Move property subclasses snippets from cloudsite.

Author: Jerjou Cheng

appengine/ndb/property_subclasses/README.md

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+## App Engine Datastore NDB Property Subclasses Samples
+
+This contains snippets used in the NDB property subclasses documentation,
+demonstrating various operation on ndb property subclasses.
+
+<!-- auto-doc-link -->
+These samples are used on the following documentation page:
+
+> https://cloud.google.com/appengine/docs/python/ndb/subclassprop
+
+<!-- end-auto-doc-link -->

appengine/ndb/property_subclasses/my_models.py

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+# Copyright 2016 Google Inc. All rights reserved.
+#
+# 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.
+
+from datetime import date
+
+from google.appengine.ext import ndb
+
+
+class LongIntegerProperty(ndb.StringProperty):
+    def _validate(self, value):
+        if not isinstance(value, (int, long)):
+            raise TypeError('expected an integer, got %s' % repr(value))
+
+    def _to_base_type(self, value):
+        return str(value)  # Doesn't matter if it's an int or a long
+
+    def _from_base_type(self, value):
+        return long(value)  # Always return a long
+
+
+class BoundedLongIntegerProperty(ndb.StringProperty):
+    def __init__(self, bits, **kwds):
+        assert isinstance(bits, int)
+        assert bits > 0 and bits % 4 == 0  # Make it simple to use hex
+        super(BoundedLongIntegerProperty, self).__init__(**kwds)
+        self._bits = bits
+
+    def _validate(self, value):
+        assert -(2 ** (self._bits - 1)) <= value < 2 ** (self._bits - 1)
+
+    def _to_base_type(self, value):
+        # convert from signed -> unsigned
+        if value < 0:
+            value += 2 ** self._bits
+        assert 0 <= value < 2 ** self._bits
+        # Return number as a zero-padded hex string with correct number of
+        # digits:
+        return '%0*x' % (self._bits // 4, value)
+
+    def _from_base_type(self, value):
+        value = int(value, 16)
+        if value >= 2 ** (self._bits - 1):
+            value -= 2 ** self._bits
+        return value
+
+
+# Define an entity class holding some long integers.
+class MyModel(ndb.Model):
+    name = ndb.StringProperty()
+    abc = LongIntegerProperty(default=0)
+    xyz = LongIntegerProperty(repeated=True)
+
+
+class FuzzyDate(object):
+    def __init__(self, first, last=None):
+        assert isinstance(first, date)
+        assert last is None or isinstance(last, date)
+        self.first = first
+        self.last = last or first
+
+
+class FuzzyDateModel(ndb.Model):
+    first = ndb.DateProperty()
+    last = ndb.DateProperty()
+
+
+class FuzzyDateProperty(ndb.StructuredProperty):
+    def __init__(self, **kwds):
+        super(FuzzyDateProperty, self).__init__(FuzzyDateModel, **kwds)
+
+    def _validate(self, value):
+        assert isinstance(value, FuzzyDate)
+
+    def _to_base_type(self, value):
+        return FuzzyDateModel(first=value.first, last=value.last)
+
+    def _from_base_type(self, value):
+        return FuzzyDate(value.first, value.last)
+
+
+class MaybeFuzzyDateProperty(FuzzyDateProperty):
+    def _validate(self, value):
+        if isinstance(value, date):
+            return FuzzyDate(value)  # Must return the converted value!
+        # Otherwise, return None and leave validation to the base class
+
+
+# Class to record historic people and events in their life.
+class HistoricPerson(ndb.Model):
+    name = ndb.StringProperty()
+    birth = FuzzyDateProperty()
+    death = FuzzyDateProperty()
+    # Parallel lists:
+    event_dates = FuzzyDateProperty(repeated=True)
+    event_names = ndb.StringProperty(repeated=True)

