Added ISpiderManager interface and a test to verify the default Spide…

…rManager comforms to it

scrapy/commands/parse.py

@@ -2,7 +2,7 @@
 from scrapy.http import Request
 from scrapy.item import BaseItem
 from scrapy.utils import display
-from scrapy.utils.spider import iterate_spider_output
+from scrapy.utils.spider import iterate_spider_output, create_spider_for_request
 from scrapy.utils.url import is_url
 from scrapy.exceptions import UsageError
 from scrapy import log
@@ -73,7 +73,7 @@ def get_spider(self, request, opts):
             except KeyError:
                 log.msg('Unable to find spider: %s' % opts.spider, log.ERROR)
         else:
-            spider = self.crawler.spiders.create_for_request(request)
+            spider = create_spider_for_request(self.crawler.spiders, request)
             if spider:
                 return spider
             log.msg('Unable to find spider for: %s' % request, log.ERROR)

scrapy/interfaces.py

@@ -33,3 +33,20 @@ def clear():
         """Clear the queue.
 
         This method can return a deferred. """
+
+class ISpiderManager(Interface):
+
+    def from_settings(settings):
+        """Class method to instantiate from settings"""
+
+    def create(spider_name, **spider_args):
+        """Returns a new Spider instance for the given spider name, and using
+        the given spider arguments. If the spider name is not found, it must
+        raise a KeyError."""
+
+    def list():
+        """Return a list with the names of all spiders available in the
+        project"""
+
+    def find_by_request(request):
+        """Returns the list of spiders names that can handle the given request"""

scrapy/queue.py

@@ -2,6 +2,7 @@
 
 from scrapy.http import Request
 from scrapy.utils.misc import arg_to_iter
+from scrapy.utils.spider import create_spider_for_request
 from scrapy import log
 
 
@@ -58,7 +59,7 @@ def append_spider(self, spider):
 
     def append_request(self, request, spider=None, **kwargs):
         if spider is None:
-            spider = self._spiders.create_for_request(request, **kwargs)
+            spider = create_spider_for_request(self._spiders, request, **kwargs)
         if spider:
             self.spider_requests.append((spider, [request]))
 
@@ -69,7 +70,8 @@ def append_url(self, url=None, spider=None, **kwargs):
         if url is None:
             raise ValueError("A url is required")
         if spider is None:
-            spider = self._spiders.create_for_request(Request(url), **kwargs)
+            spider = create_spider_for_request(self._spiders, Request(url), \
+                **kwargs)
         if spider:
             requests = arg_to_iter(spider.make_requests_from_url(url))
             self.spider_requests.append((spider, requests))

scrapy/shell.py

@@ -13,6 +13,7 @@
 from scrapy.item import BaseItem
 from scrapy.spider import BaseSpider
 from scrapy.selector import XPathSelector, XmlXPathSelector, HtmlXPathSelector
+from scrapy.utils.spider import create_spider_for_request
 from scrapy.utils.misc import load_object
 from scrapy.utils.response import open_in_browser
 from scrapy.utils.url import any_to_uri
@@ -58,7 +59,7 @@ def fetch(self, request_or_url, spider=None):
             url = any_to_uri(request_or_url)
             request = Request(url, dont_filter=True)
         if spider is None:
-            spider = self.crawler.spiders.create_for_request(request, \
+            spider = create_spider_for_request(self.crawler.spiders, request, \
                 BaseSpider('default'), log_multiple=True)
         self.crawler.engine.open_spider(spider)
         response = None

scrapy/spidermanager.py

@@ -3,14 +3,19 @@
 spiders
 """
 
+from zope.interface import implements
+
 from scrapy import log, signals
+from scrapy.interfaces import ISpiderManager
 from scrapy.utils.misc import walk_modules
 from scrapy.utils.spider import iter_spider_classes
 from scrapy.xlib.pydispatch import dispatcher
 
 
 class SpiderManager(object):
 
