# 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.

# [START all]

from google.appengine.ext import ndb

import webapp2

COUNTER_KEY = 'default counter'

class Counter(ndb.Model):

count = ndb.IntegerProperty(indexed=False)

class UpdateCounterHandler(webapp2.RequestHandler):

def post(self):

amount = int(self.request.get('amount'))

# This task should run at most once per second because of the datastore

# transaction write throughput.

@ndb.transactional

def update_counter():

counter = Counter.get_or_insert(COUNTER_KEY, count=0)

counter.count += amount

counter.put()

update_counter()

app = webapp2.WSGIApplication([

('/update_counter', UpdateCounterHandler)

], debug=True)

# [END all]