From 4aa6179af7158393662f13898253bf78849bf2d7 Mon Sep 17 00:00:00 2001
From: Alexander Chekunkov <chekunkov@gmail.com>
Date: Sat, 26 Apr 2014 15:46:53 +0300
Subject: [PATCH] added short RFPDupeFilter.request_fingerprint interface
 description

---
 docs/topics/settings.rst | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/docs/topics/settings.rst b/docs/topics/settings.rst
index 78728ac97..035e12c82 100644
--- a/docs/topics/settings.rst
+++ b/docs/topics/settings.rst
@@ -410,7 +410,9 @@ The class used to detect and filter duplicate requests.
 The default (``RFPDupeFilter``) filters based on request fingerprint using
 the ``scrapy.utils.request.request_fingerprint`` function. In order to change
 the way duplicates are checked you could subclass ``RFPDupeFilter`` and
-override its ``request_fingerprint`` method.
+override its ``request_fingerprint`` method. This method should accept
+scrapy :class:`~scrapy.http.Request` object and return its fingerprint
+(a string).
 
 .. setting:: DUPEFILTER_DEBUG