
  <p>There are no error messages
  Why is this happening and how do I avoid it?</p>
  
  <p>Pasting my class code below</p>
  
  <pre><code>class MySpider(CrawlSpider):
      name = 'cartelera'
      allowed_domains = ["www.cartelera.com.uy"]
      start_urls = ["http://www2.cartelera.com.uy/apeliculafunciones.aspx?,,PELICULAS,OBRA,0,26"]
  
      rules = (Rule(SgmlLinkExtractor(allow='http\:\/\/www\.cartelera\.com\.uy\/apeliculafunciones\.aspx\?[^"]*1&amp;29'), 'parse_loly', follow=True, ),)
  
  ##simple debugging method to output and check the crawled urls
  def parse_loly(self, response):
  print '%s' % response.url
  return
  </code></pre>