Configure StickyMetaParamsMiddleware from settings

Configure middleware through settings instead of a spider attribute.

docs/topics/settings.rst

@@ -1383,6 +1383,16 @@ Default: ``[]`` (empty list)
 Send Scrapy stats after spiders finish scraping. See
 :class:`~scrapy.extensions.statsmailer.StatsMailer` for more info.
 
+.. setting:: STICKY_META_KEYS
+
+STICKY_META_KEYS
+----------------
+
+Default: ``[]`` (empty list)
+
+Configure which key/values should be stickied in :attr:`Request.meta`. See
+:class:`~scrapy.spidermiddlewares.stickymeta.StickyMetaParamsMiddleware` for more info.
+
 .. setting:: TELNETCONSOLE_ENABLED
 
 TELNETCONSOLE_ENABLED

docs/topics/spider-middleware.rst

@@ -463,8 +463,7 @@ StickyMetaParamsMiddleware
    When enabled and configured, this middleware forwards the desired :ref:`Request.meta <topics-request-meta>`
    parameters between ``Requests`` and ``Responses``.
 
-   The :class:`StickyMetaParamsMiddleware` can be configured through the :attr:`~scrapy.spiders.Spider.sticky_meta_keys`
-   spider attribute.
+   The :class:`StickyMetaParamsMiddleware` can be configured through the settings :setting:`STICKY_META_KEYS`.
 
    See the difference between :ref:`topics-spiders` with and without the middleware:
 
@@ -505,7 +504,7 @@ StickyMetaParamsMiddleware
     class StickySpider(Spider):
         name = 'sticky'
         start_urls = ['https://www.example.com']
-        sticky_meta_keys = ['param']  # Will always forward the meta param "param"
+        custom_settings = {'STICKY_META_KEYS': ['param']}  # Will always forward the meta param "param"
 
         def parse(self, response):
             for param in range(5):

docs/topics/spiders.rst

@@ -196,13 +196,6 @@ scrapy.Spider
        Called when the spider closes. This method provides a shortcut to
        signals.connect() for the :signal:`spider_closed` signal.
 
-   .. attribute:: sticky_meta_keys
-
-      Keys to be stickied in ``meta`` dictionary.
-
-      For more information about stickied meta parameters see:
-      :class:`~scrapy.spidermiddlewares.stickymeta.StickyMetaParamsMiddleware`
-
 Let's see an example::
 
     import scrapy

scrapy/spidermiddlewares/stickymeta.py

@@ -7,7 +7,7 @@ class StickyMetaParamsMiddleware(object):
 
     @classmethod
     def from_crawler(cls, crawler):
-        keys_to_sticky = getattr(crawler.spider, 'sticky_meta_keys', [])
+        keys_to_sticky = crawler.settings.get('STICKY_META_KEYS', [])
         if not keys_to_sticky:
             raise NotConfigured
         return cls(keys_to_sticky)

scrapy/spiders/__init__.py

@@ -20,7 +20,6 @@ class Spider(object_ref):
 
     name = None
     custom_settings = None
-    sticky_meta_keys = []
 
     def __init__(self, name=None, **kwargs):
         if name is not None:

tests/test_spidermiddleware_stickymeta.py

@@ -22,21 +22,13 @@ class TestStickyMetaParamsMiddleware(TestCase):
     def create_middleware(self, crawler):
         return StickyMetaParamsMiddleware.from_crawler(crawler)
 
-    def _get_crawler(self, spider):
-        crawler = get_crawler(Spider)
-        crawler.spider = spider
-        return crawler
-
     def test_middleware_not_enabled(self):
-        spider = Spider('dummy')
-        crawler = self._get_crawler(spider)
+        crawler = get_crawler(Spider)
         with pytest.raises(NotConfigured):
             self.create_middleware(crawler)
 
     def test_sticky_params(self):
-        spider = Spider('dummy')
-        spider.sticky_meta_keys = ['param2']
-        crawler = self._get_crawler(spider)
+        crawler = get_crawler(Spider, {'STICKY_META_KEYS': ['param2']})
         middleware = self.create_middleware(crawler)
         request = Request(
             self.test_url,
@@ -49,7 +41,7 @@ class TestStickyMetaParamsMiddleware(TestCase):
             Request(self.test_url),
             MockItem(name='dummy')
         ]
-        results = middleware.process_spider_output(response, result, spider)
+        results = middleware.process_spider_output(response, result, None)
         for result in results:
             if isinstance(result, Request):
                 self.assertEqual(result.meta, {'param2': 'Stickied!'})