Gae

Google App Engine入門課程

國網中心格網技術組
專案助理研究員鄭宗碩, Zong-shuo Jheng
zsjheng@nchc.org.tw
參考網頁: http://nchc-gae.blogspot.com

Outline
• What is Google App Engine
• Prerequirements for a new pilot
• Hello Google App Engine!
• Pieces of a flying GAE
• Data-storing black box - Google DataStore

NCHC, Google App Engine experience course. 2009

What is Google App Engine
• Hosting services on Google cloud platform
• Benefited by Google File System, BigTable
• Free for limited accessing
(10 free Web AP, up to 500MB of storage, up to 5 million page views a month, 2
billion CPU clock cycles one day)


Prerequirements for a new pilot
• Python runtime
http://python.org/

• Google App Engine SDK
http://code.google.com/appengine/
~/:> upzip google_appengine_1.2.2.zip
appcfg.py, dev_appserver.py

• Eclipse with PyDev
http://nchc-gae.blogspot.com/2009/05/eclipse-pydev-google-app-engine.html

• Applying for a free account
http://nchc-gae.blogspot.com/2009/05/google-app-engine.html


Outline
• What is Google App Engine
• Prerequirements for a new pilot
• Hello Google App Engine!
• Pieces of a flying GAE
• Storing data in Google DataStore


Hello Google App Engine!
<<app.yaml>> << hello.py >>
application: HelloGAE from google.appengine.ext import webapp
version: 1 from google.appengine.ext.webapp.util import run_wsgi_app
runtime: python
api_version: 1 class MainPage(webapp.RequestHandler):
def get(self):
handlers: self.response.headers['Content-Type'] = 'text/html; charset=UTF-8'
- url: /.* self.response.out.write(quot;Hello Google App Engine!quot;)
script: hello.py
application = webapp.WSGIApplication([('/', MainPage)],
debug=True)
def main():
run_wsgi_app(application)

if __name__ == quot;__main__quot;:
main()


Pieces of a flying GAE
• Configuration files
• MVC design pattern
• webapp framework
• Template
• Google User service API
• Dashboard


Configuration files
• app.yaml
• cron.yaml
• index.yaml


MVC design pattern
<<User-defined Handler class>> <<DataStore>>
Eg. class Main_handler(webapp.RequestHandler) from google.appengine.ext
import db

<<Template>>
from google.appengine.ext.webapp
import template


webapp framework
<< hello.py >>
from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app

class MainPage(webapp.RequestHandler):
def get(self): 3
self.response.headers['Content-Type'] = 'text/html; charset=UTF-8'
self.response.out.write(quot;Hello Google App Engine!quot;)

application = webapp.WSGIApplication([('/', MainPage)],
debug=True)
def main(): 2 3
run_wsgi_app(application) 1 2
1
if __name__ == quot;__main__quot;:
main()


Template
Reference : http://nchc-gae.blogspot.com/2009/05/google-app-engine-template-tutorial.html

<<template/index.htm>>
<html>
<head><title>Hello Template</title></head>
<body> {{ Welcome_msg }} </body>
</html>

<<index.py>>
import os
from google.appengine.ext.webapp import template

class Main_handler(webapp.RequestHandler):
def get(self):
template_value = { 'Welcome_msg': 'Hello, Template!' }
path = os.path.join(os.path.dirname(__file__),'template/index.htm')
outstr = template.render(path, template_value)
self.response.out.write(outstr)

Google User service API
from google.appengine.api import users
create_login_url(dest_url)
User class: create_logout_url(dest_url)
class MyHandler(webapp.RequestHandler):
email get_current_user()
def get(self):
nickname() is_current_user_admin()
user = users.get_current_user()
email() if user:
user_id() greeting = (quot;Welcome, %s! (<a href=quot;%squot;>sign out</a>)quot; %
(user.nickname(), users.create_logout_url(quot;/quot;)))
else:
greeting = (quot;<a href=quot;%squot;>Sign in or register</a>.quot; %
users.create_login_url(quot;/quot;))
self.response.out.write(quot;<html><body>%s</body></html>quot; % greeting)

user = users.get_current_user()
if user:
print quot;Welcome, %s!quot; % user.nickname()
if users.is_current_user_admin():
print quot;<a href=quot;/admin/quot;>Go to admin area</a>quot;

Data-storing black box - Google DataStore
• Types and Property Classes
http://code.google.com/intl/en/appengine/docs/python/datastore/typesandpropertyclasses.html

• Entity and Model
from google.appengine.ext import db

class Pet(db.Model):
name = db.StringProperty(required=True)
type = db.StringProperty(required=True, choices=set([quot;catquot;, quot;dogquot;, quot;birdquot;]))
birthdate = db.DateProperty()
weight_in_pounds = db.IntegerProperty()

pet = Pet(name=quot;Fluffyquot;,
type=quot;catquot;,
owner=users.get_current_user())
pet.weight_in_pounds = 24

• Creating and Deleting Data
pet.put() / db.put(pet), pet.delete() / db.delete(pet)

• Getting data
class Story(db.Model):
title = db.StringProperty()
date = db.DateTimeProperty()
query = Story.all()
query.filter('title =', 'Foo')
query.order('-date')
query.ancestor(key)

query.filter('title =', 'Foo').order('-date').ancestor(key)


query = db.GqlQuery(quot;SELECT * FROM Story WHERE title = :1 quot;
quot;AND ANCESTOR IS :2 quot;
quot;ORDER BY date DESCquot;,
'Foo', key)

query = Story.gql(quot;WHERE title = :title quot;
quot;AND ANCESTOR IS :parent quot;
quot;ORDER BY date DESCquot;,
title='Foo', parent=key)


Gae

Recomendados

Recomendados

Más contenido relacionado

La actualidad más candente

La actualidad más candente (20)

Similar a Gae

Similar a Gae (20)

Gae