+    implements(ISpiderManager)
+
     def __init__(self, spider_modules):
         self.spider_modules = spider_modules
         self._spiders = {}
@@ -28,41 +33,13 @@ def from_settings(cls, settings):
         return cls(settings.getlist('SPIDER_MODULES'))
 
     def create(self, spider_name, **spider_kwargs):
-        """Returns a Spider instance for the given spider name, using the given
-        spider arguments. If the spider name is not found, it raises a
-        KeyError.
-        """
         return self._spiders[spider_name](**spider_kwargs)
 
     def find_by_request(self, request):
-        """Returns list of spiders names that match the given Request"""
         return [name for name, cls in self._spiders.iteritems()
-                if cls.handles_request(request)]
-
-    def create_for_request(self, request, default_spider=None, \
-            log_none=False, log_multiple=False, **spider_kwargs):
-        """Create a spider to handle the given Request.
-
-        This will look for the spiders that can handle the given request (using
-        find_by_request) and return a (new) Spider if (and only if) there is
-        only one Spider able to handle the Request.
-
-        If multiple spiders (or no spider) are found, it will return the
-        default_spider passed. It can optionally log if multiple or no spiders
-        are found.
-        """
-        snames = self.find_by_request(request)
-        if len(snames) == 1:
-            return self.create(snames[0], **spider_kwargs)
-        if len(snames) > 1 and log_multiple:
-            log.msg('More than one spider can handle: %s - %s' % \
-                (request, ", ".join(snames)), log.ERROR)
-        if len(snames) == 0 and log_none:
-            log.msg('Unable to find spider that handles: %s' % request, log.ERROR)
-        return default_spider
+            if cls.handles_request(request)]
 
     def list(self):
-        """Returns list of spiders available."""
         return self._spiders.keys()
 
     def close_spider(self, spider, reason):

scrapy/spiderqueue.py

@@ -1,5 +1,4 @@
 from zope.interface import implements
-from zope.interface.verify import verifyObject
 
 from scrapy.interfaces import ISpiderQueue
 from scrapy.utils.sqlite import JsonSqlitePriorityQueue

scrapy/tests/test_queue.py

@@ -18,8 +18,8 @@ def make_requests_from_url(self, url):
 
 class TestSpiderManager(object):
 
-    def create_for_request(self, request, **kwargs):
-        return TestSpider('create_for_request', **kwargs)
+    def find_by_request(self, request):
+        return ['create_for_request']
 
     def create(self, spider_name, **spider_kwargs):
         return TestSpider(spider_name, **spider_kwargs)

scrapy/tests/test_spidermanager/__init__.py

@@ -3,11 +3,14 @@
 import weakref
 import shutil
 
+from zope.interface.verify import verifyObject
 from twisted.trial import unittest
 
+
 # ugly hack to avoid cyclic imports of scrapy.spider when running this test
 # alone
 import scrapy.spider
+from scrapy.interfaces import ISpiderManager
 from scrapy.spidermanager import SpiderManager
 from scrapy.http import Request
 
@@ -28,6 +31,9 @@ def tearDown(self):
         del self.spiderman
         sys.path.remove(self.tmpdir)
 
+    def test_interface(self):
+        verifyObject(ISpiderManager, self.spiderman)
+
     def test_list(self):
         self.assertEqual(set(self.spiderman.list()),
             set(['spider1', 'spider2', 'spider3']))

scrapy/utils/spider.py

@@ -1,5 +1,6 @@
 import inspect
 
+from scrapy import log
 from scrapy.item import BaseItem
 from scrapy.utils.misc import  arg_to_iter
 
@@ -21,3 +22,26 @@ def iter_spider_classes(module):
            obj.__module__ == module.__name__ and \
            getattr(obj, 'name', None):
             yield obj
+
+def create_spider_for_request(spidermanager, request, default_spider=None, \
+        log_none=False, log_multiple=False, **spider_kwargs):
+    """Create a spider to handle the given Request.
+
+    This will look for the spiders that can handle the given request (using
+    the spider manager) and return a (new) Spider if (and only if) there is
+    only one Spider able to handle the Request.
+
+    If multiple spiders (or no spider) are found, it will return the
+    default_spider passed. It can optionally log if multiple or no spiders
+    are found.
+    """
+    snames = spidermanager.find_by_request(request)
+    if len(snames) == 1:
+        return spidermanager.create(snames[0], **spider_kwargs)
+    if len(snames) > 1 and log_multiple:
+        log.msg('More than one spider can handle: %s - %s' % \
+            (request, ", ".join(snames)), log.ERROR)
+    if len(snames) == 0 and log_none:
+        log.msg('Unable to find spider that handles: %s' % request, log.ERROR)
+    return default_spider
+