[Zope3-checkins] SVN: Zope3/trunk/src/zope/app/component/ Added a new `LayerField`, so that we can ensure that layer names are correclty

[Stephan Richter]

Log message for revision 27586:
  
  Added a new `LayerField`, so that we can ensure that layer names are correclty
  converted to interfaces.
  
  


Changed:
  A   Zope3/trunk/src/zope/app/component/fields.py
  A   Zope3/trunk/src/zope/app/component/tests/test_fields.py


-=-
Added: Zope3/trunk/src/zope/app/component/fields.py
===================================================================
--- Zope3/trunk/src/zope/app/component/fields.py	2004-09-17 16:16:08 UTC (rev 27585)
+++ Zope3/trunk/src/zope/app/component/fields.py	2004-09-17 16:16:09 UTC (rev 27586)
@@ -0,0 +1,112 @@
+#############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Corporation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+"""Browser configuration code
+
+This module defines the schemas for browser directives.
+
+$Id: metadirectives.py 26994 2004-08-11 10:07:39Z gintautasm $
+"""
+__docformat__ = 'restructuredtext'
+
+import zope.schema
+from zope.component.exceptions import ComponentLookupError
+from zope.configuration.exceptions import ConfigurationError
+from zope.configuration.fields import GlobalObject
+from zope.interface.interfaces import IInterface
+from zope.publisher.interfaces.browser import ILayer
+
+from zope.app import zapi
+
+
+class LayerField(GlobalObject):
+    r"""This fields represents a layer.
+
+    Besides being able to look up the layer by importing it, we also try
+    to look up the name in the utility service.
+
+    >>> from zope.interface import directlyProvides
+    >>> from zope.interface.interface import InterfaceClass
+
+    >>> layer1 = InterfaceClass('layer1', (),
+    ...                         __doc__='Layer: layer1',
+    ...                         __module__='zope.app.layers')
+    >>> directlyProvides(layer1, ILayer)
+
+    >>> layers = None
+    >>> class Resolver(object):
+    ...     def resolve(self, path):
+    ...         if path.startswith('zope.app.layers') and \
+    ...             hasattr(layers, 'layer1') or \
+    ...             path == 'zope.app.component.fields.layer1':
+    ...             return layer1
+    ...         raise ConfigurationError, 'layer1'
+
+    >>> field = LayerField()
+    >>> field = field.bind(Resolver())
+
+    Test 1: Import the layer
+    ------------------------
+
+    >>> field.fromUnicode('zope.app.component.fields.layer1') is layer1
+    True
+
+    Test 2: We have a shortcut name. Import the layer from `zope.app.layers`.
+    -------------------------------------------------------------------------
+
+    >>> from types import ModuleType as module
+    >>> import sys
+    >>> layers = module('layers')
+    >>> old = sys.modules.get('zope.app.layers', None)
+    >>> sys.modules['zope.app.layers'] = layers
+    >>> setattr(layers, 'layer1', layer1)
+
+    >>> field.fromUnicode('layer1') is layer1
+    True
+
+    >>> if old is not None:
+    ...     sys.modules['zope.app.layers'] = old
+
+    Test 3: Get the layer from the utility service
+    ----------------------------------------------
+    
+    >>> from zope.app.tests import ztapi
+    >>> ztapi.provideUtility(ILayer, layer1, 'layer1')
+
+    >>> field.fromUnicode('layer1') is layer1
+    True
+    """
+
+    def fromUnicode(self, u):
+        name = str(u.strip())
+
+        try:
+            value = zapi.queryUtility(ILayer, name)
+        except ComponentLookupError:
+            # The component architecture is not up and running.
+            pass
+        else: 
+            if value is not None:
+                return value
+
+        try:
+            value = self.context.resolve(name)
+        except ConfigurationError, v:
+            name = 'zope.app.layers.'+name
+            try:
+                value = self.context.resolve(name)
+            except ConfigurationError, v:
+                raise zope.schema.ValidationError(v)
+        
+        self.validate(value)
+        return value

Added: Zope3/trunk/src/zope/app/component/tests/test_fields.py
===================================================================
--- Zope3/trunk/src/zope/app/component/tests/test_fields.py	2004-09-17 16:16:08 UTC (rev 27585)
+++ Zope3/trunk/src/zope/app/component/tests/test_fields.py	2004-09-17 16:16:09 UTC (rev 27586)
@@ -0,0 +1,30 @@
+##############################################################################
+#
+# Copyright (c) 2004 Zope Corporation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+"""Test fields.
+
+$Id$
+"""
+import unittest
+from zope.testing.doctestunit import DocTestSuite
+from zope.app.tests import placelesssetup
+
+def test_suite():
+    return unittest.TestSuite((
+        DocTestSuite('zope.app.component.fields',
+                     setUp=placelesssetup.setUp,
+                     tearDown=placelesssetup.tearDown),
+        ))
+
+if __name__ == '__main__':
+    unittest.main(defaultTest='test_suite')