The Google App Engine Oil Framework

The Google App Engine Oil (GAEO) Framework

Lin-Chieh Shangkuan (ericsk)

Outline

Google App Engine overviewWhy we develop the GAEO frameworkWhat's done in GAEO 0.1GAEO's current & future featuresHow to start using GAEO (DEMO)GAEO linksQ & A

Current Google App Engine

An application server with pure Python runtime language

also a web server for you

(HTTP) Request-based environment

Uses BigTable as database

Application version control and seamless upgrades/degrades.

HTTPS support (*.appspot.com only)

Developing Applications onAppEngine

Request-based Configuration

ctrl_list = ['Tag', 'User', 'Ziza'] app = webapp.WSGIApplication([ ('/', IndexView), ('/home', HomeView), ('/explore', ExploreView), ('/replies', RepliesView), ('/signup', SignupView), ('/settings', SettingsView), ('/tags', TagsView), ('/m/([^\/\s]*)', MsgView), ('/f/([^\/\s]*)', FeedsView), ('/r/([^\/\s]*)', FeedsWithFriendsView), ('/u/([^\/\s]*)', UserView), ('/t/([^\/\s]*)', TagView), ] + [(r'/%s/(.*)' % s.lower(), eval(s + 'Controller')) for s in ctrl_list], debug=True)

Handle HTTP Request

class IndexView(webapp.RequestHandler): def get(self): # get the user object user = users.get_current_user() if user: # the user has logined self.redirect('/home')

template_values = { 'signin_url': users.create_login_url('/home'), }

Deployment

Why do we develop a framework on AppEngine?

GoalTo be familiar with AppEngineConvention over configuration

Structured, meaningful, parameterized URL

More helper methodsQuickly migrate from ZF or RailsFor team works

Software Architecture

.

.

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action

action

action

dispatcherclient

requestdispatch

response

Code Layout (0.2)$APP_BASE/ application/ controllers/ models/ templates/ assets/ css/ img/ js/ gaeo/ plugins/ app.yaml favicon.ico main.py

GAEO 0.1released at Sep. 19, 2008

GAEO URL Routing

Default:http://example.com/foo/bar/1234

controller: foo (FooController class)action: bar (bar method in FooController)id: 1234

Configurable & Parameterize:route.connect('/signin', controller='account', action='signin')route.connect('/user/:name', controller='user', action='show')route.connect('/foo/:action/:x/:y/:z', controller='foo')

Action Controller

Each request is distributed to an actionIn GAEO, an action is a method of an action controller

Create a controller class that extends gaeo.controller.BaseController

Implement the actionclass FooController(BaseController): def bar(self): """ TODO: do things for /foo/bar request """ pass

Response Helper

Use to_json method (uses simplejson) to convert a dict instance to a JSON string

Use render method to output different response data. (helps set the Content-Type header)

Use redirect method to redirect to another action (or URL)

Do something in before_action and after_action filters

Session support

Store data at server (mapping clients via Session-IDs that stores in cookies)

GAEO has designed a session interface and a memcache-session implementation.

Use self.session in the actions.

Model enhancement

Add some helper methodsupdate_attributessave, update

Naming query

A beginning of ORMbelongs_to method

Other helpers

Object shortcuts: requestresponsecookies

Mobile device detection_is_iphone_is_mobile

GAEO 0.2beta released at Oct. 31, 2008

Setuptools support

Now you can use easy_install gaeo to install the GAEO package.

Also available on pypi http://pypi.python.org/pypi/gaeo

Provided by gasolin

Scaffold

Quickly generates some common pagesnewlistshoweditcreateupdatedestroy

Provided by xeonchen

Plugins

Provides plugins system in GAEO

Install features on demand

3rd party development :-p

Other Enhancements

Global initializationapplication_init method (in ApplicationController)

AJAX/Form helpersgenerates some useful AJAX/form strings

The respond_to methodrespond content according to :format parameter

zip core importYou can zip the GAEO core to eliminate disk space cost

methods enhancements

GAEO's Future future

Roadmap

RESTfulmobile device support i18nnew template rendering engine...

GAEO Links

Document:http://doc.gaeo.org/

Project: http://code.google.com/p/google-app-engine-oil

Blog:http://blog.gaeo.org/

Groups:http://groups.google.com/group/google-app-engine-oil

Q & A

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