# 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]