Move in ndb queries code snippets & test.

GoogleCloudPlatform · Apr 28, 2016 · 91065a3 · 91065a3
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diff --git a/appengine/ndb/queries/README.md b/appengine/ndb/queries/README.md
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+## App Engine Datastore NDB Queries Samples
+
+This contains snippets used in the NDB queries documentation, demonstrating
+various ways to make ndb queries.
+
+<!-- auto-doc-link -->
+These samples are used on the following documentation page:
+
+> https://cloud.google.com/appengine/docs/python/ndb/queries
+
+<!-- end-auto-doc-link -->
diff --git a/appengine/ndb/queries/guestbook.py b/appengine/ndb/queries/guestbook.py
@@ -0,0 +1,75 @@
+# 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 cgi
+
+from google.appengine.datastore.datastore_query import Cursor
+from google.appengine.ext import ndb
+import webapp2
+
+
+class Greeting(ndb.Model):
+    """Models an individual Guestbook entry with content and date."""
+    content = ndb.StringProperty()
+    date = ndb.DateTimeProperty(auto_now_add=True)
+
+    @classmethod
+    def query_book(cls, ancestor_key):
+        return cls.query(ancestor=ancestor_key).order(-cls.date)
+
+
+class MainPage(webapp2.RequestHandler):
+    GREETINGS_PER_PAGE = 20
+
+    def get(self):
+        guestbook_name = self.request.get('guestbook_name')
+        ancestor_key = ndb.Key('Book', guestbook_name or '*notitle*')
+        greetings = Greeting.query_book(ancestor_key).fetch(
+            self.GREETINGS_PER_PAGE)
+
+        self.response.out.write('<html><body>')
+
+        for greeting in greetings:
+            self.response.out.write(
+                '<blockquote>%s</blockquote>' % cgi.escape(greeting.content))
+
+        self.response.out.write('</body></html>')
+
+
+class List(webapp2.RequestHandler):
+    GREETINGS_PER_PAGE = 10
+
+    def get(self):
+        """Handles requests like /list?cursor=1234567."""
+        cursor = Cursor(urlsafe=self.request.get('cursor'))
+        greets, next_cursor, more = Greeting.query().fetch_page(
+            self.GREETINGS_PER_PAGE, start_cursor=cursor)
+
+        self.response.out.write('<html><body>')
+
+        for greeting in greets:
+            self.response.out.write(
+                '<blockquote>%s</blockquote>' % cgi.escape(greeting.content))
+
+        if more and next_cursor:
+            self.response.out.write('<a href="/list?cursor=%s">More...</a>' %
+                                    next_cursor.urlsafe())
+
+        self.response.out.write('</body></html>')
+
+
+app = webapp2.WSGIApplication([
+    ('/', MainPage),
+    ('/list', List),
+], debug=True)
diff --git a/appengine/ndb/queries/guestbook_test.py b/appengine/ndb/queries/guestbook_test.py
@@ -0,0 +1,66 @@
+# 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 re
+
+from google.appengine.ext import ndb
+import guestbook
+import pytest
+import webtest
+
+
+@pytest.fixture
+def app(testbed):
+    return webtest.TestApp(guestbook.app)
+
+
+def test_main(app):
+    # Add a greeting to find
+    guestbook.Greeting(
+        content='Hello world',
+        parent=ndb.Key('Book', 'brane3')).put()
+
+    # Add a greeting to not find.
+    guestbook.Greeting(
+        content='Flat sheet',
+        parent=ndb.Key('Book', 'brane2')).put()
+
+    response = app.get('/?guestbook_name=brane3')
+
+    assert response.status_int == 200
+    assert 'Hello world' in response.body
+    assert 'Flat sheet' not in response.body
+
+
+def test_list(app):
+    # Add greetings to find
+    for i in range(11):
+        guestbook.Greeting(content='Greeting {}'.format(i)).put()
+
+    response = app.get('/list')
+    assert response.status_int == 200
+
+    assert 'Greeting 0' in response.body
+    assert 'Greeting 9' in response.body
+    assert 'Greeting 10' not in response.body
+
+    next_page = re.search(r'href="([^"]+)"', response.body).group(1)
+    assert next_page is not None
+
+    response = app.get(next_page)
+    assert response.status_int == 200
+
+    assert 'Greeting 0' not in response.body
+    assert 'Greeting 10' in response.body
+    assert 'More' not in response.body
diff --git a/appengine/ndb/queries/snippets.py b/appengine/ndb/queries/snippets.py
@@ -0,0 +1,234 @@
+# 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 google.appengine.ext import ndb
+from guestbook import Greeting
+from snippets_models import *  # noqa
+
+
+def query_account_equality():
+    query = Account.query(Account.userid == 42)
+    return query
+
+
+def query_account_inequality():
+    query = Account.query(Account.userid >= 40)
+    return query
+
+
+def query_account_multiple_filters():
+    query = Account.query(Account.userid >= 40, Account.userid < 50)
+    return query
+
+
+def query_account_in_steps():
+    query1 = Account.query()  # Retrieve all Account entitites
+    query2 = query1.filter(Account.userid >= 40)  # Filter on userid >= 40
+    query3 = query2.filter(Account.userid < 50)  # Filter on userid < 50 too
+    return query1, query2, query3
+
+
+def query_article_inequality():
+    query = Article.query(Article.tags != 'perl')
+    return query
+
+
+def query_article_inequality_explicit():
+    query = Article.query(ndb.OR(Article.tags < 'perl',
+                                 Article.tags > 'perl'))
+    return query
+
+
+def articles_with_tags_example():
+    # [START included_in_inequality]
+    Article(title='Perl + Python = Parrot',
+            stars=5,
+            tags=['python', 'perl'])
