guestbook/guestbook7_memcache.py

   1 import cgi
   2 import os
   3 import pickle
   4
   5 from google.appengine.api import users
   6 from google.appengine.ext import webapp
   7 from google.appengine.ext.webapp.util import run_wsgi_app
   8 from google.appengine.ext import db
   9 from google.appengine.ext.webapp import template
  10 from google.appengine.api import memcache
  11
  12 MEMCACHE_GREETINGS = 'greetings'
  13
  14 class Greeting(db.Model):
  15   author = db.UserProperty()
  16   content = db.StringProperty(multiline=True)
  17   date = db.DateTimeProperty(auto_now_add=True)
  18
  19 class MainPage(webapp.RequestHandler):
  20   def get(self):
  21     greetingsString = memcache.get(MEMCACHE_GREETINGS)
  22     if greetingsString is not None:
  23       greetings = pickle.loads(greetingsString)
  24     else:
  25       greetings_query = Greeting.all().order('-date')
  26       greetings = greetings_query.fetch(10)
  27       if not memcache.set(MEMCACHE_GREETINGS, pickle.dumps(greetings)):
  28         logging.error("Memcache set failed.")
  29
  30     if users.get_current_user():
  31       url = users.create_logout_url(self.request.uri)
  32       url_linktext = 'Logout'
  33     else:
  34       url = users.create_login_url(self.request.uri)
  35       url_linktext = 'Login'
  36
  37     template_values = {
  38       'greetings': greetings,
  39       'url': url,
  40       'url_linktext': url_linktext,
  41       }
  42
  43     path = os.path.join(os.path.dirname(__file__), 'index.html')
  44     self.response.out.write(template.render(path, template_values))
  45
  46
  47 class Guestbook(webapp.RequestHandler):
  48   def post(self):
  49     greeting = Greeting()
  50
  51     if users.get_current_user():
  52       greeting.author = users.get_current_user()
  53
  54     greeting.content = self.request.get('content')
  55     greeting.put()
  56     memcache.delete(MEMCACHE_GREETINGS)
  57     self.redirect('/')
  58
  59 application = webapp.WSGIApplication(
  60                                      [('/', MainPage),
  61                                       ('/sign', Guestbook)],
  62                                      debug=True)
  63
  64 def main():
  65   run_wsgi_app(application)
  66
  67 if __name__ == "__main__":
  68   main()