# Copyright 2016 Google Inc.
#
# 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.api import users
from google.appengine.ext import ndb
import webapp2
class Guestbook(ndb.Model):
content = ndb.StringProperty()
post_date = ndb.DateTimeProperty(auto_now_add=True)
class Account(ndb.Model):
email = ndb.StringProperty()
nickname = ndb.StringProperty()
def nick(self):
return self.nickname or self.email # Whichever is non-empty
class Message(ndb.Model):
text = ndb.StringProperty()
when = ndb.DateTimeProperty(auto_now_add=True)
author = ndb.KeyProperty(kind=Account) # references Account
class MainPage(webapp2.RequestHandler):
def get(self):
if self.request.path == "/guestbook":
if self.request.get("async"):
self.get_guestbook_async()
else:
self.get_guestbook_sync()
elif self.request.path == "/messages":
if self.request.get("async"):
self.get_messages_async()
else:
self.get_messages_sync()
def get_guestbook_sync(self):
uid = users.get_current_user().user_id()
acct = Account.get_by_id(uid) # I/O action 1
qry = Guestbook.query().order(-Guestbook.post_date)
recent_entries = qry.fetch(10) # I/O action 2
# ...render HTML based on this data...
self.response.out.write(
"{}".format(
"".join("{}
".format(entry.content) for entry in recent_entries)
)
)
return acct, qry
def get_guestbook_async(self):
uid = users.get_current_user().user_id()
acct_future = Account.get_by_id_async(uid) # Start I/O action #1
qry = Guestbook.query().order(-Guestbook.post_date)
recent_entries_future = qry.fetch_async(10) # Start I/O action #2
acct = acct_future.get_result() # Complete #1
recent_entries = recent_entries_future.get_result() # Complete #2
# ...render HTML based on this data...
self.response.out.write(
"{}".format(
"".join("{}
".format(entry.content) for entry in recent_entries)
)
)
return acct, recent_entries
def get_messages_sync(self):
qry = Message.query().order(-Message.when)
for msg in qry.fetch(20):
acct = msg.author.get()
self.response.out.write("On {}, {} wrote:".format(msg.when, acct.nick()))
self.response.out.write("
{}".format(msg.text))
def get_messages_async(self):
@ndb.tasklet
def callback(msg):
acct = yield msg.author.get_async()
raise ndb.Return(
"On {}, {} wrote:\n{}".format(msg.when, acct.nick(), msg.text)
)
qry = Message.query().order(-Message.when)
outputs = qry.map(callback, limit=20)
for output in outputs:
self.response.out.write("
{}
".format(output))
app = webapp2.WSGIApplication(
[
("/.*", MainPage),
],
debug=True,
)