Add a third-party ReferenceListProperty class. This is going to be used to
authorTodd Larsen <tlarsen@google.com>
Tue, 14 Oct 2008 21:02:28 +0000
changeset 326 4a4474944dee
parent 325 1469eff8f59e
child 327 629cc34e37bf
Add a third-party ReferenceListProperty class. This is going to be used to contain the references to Questions that make up a Quiz. Patch by: Todd Larsen Review by: to-be-reviewed
app/reflistprop/LICENSE
app/reflistprop/__init__.py
scripts/make_release.sh
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/reflistprop/LICENSE	Tue Oct 14 21:02:28 2008 +0000
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/reflistprop/__init__.py	Tue Oct 14 21:02:28 2008 +0000
@@ -0,0 +1,185 @@
+#!/usr/bin/python2.5
+#
+# Copyright 2007 Ken Tidwell 
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License. 
+# You may obtain a copy of the License at 
+#
+#     http://www.apache.org/licenses/LICENSE-2.0 
+#
+# Unless required by applicable law or agreed to in writing, software 
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+# See the License for the specific language governing permissions and 
+# limitations under the License.
+# 
+"""Simple property for storing ordered lists of Model objects.
+
+It should be noted that larger lists are going to be VERY inefficient
+to load (one get per object).
+
+Currently I have no idea where that upper bound might lie, though.
+ 
+A quick usage example:
+        class Bit(db.Model):
+                name = db.StringProperty(required=True)\ 
+        class Holder(db.Model):
+                bits = reflistprop.ReferenceListProperty(Bit, default=None) 
+        b1 = Bit(name="first") 
+        b1.put() # need to put it so that it is a valid reference object 
+        h1 = holder() 
+        h1.bits.append(b1) 
+        h1.put()
+         
+These also work: 
+        h1.bits = [b1]
+         
+This throws a db.BadValueError because a string is not an instance of 
+Bit: 
+        h1.bits = ["nasty evil string"]
+         
+This is not good but gets no complaint at assignment time (same 
+behaviour as ListProperty)
+but we will throw a db.BadValueError if you try to put it into the 
+datastore. (Maybe ListProperty
+wants to do the same? Or should I be waiting for the datastore 
+internal entity construction to
+notice the problem and throw?):
+        h1.bits.append("nasty evil string")
+
+Yes, of course you can query them. The important bit to understand is 
+that the list is stored as a list of keys in the datastore. So you use 
+the key of the entity in question in your query. (Seems like it would be 
+nice if the property could get involved and do that coercion for you but 
+I don't think it can right now...).
+ 
+Here's a little example:
+        class Thang(db.Model): 
+            name = db.StringProperty(required=True) 
+        class Holder(db.Model): 
+            thangs = langutils.ReferenceListProperty(Thang, default=None) 
+        holder1 = Holder() 
+        holder1.put() 
+        foo = Thang(name="foo") 
+        foo.put() 
+        holder1.thangs.append(foo) 
+        holder1.put() 
+        hq = db.GqlQuery("SELECT * FROM Holder where thangs = :1", foo.key()) 
+        holders = hq.fetch(10) 
+        print "Holders =", holders
+        
+Obtained from:
+  http://groups.google.com/group/google-appengine/msg/d203cc1b93ee22d7 
+"""
+
+
+from google.appengine.ext import db
+
+ 
+class ReferenceListProperty(db.Property):
+  """A property that stores a list of models. 
+  This is a parameterized property; the parameter must be a valid 
+  Model type, and all items must conform to this type.
+  """
+  def __init__(self, item_type, verbose_name=None, default=None, **kwds): 
+    """Construct ReferenceListProperty.
+
+    Args:
+      item_type: Type for the list items; must be a subclass of Model. 
+      verbose_name: Optional verbose name.
+      default: Optional default value; if omitted, an empty list is used. 
+      **kwds: Optional additional keyword arguments, passed to base class. 
+    """
+    if not issubclass(item_type, db.Model): 
+      raise TypeError('Item type should be a subclass of Model') 
+    if default is None:
+      default = []
+    self.item_type = item_type 
+    super(ReferenceListProperty, self).__init__(verbose_name, 
+                                                default=default,
+                                                **kwds)
+  def validate(self, value):
+    """Validate list.
+
+    Note that validation here is just as broken as for ListProperty. 
+    The values in the list are only validated if the entire list is
+    swapped out.
+    If the list is directly modified, there is no attempt to validate 
+    the new items.
+
+    Returns:
+      A valid value. 
+
+    Raises:
+      BadValueError if property is not a list whose items are 
+      instances of the item_type given to the constructor.
+    """ 
+    value = super(ReferenceListProperty, self).validate(value) 
+    if value is not None: 
+      if not isinstance(value, list): 
+        raise db.BadValueError('Property %s must be a list' % 
+                               self.name)
+      for item in value:
+        if not isinstance(item, self.item_type): 
+            raise db.BadValueError(
+                'Items in the %s list must all be %s instances' % 
+                (self.name, self.item_type.__name__))
+    return value
+
+  def empty(self, value): 
+    """Is list property empty.
+
+    [] is not an empty value.
+ 
+    Returns:
+      True if value is None, else False. 
+    """ 
+    return value is None
+
+  data_type = list
+ 
+  def default_value(self): 
+    """Default value for list.
+ 
+    Because the property supplied to 'default' is a static value, 
+    that value must be shallow copied to prevent all fields with 
+    default values from sharing the same instance.
+ 
+    Returns: 
+      Copy of the default value. 
+    """ 
+    return list(super(ReferenceListProperty, self).default_value())
+ 
+  def get_value_for_datastore(self, model_instance): 
+    """A list of key values is stored.
+
+    Prior to storage, we validate the items in the list. 
+    This check seems to be missing from ListProperty.
+
+    Args: 
+      model_instance: Instance to fetch datastore value from.
+ 
+    Returns: 
+      A list of the keys for all Models in the value list. 
+    """ 
+    value = self.__get__(model_instance, model_instance.__class__) 
+    self.validate(value) 
+    if value is None: 
+        return None 
+    else: 
+        return [v.key() for v in value]
+ 
+  def make_value_from_datastore(self, value): 
+    """Recreates the list of Models from the list of keys.
+ 
+    Args:
+      value: value retrieved from the datastore entity.
+
+    Returns: 
+      None or a list of Models. 
+    """ 
+    if value is None:
+        return None
+    else:
+        return [db.get(v) for v in value] 
--- a/scripts/make_release.sh	Tue Oct 14 20:33:20 2008 +0000
+++ b/scripts/make_release.sh	Tue Oct 14 21:02:28 2008 +0000
@@ -11,7 +11,7 @@
 DEFAULT_APP_RELEASE=../release
 DEFAULT_APP_FOLDER="../app"
 DEFAULT_APP_FILES="app.yaml index.yaml __init__.py main.py settings.py urls.py"
-DEFAULT_APP_DIRS="soc ghop gsoc feedparser polymodel python25src"
+DEFAULT_APP_DIRS="soc ghop gsoc feedparser polymodel python25src reflistprop"
 DEFAULT_ZIP_FILES="tiny_mce.zip"
 
 APP_RELEASE=${APP_RELEASE:-"${DEFAULT_APP_RELEASE}"}