Appengine katse: autent ja andmebaas

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."""
  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."""
  return db.Key.from_path('Guestbook', guestbook_name or 'default_guestbook')


class MainPage(webapp.RequestHandler):
  def get(self):
    user = users.get_current_user()
    if user:      
      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.out.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)))
    else:
      self.redirect(users.create_login_url(self.request.uri)) 
    
    


class Guestbook(webapp.RequestHandler):
  def post(self):
    # 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():
  run_wsgi_app(application)


if __name__ == '__main__':
  main()