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# Copyright 2015 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.
"""
Sample App Engine application demonstrating how to use the Namespace Manager
API with Datastore.
For more information, see README.md.
"""
# [START all]
from google.appengine.api import namespace_manager
from google.appengine.ext import ndb
import webapp2
class Counter(ndb.Model):
count = ndb.IntegerProperty()
@ndb.transactional
def update_counter(name):
"""Increment the named counter by 1."""
counter = Counter.get_by_id(name)
if counter is None:
counter = Counter(id=name, count=0)
counter.count += 1
counter.put()
return counter.count
class DatastoreCounterHandler(webapp2.RequestHandler):
"""Increments counters in the global namespace as well as in whichever
namespace is specified by the request, which is arbitrarily named 'default'
if not specified."""
def get(self, namespace='default'):
global_count = update_counter('counter')
# Save the current namespace.
previous_namespace = namespace_manager.get_namespace()
try:
namespace_manager.set_namespace(namespace)
namespace_count = update_counter('counter')
finally:
# Restore the saved namespace.
namespace_manager.set_namespace(previous_namespace)
self.response.write('Global: {}, Namespace {}: {}'.format(
global_count, namespace, namespace_count))
app = webapp2.WSGIApplication([
(r'/datastore', DatastoreCounterHandler),
(r'/datastore/(.*)', DatastoreCounterHandler)
], debug=True)
# [END all]