backwards compatibility support for FeedExport's that don't receive a settings object in their constructor

scrapy/contrib/feedexport.py

@@ -18,6 +18,7 @@ from scrapy import log, signals
 from scrapy.utils.ftp import ftp_makedirs_cwd
 from scrapy.exceptions import NotConfigured
 from scrapy.utils.misc import load_object
+from scrapy.utils.python import get_func_args
 
 
 class IFeedStorage(Interface):
@@ -133,7 +134,6 @@ class SpiderSlot(object):
 class FeedExporter(object):
 
     def __init__(self, settings):
-        self.settings = settings
         self.urifmt = settings['FEED_URI']
         if not self.urifmt:
             raise NotConfigured
@@ -151,7 +151,15 @@ class FeedExporter(object):
 
     @classmethod
     def from_crawler(cls, crawler):
-        o = cls(crawler.settings)
+        if len(get_func_args(cls)) < 1:
+            # FIXME: remove for scrapy 0.17
+            import warnings
+            from scrapy.exceptions import ScrapyDeprecationWarning
+            warnings.warn("%s must receive a settings object as first constructor argument." % cls.__name__,
+                ScrapyDeprecationWarning, stacklevel=2)
+            o = cls()
+        else:
+            o = cls(crawler.settings)
         crawler.signals.connect(o.open_spider, signals.spider_opened)
         crawler.signals.connect(o.close_spider, signals.spider_closed)
         crawler.signals.connect(o.item_scraped, signals.item_scraped)