replaced UsageError exception by more standard (and explicit) ones such as TypeError and ValueError

--HG--
extra : convert_revision : svn%3Ab85faa78-f9eb-468e-a121-7cced6da292c%40936

scrapy/trunk/scrapy/contrib/item/models.py

@@ -5,19 +5,16 @@ useful in some Scrapy implementations
 
 import hashlib
 
-from pydispatch import dispatcher
 from pprint import PrettyPrinter
 
 from scrapy.item import ScrapedItem, ItemDelta
 from scrapy.item.adaptors import AdaptorPipe
-from scrapy.spider import spiders
-from scrapy.core import signals
-from scrapy.core.exceptions import UsageError, DropItem
+from scrapy.core.exceptions import DropItem
 from scrapy.utils.python import unique
 
 class ValidationError(DropItem):
     """Indicates a data validation error"""
-    def __init__(self,problem,value=None):
+    def __init__(self, problem, value=None):
         self.problem = problem
         self.value = value
 
@@ -141,7 +138,7 @@ class RobustScrapedItem(ScrapedItem):
             return ret
 
         if not values:
-            raise UsageError("You must specify at least one value when setting an attribute")
+            raise ValueError("You must specify at least one value when setting an attribute")
         if attrname not in self.ATTRIBUTES:
             raise AttributeError('Attribute "%s" is not a valid attribute name. You must add it to %s.ATTRIBUTES' % (attrname, self.__class__.__name__))
 
@@ -215,7 +212,7 @@ class RobustScrapedItem(ScrapedItem):
         if getattr(self, '_version', None):
             return self._version
         hash_ = hashlib.sha1()
-        hash_.update("".join(["".join([n, str(v)]) for n,v in sorted(self.__dict__.iteritems())]))
+        hash_.update("".join(["".join([n, str(v)]) for n, v in sorted(self.__dict__.iteritems())]))
         return hash_.hexdigest()
 
 

scrapy/trunk/scrapy/contrib/spiders/feed.py

@@ -10,7 +10,7 @@ from scrapy.item import ScrapedItem
 from scrapy.http import Request
 from scrapy.utils.iterators import xmliter, csviter
 from scrapy.xpath.selector import XmlXPathSelector, HtmlXPathSelector
-from scrapy.core.exceptions import UsageError, NotConfigured, NotSupported
+from scrapy.core.exceptions import NotConfigured, NotSupported
 
 class XMLFeedSpider(BaseSpider):
     """
@@ -55,7 +55,7 @@ class XMLFeedSpider(BaseSpider):
             if isinstance(ret, (ScrapedItem, Request)):
                 ret = [ret]
             if not isinstance(ret, (list, tuple)):
-                raise UsageError('You cannot return an "%s" object from a spider' % type(ret).__name__)
+                raise TypeError('You cannot return an "%s" object from a spider' % type(ret).__name__)
             for result_item in self.process_results(response, ret):
                 yield result_item
 
@@ -107,7 +107,7 @@ class CSVFeedSpider(BaseSpider):
             if isinstance(ret, (ScrapedItem, Request)):
                 ret = [ret]
             if not isinstance(ret, (list, tuple)):
-                raise UsageError('You cannot return an "%s" object from a spider' % type(ret).__name__)
+                raise TypeError('You cannot return an "%s" object from a spider' % type(ret).__name__)
             for result_item in self.process_results(response, ret):
                 yield result_item
 

scrapy/trunk/scrapy/core/downloader/handlers.py

@@ -3,10 +3,9 @@ Download handlers for different schemes
 """
 from __future__ import with_statement
 
-import os
 import urlparse
 
-from twisted.internet import defer, reactor
+from twisted.internet import reactor
 from twisted.web import error as web_error
 
 try:
@@ -16,8 +15,8 @@ except ImportError:
 
 from scrapy import optional_features
 from scrapy.core import signals
-from scrapy.http import Request, Response, Headers
-from scrapy.core.exceptions import UsageError, HttpException, NotSupported
+from scrapy.http import Headers
+from scrapy.core.exceptions import HttpException, NotSupported
 from scrapy.utils.defer import defer_succeed
 from scrapy.conf import settings
 

scrapy/trunk/scrapy/core/exceptions.py

@@ -7,10 +7,6 @@ new exceptions here without documenting them there.
 
