gaedatastore

import cgi
import datetime
import urllib
import wsgiref.handlers

from google.appengine.ext import db
from google.appengine.api import users
from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app

class Greeting(db.Model):
    """Models an individual Guestbook entry with an author, content and date."""
    print 'Greeting(db.Model)'
    author = db.UserProperty()
    content = db.StringProperty(multiline=True)
    date = db.DateTimeProperty(auto_now_add=True)

def guestbook_key(guestbook_name=None):
    """Constructs a Datastore key for a Guestbook entity with guestbook_name."""
    print 'guestbook_key function'
    return db.Key.from_path('Guestbook', guestbook_name or 'default_guestbook')

class MainPage(webapp.RequestHandler):
    def get(self):
        print 'MainPage  class'
        self.response.out.write('<html><body>')
        guestbook_name=self.request.get('guestbook_name')

        # Ancestor Queries, as shown here, are strongly consistent with the High
        # Replication Datastore. Queries that span entity groups are eventually
        # consistent. If we omitted the ancestor from this query there would be a
        # slight chance that Greeting that had just been written would not show up
        # in a query.
        greetings = db.GqlQuery("SELECT * "
                                "FROM Greeting  "
                                "WHERE ANCESTOR IS :1 "
                                "ORDER BY date DESC LIMIT 10",
                                guestbook_key(guestbook_name))

        for greeting in greetings:
            if greeting.author:
                self.response.out.write(
                    '<b>%s</b> wrote:' % greeting.author.nickname())
            else:
                self.response.write('An anonymous person wrote:')
            self.response.out.write('<blockquote>%s</blockquote>' % cgi.escape(greeting.content))

            self.response.out.write("""
                <form action="/sign?%s" method="post">
                    <div><textarea name="content" rows="3" cols="60"></textarea></div>
                    <div><input type="submit" value="Sign Guestbook"></div>
                </form>
                <hr>
                <form>Guestbook name: <input value="%s" name="guestbook_name">
                <input type="submit" value="switch"></form>
            </body>
        </html>""" % (urllib.urlencode({'guestbook_name': guestbook_name}),
                            cgi.escape(guestbook_name)))

class Guestbook(webapp.RequestHandler):
    def post(self):
        print 'Guestbook'
        # We set the same parent key on the 'Greeting' to ensure each greeting is in
        # the same entity group. Queries across the single entity group will be
        # consistent. However, the write rate to a single entity group should
        # be limited to ~1/second.
        guestbook_name = self.request.get('guestbook_name')
        greeting = Greeting(parent=guestbook_key(guestbook_name))

        if users.get_current_user():
            greeting.author = users.get_current_user()

        greeting.content = self.request.get('content')
        greeting.put()
        self.redirect('/?' + urllib.urlencode({'guestbook_name': guestbook_name}))

application = webapp.WSGIApplication([('/', MainPage), ('/sign', Guestbook)], debug=True)

def main():
    print 'main function()'
    run_wsgi_app(application)

if __name__ == '__main__':
    print 'Start'
    main()