6. Defining views

6.1. Overview

views.py is a module in which you need to write your business logic. A single view must be callable, must have request object as a first argument, and must return an instance of werkzeug.Response.

6.1.1. The simplest view

Let’s look at the simplest view.

myapp/views.py:

# -*- coding: utf-8 -*-
# The simplest view.

from werkzeug import Response
def index(request):
  return Response("Hello")

It’s super easy. What if you want to use html templates for rendering pages. Please use kay.utils.render_to_response() for this purpose:

myapp/views.py:

# -*- coding: utf-8 -*-
# The simplest view.

from werkzeug import Response
from kay.utils import render_to_response

def index(request):
  return render_to_response('myapp/index.html', {'message': 'Hello'})

That’s it. Please see kay.utils.render_to_response() for more details.

6.1.2. Class based views

You can use callable object as a view. For this purpose, you can extend kay.handlers.BaseHandler and define your own handler class.

Here is a example for a simple class based view:

from kay.handlers import BaseHandler

from myapp.models import Comment

# ..

class CommentHandler(BaseHandler):
  def prepare(self):
    self.comments = Comment.all().order('-created').fetch(100)
    self.form = CommentForm()

  def get(self):
    return render_to_response('myapp/index.html',
                              { 'comments': self.comments,
                               'form': self.form.as_widget()})

  def post(self):
    if self.form.validate(self.request.form):
      if self.request.user.is_authenticated():
        user = self.request.user
      else:
        user = None
      new_comment = Comment(body=self.form['comment'],user=user)
      new_comment.put()
      return redirect(url_for('myapp/index'))
    return self.get()

comment_handler = CommentHandler()

These handler must have one or more methods with a name as the same as lower-cased HTTP Methods to corresponds with. It can have prepare method to do some task before above methods whatever HTTP method the current HTTP request uses.