+    # [END included_in_inequality]
+    # [START excluded_from_inequality]
+    Article(title='Introduction to Perl',
+            stars=3,
+            tags=['perl'])
+    # [END excluded_from_inequality]
+
+
+def query_article_in():
+    query = Article.query(Article.tags.IN(['python', 'ruby', 'php']))
+    return query
+
+
+def query_article_in_equivalent():
+    query = Article.query(ndb.OR(Article.tags == 'python',
+                                 Article.tags == 'ruby',
+                                 Article.tags == 'php'))
+    return query
+
+
+def query_article_nested():
+    query = Article.query(ndb.AND(Article.tags == 'python',
+                                  ndb.OR(Article.tags.IN(['ruby', 'jruby']),
+                                         ndb.AND(Article.tags == 'php',
+                                                 Article.tags != 'perl'))))
+    return query
+
+
+def query_greeting_order():
+    query = Greeting.query().order(Greeting.content, -Greeting.date)
+    return query
+
+
+def query_greeting_multiple_orders():
+    query = Greeting.query().order(Greeting.content).order(-Greeting.date)
+    return query
+
+
+def query_purchase_with_customer_key():
+    # [START purchase_with_customer_key_models]
+    class Customer(ndb.Model):
+        name = ndb.StringProperty()
+
+    class Purchase(ndb.Model):
+        customer = ndb.KeyProperty(kind=Customer)
+        price = ndb.IntegerProperty()
+    # [END purchase_with_customer_key_models]
+
+    def query_purchases_for_customer_via_key(customer_entity):
+        purchases = Purchase.query(
+            Purchase.customer == customer_entity.key).fetch()
+        return purchases
+
+    return Customer, Purchase, query_purchases_for_customer_via_key
+
+
+def query_purchase_with_ancestor_key():
+    # [START purchase_with_ancestor_key_models]
+    class Customer(ndb.Model):
+        name = ndb.StringProperty()
+
+    class Purchase(ndb.Model):
+        price = ndb.IntegerProperty()
+    # [END purchase_with_ancestor_key_models]
+
+    def create_purchase_for_customer_with_ancestor(customer_entity):
+        purchase = Purchase(parent=customer_entity.key)
+        return purchase
+
+    def query_for_purchases_of_customer_with_ancestor(customer_entity):
+        purchases = Purchase.query(ancestor=customer_entity.key).fetch()
+        return purchases
+
+    return (Customer, Purchase,
+            create_purchase_for_customer_with_ancestor,
+            query_for_purchases_of_customer_with_ancestor)
+
+
+def print_query():
+    print(Employee.query())
+    # -> Query(kind='Employee')
+    print(Employee.query(ancestor=ndb.Key(Manager, 1)))
+    # -> Query(kind='Employee', ancestor=Key('Manager', 1))
+
+
+def query_contact_with_city():
+    query = Contact.query(Contact.addresses.city == 'Amsterdam')
+    return query
+
+
+def query_contact_sub_entities_beware():
+    query = Contact.query(Contact.addresses.city == 'Amsterdam',  # Beware!
+                          Contact.addresses.street == 'Spear St')
+    return query
+
+
+def query_contact_multiple_values_in_single_sub_entity():
+    query = Contact.query(Contact.addresses == Address(city='San Francisco',
+                                                       street='Spear St'))
+    return query
+
+
+def query_properties_named_by_string_on_expando():
+    property_to_query = 'location'
+    query = FlexEmployee.query(ndb.GenericProperty(property_to_query) == 'SF')
+    return query
+
+
+def query_properties_named_by_string_for_defined_properties(keyword, value):
+    query = Article.query(Article._properties[keyword] == value)
+    return query
+
+
+def query_properties_named_by_string_using_getattr(keyword, value):
+    query = Article.query(getattr(Article, keyword) == value)
+    return query
+
+
+def order_query_results_by_property(keyword):
+    expando_query = FlexEmployee.query().order(ndb.GenericProperty('location'))
+
+    property_query = Article.query().order(Article._properties[keyword])
+
+    return expando_query, property_query
+
+
+def print_query_keys(query):
+    for key in query.iter(keys_only=True):
+        print(key)
+
+
+def reverse_queries():
+    # Set up.
+    q = Bar.query()
+    q_forward = q.order(Bar.key)
+    q_reverse = q.order(-Bar.key)
+
+    # Fetch a page going forward.
+    bars, cursor, more = q_forward.fetch_page(10)
+
+    # Fetch the same page going backward.
+    r_bars, r_cursor, r_more = q_reverse.fetch_page(10, start_cursor=cursor)
+
+    return (bars, cursor, more), (r_bars, r_cursor, r_more)
+
+
+def fetch_message_accounts_inefficient(message_query):
+    message_account_pairs = []
+    for message in message_query:
+        key = ndb.Key('Account', message.userid)
+        account = key.get()
+        message_account_pairs.append((message, account))
+
+    return message_account_pairs
+
+
+def fetch_message_accounts_efficient(message_query):
+    def callback(message):
+        key = ndb.Key('Account', message.userid)
+        account = key.get()
+        return message, account
+
+    message_account_pairs = message_query.map(callback)
+    # Now message_account_pairs is a list of (message, account) tuples.
+    return message_account_pairs
+
+
+def fetch_good_articles_using_gql_with_explicit_bind():
+    query = ndb.gql("SELECT * FROM Article WHERE stars > :1")
+    query2 = query.bind(3)
+
+    return query, query2
+
+
+def fetch_good_articles_using_gql_with_inlined_bind():
+    query = ndb.gql("SELECT * FROM Article WHERE stars > :1", 3)
+    return query