import cgi
from django.core.paginator import InvalidPage
from django.core.paginator import ObjectPaginator
from google.appengine.api import users
from google.appengine.ext import db
from google.appengine.ext import webapp
from google.appengine.ext.webapp import template
from google.appengine.ext.db import djangoforms

and next to create the Database Model….

class Test(db.Model):

   name = db.UserProperty()

   message = db.StringProperty(required=True)

   quantity = db.IntegerProperty(default=1)

   date = db.DateTimeProperty(auto_now_add=True)

   price = db.FloatProperty()

   email = db.EmailProperty()

Now, open main.py where you are saving your data. we need to create the form object based on the model….

class TestForm(djangoforms.ModelForm):
  class Meta:
    model = Test

def post(self):
    data = TestForm(data=self.request.POST) 

  if data.is_valid():
      save()
      self.redirect(‘/’)

            else:
                url = users.create_login_url(‘/’)
                self.response.out.write(‘You suck! enter some valid data’)

So what we are doing before inserting our input data in the datastore? As an example, we said quantity is an integer so it’s input value must be a number, message field cannot be empty as we set “required=true”. Like these we have set email property, date etc that will be checked by is_valid as it defined. But what about chars length and user logged in check?

def post(self):
        user = users.get_current_user()
        msg = self.request.get(‘msg’)
        if len(msg)<140 and user:
            do_something()
            self.redirect(‘/’)
        else:
            url = users.create_login_url(‘/’)
            self.response.out.write(‘Input length checked and loggied in user not found!’)