use response.selector in link extractors instead of instantiating new Selector

Author: eliasdorneles

scrapy/linkextractors/lxmlhtml.py

@@ -65,9 +65,8 @@ def _extract_links(self, selector, response_url, response_encoding, base_url):
                 if self.unique else links
 
     def extract_links(self, response):
-        html = Selector(response)
         base_url = get_base_url(response)
-        return self._extract_links(html, response.url, response.encoding, base_url)
+        return self._extract_links(response.selector, response.url, response.encoding, base_url)
 
     def _process_links(self, links):
         """ Normalize and filter extracted links
@@ -95,14 +94,13 @@ def __init__(self, allow=(), deny=(), allow_domains=(), deny_domains=(), restric
             canonicalize=canonicalize, deny_extensions=deny_extensions)
 
     def extract_links(self, response):
-        html = Selector(response)
         base_url = get_base_url(response)
         if self.restrict_xpaths:
             docs = [subdoc
                     for x in self.restrict_xpaths
-                    for subdoc in html.xpath(x)]
+                    for subdoc in response.xpath(x)]
         else:
-            docs = [html]
+            docs = [response.selector]
         all_links = []
         for doc in docs:
             links = self._extract_links(doc, response.url, response.encoding, base_url)

scrapy/linkextractors/sgml.py

@@ -127,7 +127,7 @@ def __init__(self, allow=(), deny=(), allow_domains=(), deny_domains=(), restric
     def extract_links(self, response):
         base_url = None
         if self.restrict_xpaths:
-            sel = Selector(response)
+            sel = response.selector
             base_url = get_base_url(response)
             body = u''.join(f
                             for x in self.restrict_xpaths