added COOKIES_ENABLED setting to support disabling the cookies middleware

docs/topics/downloader-middleware.rst

@@ -168,14 +168,26 @@ CookiesMiddleware
 
 .. class:: CookiesMiddleware
 
-   This middleware enables working with sites that need cookies. It keeps track
-   of merging cookies sent by servers, so that they're send in future requests
-   for that spider, just like a web browser would do.
+   This middleware enables working with sites that require cookies, such as
+   those that use sessions. It keeps track of cookies sent by web servers, and
+   send them back on subsequent requests (from that spider), just like web
+   browsers do.
 
 The following settings can be used to configure the cookie middleware:
 
+* :setting:`COOKIES_ENABLED`
 * :setting:`COOKIES_DEBUG`
 
+.. setting:: COOKIES_ENABLED
+
+COOKIES_ENABLED
+~~~~~~~~~~~~~~~
+
+Default: ``True``
+
+Whether to enable the cookies middleware. If disabled, no cookies will be sent
+to web servers.
+
 .. setting:: COOKIES_DEBUG
 
 COOKIES_DEBUG

docs/topics/settings.rst

@@ -261,15 +261,6 @@ Default: ``8``
 
 Maximum number of spiders to scrape in parallel.
 
-.. setting:: COOKIES_DEBUG
-
-COOKIES_DEBUG
--------------
-
-Default: ``False``
-
-Enable debugging message of Cookies Downloader Middleware.
-
 .. setting:: DEFAULT_ITEM_CLASS
 
 DEFAULT_ITEM_CLASS

scrapy/contrib/downloadermiddleware/cookies.py

@@ -3,6 +3,7 @@ from collections import defaultdict
 from scrapy.xlib.pydispatch import dispatcher
 
 from scrapy import signals
+from scrapy.exceptions import NotConfigured
 from scrapy.http import Response
 from scrapy.http.cookies import CookieJar
 from scrapy.conf import settings
@@ -14,6 +15,8 @@ class CookiesMiddleware(object):
     debug = settings.getbool('COOKIES_DEBUG')
 
     def __init__(self):
+        if not settings.getbool('COOKIES_ENABLED'):
+            raise NotConfigured
         self.jars = defaultdict(CookieJar)
         dispatcher.connect(self.spider_closed, signals.spider_closed)
 

scrapy/settings/default_settings.py

@@ -28,6 +28,7 @@ CONCURRENT_ITEMS = 100
 CONCURRENT_REQUESTS_PER_SPIDER = 8
 CONCURRENT_SPIDERS = 8
 
+COOKIES_ENABLED = True
 COOKIES_DEBUG = False
 
 DEFAULT_ITEM_CLASS = 'scrapy.item.Item'