appengine/ndb/property_subclasses/snippets.py

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+# Copyright 2016 Google Inc. All rights reserved.
+#
+# 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.
+
+from datetime import date
+
+import my_models
+
+
+def create_entity():
+    # Create an entity and write it to the Datastore.
+    entity = my_models.MyModel(name='booh', xyz=[10**100, 6**666])
+    assert entity.abc == 0
+    key = entity.put()
+    return key
+
+
+def read_and_update_entity(key):
+    # Read an entity back from the Datastore and update it.
+    entity = key.get()
+    entity.abc += 1
+    entity.xyz.append(entity.abc//3)
+    entity.put()
+
+
+def query_entity():
+    # Query for a MyModel entity whose xyz contains 6**666.
+    # (NOTE: using ordering operations don't work, but == does.)
+    results = my_models.MyModel.query(
+        my_models.MyModel.xyz == 6**666).fetch(10)
+    return results
+
+
+def create_and_query_columbus():
+    columbus = my_models.HistoricPerson(
+        name='Christopher Columbus',
+        birth=my_models.FuzzyDate(date(1451, 8, 22), date(1451, 10, 31)),
+        death=my_models.FuzzyDate(date(1506, 5, 20)),
+        event_dates=[my_models.FuzzyDate(
+            date(1492, 1, 1), date(1492, 12, 31))],
+        event_names=['Discovery of America'])
+    columbus.put()
+
+    # Query for historic people born no later than 1451.
+    results = my_models.HistoricPerson.query(
+        my_models.HistoricPerson.birth.last <= date(1451, 12, 31)).fetch()
+    return results

appengine/ndb/property_subclasses/snippets_test.py

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+# Copyright 2016 Google Inc. All rights reserved.
+#
+# 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.
+
+import datetime
+
+from google.appengine.ext import ndb
+import my_models
+import pytest
+import snippets
+
+
+def test_create_entity(testbed):
+    assert my_models.MyModel.query().count() == 0
+    snippets.create_entity()
+    entities = my_models.MyModel.query().fetch()
+    assert len(entities) == 1
+    assert entities[0].name == 'booh'
+
+
+def test_read_and_update_entity(testbed):
+    key = snippets.create_entity()
+    entities = my_models.MyModel.query().fetch()
+    assert len(entities) == 1
+    assert entities[0].abc == 0
+    len_xyz = len(entities[0].xyz)
+
+    snippets.read_and_update_entity(key)
+    entities = my_models.MyModel.query().fetch()
+    assert len(entities) == 1
+    assert entities[0].abc == 1
+    assert len(entities[0].xyz) == len_xyz + 1
+
+
+def test_query_entity(testbed):
+    results = snippets.query_entity()
+    assert len(results) == 0
+
+    snippets.create_entity()
+    results = snippets.query_entity()
+    assert len(results) == 1
+
+
+def test_create_columbus(testbed):
+    entities = snippets.create_and_query_columbus()
+    assert len(entities) == 1
+    assert entities[0].name == 'Christopher Columbus'
+    assert (entities[0].birth.first < entities[0].birth.last <
+            entities[0].death.first)
+
+
+def test_long_integer_property(testbed):
+    with pytest.raises(TypeError):
+        my_models.MyModel(
+            name='not integer test',
+            xyz=['not integer'])
+
+
+def test_bounded_long_integer_property(testbed):
+    class TestBoundedLongIntegerProperty(ndb.Model):
+        num = my_models.BoundedLongIntegerProperty(4)
+
+    # Test out of the bounds
+    with pytest.raises(AssertionError):
+        TestBoundedLongIntegerProperty(num=0xF)
+    with pytest.raises(AssertionError):
+        TestBoundedLongIntegerProperty(num=-0xF)
+
+    # This should work
+    working_instance = TestBoundedLongIntegerProperty(num=0b111)
+    assert working_instance.num == 0b111
+    working_instance.num = 0b10
+    assert working_instance.num == 2
+
+
+def test_maybe_fuzzy_date_property(testbed):
+    class TestMaybeFuzzyDateProperty(ndb.Model):
+        first_date = my_models.MaybeFuzzyDateProperty()
+        second_date = my_models.MaybeFuzzyDateProperty()
+
+    two_types_of_dates = TestMaybeFuzzyDateProperty(
+        first_date=my_models.FuzzyDate(
+            datetime.date(1984, 2, 27), datetime.date(1984, 2, 29)),
+        second_date=datetime.date(2015, 6, 27))
+
+    assert isinstance(two_types_of_dates.first_date, my_models.FuzzyDate)
+    assert isinstance(two_types_of_dates.second_date, my_models.FuzzyDate)