Add Response.urljoin() helper

docs/topics/request-response.rst

@@ -493,6 +493,18 @@ Response objects
        given new values by whichever keyword arguments are specified. The
        attribute :attr:`Response.meta` is copied by default.
 
+    .. method:: Response.urljoin(url)
+
+        Constructs an absolute url by combining the Response's :attr:`url` with
+        a possible relative url.
+
+        This is a wrapper over `urlparse.urljoin`_, it's merely an alias for
+        making this call::
+
+            urlparse.urljoin(response.url, url)
+
+.. _urlparse.urljoin: https://docs.python.org/2/library/urlparse.html#urlparse.urljoin
+
 .. _topics-request-response-ref-response-subclasses:
 
 Response subclasses

scrapy/http/response/__init__.py

@@ -7,6 +7,8 @@ See documentation in docs/topics/request-response.rst
 
 import copy
 
+from six.moves.urllib.parse import urljoin
+
 from scrapy.http.headers import Headers
 from scrapy.utils.trackref import object_ref
 from scrapy.http.common import obsolete_setter
@@ -75,3 +77,8 @@ class Response(object_ref):
             kwargs.setdefault(x, getattr(self, x))
         cls = kwargs.pop('cls', self.__class__)
         return cls(*args, **kwargs)
+
+    def urljoin(self, url):
+        """Join this Response's url with a possible relative url to form an
+        absolute interpretation of the latter."""
+        return urljoin(self.url, url)