 # Internal
 
-class UsageError(Exception):
-    """Incorrect usage of the core API"""
-    pass
-
 class NotConfigured(Exception):
     """Indicates a missing configuration situation"""
     pass

scrapy/trunk/scrapy/spider/models.py

@@ -8,20 +8,19 @@ from twisted.plugin import IPlugin
 
 from scrapy import log
 from scrapy.http import Request
-from scrapy.core.exceptions import UsageError
 
 def _valid_domain_name(obj):
     """Check the domain name specified is valid"""
     if not obj.domain_name:
-        raise UsageError("A site domain name is required")
+        raise ValueError("A site domain name is required")
 
 def _valid_download_delay(obj):
     """Check the download delay is valid, if specified"""
     delay = getattr(obj, 'download_delay', 0)
     if not type(delay) in (int, long, float):
-        raise UsageError("download_delay must be numeric")
+        raise ValueError("download_delay must be numeric")
     if float(delay) < 0.0:
-        raise UsageError("download_delay must be positive")
+        raise ValueError("download_delay must be positive")
 
 class ISpider(Interface, IPlugin) :
     """Interface to be implemented by site-specific web spiders"""

scrapy/trunk/scrapy/tests/test_robustscrapeditem.py

@@ -2,9 +2,8 @@
 import unittest
 
 from scrapy.contrib.item import RobustScrapedItem
-from scrapy.item.adaptors import AdaptorPipe, AdaptorFunc
+from scrapy.item.adaptors import AdaptorPipe
 from scrapy.contrib_exp import adaptors
-from scrapy.core.exceptions import UsageError
 
 class MyItem(RobustScrapedItem):
     ATTRIBUTES = {
@@ -20,7 +19,7 @@ class RobustScrapedItemTestCase(unittest.TestCase):
         self.item = MyItem()
 
     def test_attribute_basic(self):
-        self.assertRaises(UsageError, self.item.attribute, 'foo')
+        self.assertRaises(ValueError, self.item.attribute, 'foo')
         self.assertRaises(AttributeError, self.item.attribute, 'foo', 'something')
 
         self.item.attribute('name', 'John')

scrapy/trunk/scrapy/tests/test_utils_misc.py

@@ -2,7 +2,6 @@ import unittest
 from cStringIO import StringIO
 
 from scrapy.utils.misc import hash_values, items_to_csv, load_object, to_list
-from scrapy.core.exceptions import UsageError
 from scrapy.item import ScrapedItem
 
 class UtilsMiscTestCase(unittest.TestCase):
@@ -10,7 +9,7 @@ class UtilsMiscTestCase(unittest.TestCase):
         self.assertEqual(hash_values('some', 'values', 'to', 'hash'),
                          'f37f5dc65beaaea35af05e16e26d439fd150c576')
 
-        self.assertRaises(UsageError, hash_values, 'some', None, 'value')
+        self.assertRaises(ValueError, hash_values, 'some', None, 'value')
 
     def test_items_to_csv(self):
         item_1 = ScrapedItem()
@@ -59,6 +58,8 @@ class UtilsMiscTestCase(unittest.TestCase):
     def test_load_object(self):
         obj = load_object('scrapy.utils.misc.load_object')
         assert obj is load_object
+        self.assertRaises(ImportError, load_object, 'nomodule999.mod.function')
+        self.assertRaises(NameError, load_object, 'scrapy.utils.misc.load_object999')
 
     def test_to_list(self):
         self.assertEqual(to_list(None), [])

scrapy/trunk/scrapy/utils/misc.py

@@ -10,7 +10,6 @@ import csv
 
 from twisted.internet import defer
 
-from scrapy.core.exceptions import UsageError
 from scrapy.utils.python import flatten, unicode_to_str
 from scrapy.utils.markup import remove_entities
 from scrapy.utils.defer import defer_succeed
@@ -78,18 +77,18 @@ def load_object(path):
     try:
         dot = path.rindex('.')
     except ValueError:
-        raise UsageError, '%s isn\'t a module' % path
+        raise ValueError, "Error loading object '%s': not a full path" % path
 
     module, name = path[:dot], path[dot+1:]
     try:
         mod = __import__(module, {}, {}, [''])
     except ImportError, e:
-        raise UsageError, 'Error importing %s: "%s"' % (module, e)
+        raise ImportError, "Error loading object '%s': %s" % (path, e)
 
     try:
         obj = getattr(mod, name)
     except AttributeError:
-        raise UsageError, 'module "%s" does not define any object named "%s"' % (module, name)
+        raise NameError, "Module '%s' doesn't define any object named '%s'" % (module, name)
 
     return obj
 load_class = load_object # backwards compatibility, but isnt going to be available for too long.
@@ -117,7 +116,7 @@ def extract_regex(regex, text, encoding):
         return [remove_entities(unicode(s, encoding), keep=['lt', 'amp']) for s in strings]
 
 def hash_values(*values):
-    """Hash a series of values. 
+    """Hash a series of non-None values. 
     
     For example:
     >>> hash_values('some', 'values', 'to', 'hash')
@@ -126,9 +125,8 @@ def hash_values(*values):
     hash = hashlib.sha1()
     for value in values:
         if value is None:
-            message = "hash_values was passed None at argument index %d. This is a bug in the calling code" \
-                    % list(values).index(None)
-            raise UsageError(message)
+            message = "hash_values was passed None at argument index %d" % list(values).index(None)
+            raise ValueError(message)
         hash.update(value)
     return hash.hexdigest()