deeply love python: 8月 2008

2008年8月29日星期五

using django with app engine

1. create django project

django-admin.py startproject Test

2. add main.py in project:

# Google App Engine imports.

from google.appengine.ext.webapp import util

from django.core.management import setup_environ

import settings

setup_environ(settings)

# Force Django to reload its settings.

from django.conf import settings

settings._target = None

import django.core.handlers.wsgi

import django.core.signals

import django.db

import django.dispatch.dispatcher

# Unregister the rollback event handler.

django.dispatch.dispatcher.disconnect(

django.db._rollback_on_exception,

django.core.signals.got_request_exception)

def main():

# Create a Django application for WSGI.

application = django.core.handlers.wsgi.WSGIHandler()

# Run the WSGI CGI handler with that application.

util.run_wsgi_app(application)

if __name__ == '__main__':

main()

3. add app.yaml in project

application: test

version: 1

runtime: python

api_version: 1

handlers:

- url: /.*

script: main.py

4. dev_appserver.py Test

2008年8月28日星期四

webpage about django & app engine

http://www.42topics.com/dumps/django/docs.html

http://www.42topics.com/dumps/appengine/doc.html

create application on app engine

1. create an application from http://appengine.google.com/

application identifier must be the same as application in app.yaml

2. upload application

appcfg.py update helloworld

3. by default,

the application url is http://helloworld.appspot.com/

using static files

using css:

add following lines in yaml

- url: /stylesheets

static_dir: stylesheets

add a directory stylesheets under project directory

css files are in this directory

add following lines in html

<head>

</head>

2008年8月26日星期二

free svn server

assembla

http://www.assembla.com

template in webapp

helloworld.py

import cgi

from google.appengine.ext import db

import os

from google.appengine.ext.webapp import template

from google.appengine.ext import webapp

from google.appengine.ext.webapp.util import run_wsgi_app

from google.appengine.api import users

class Greeting(db.Model):

author = db.UserProperty()

content = db.StringProperty(multiline=True)

date = db.DateTimeProperty(auto_now_add=True)

class MainPage(webapp.RequestHandler):

def get(self):

greetings_query = Greeting.all().order('-date')

greetings = greetings_query.fetch(10)

if users.get_current_user():

url = users.create_logout_url(self.request.uri)

url_linktext = 'Logout'

else:

url = users.create_login_url(self.request.uri)

url_linktext = 'Login'

template_values = {

'greetings': greetings,

'url': url,

'url_linktext': url_linktext,

}

path = os.path.join(os.path.dirname(__file__), 'index.html')

self.response.out.write(template.render(path, template_values))

class Guestbook(webapp.RequestHandler):

def post(self):

greeting = Greeting()

if users.get_current_user():

greeting.author = users.get_current_user()

greeting.content = self.request.get('content')

greeting.put()

self.redirect('/')

application = webapp.WSGIApplication( [('/', MainPage), ('/sign', Guestbook)], debug=True)

def main():

run_wsgi_app(application)

if __name__ == "__main__":

main()

index.html:

<html>

<body>

{% for greeting in greetings %}

{% if greeting.author %}

<b>{{ greeting.author.nickname }}</b> wrote:

{% else %}

An anonymous person wrote:

{% endif %}

<blockquote>{{ greeting.content|escape }}</blockquote>

{% endfor %}

</form>

<a href="{{ url }}">{{ url_linktext }}</a>

</body>

</html>

datastore api

define a model & create an entity

example :

# import db & users

from google.appengine.ext import db

from google.appengine.api import users

# define a model, inherit from db.Model

class Pet(db.Model):

name = db.StringProperty(required=True)

type = db.StringProperty(required=True, choices=set(["cat", "dog", "bird"]))

birthdate = db.DateProperty()

weight_in_pounds = db.IntegerProperty()

spayed_or_neutered = db.BooleanProperty()

owner = db.UserProperty()

# create an entity

pet = Pet(name="Fluffy",

type="cat",

owner=users.get_current_user())

pet.weight_in_pounds = 24

# store the entity

pet.put()

_____________________________________________________________

get entity from datastore

1. using db.GqlQuery

ex:

user_pets = db.GqlQuery("SELECT * FROM Pet WHERE pet.owner = :1",

users.get_current_user())

db's property:

1. db.StringProperty

2.db.DateProperty

import cgi

from google.appengine.ext import db

from google.appengine.ext import webapp

from google.appengine.ext.webapp.util import run_wsgi_app

from google.appengine.api import users

class Greeting(db.Model):

author = db.UserProperty()

content = db.StringProperty(multiline=True)

date = db.DateTimeProperty(auto_now_add=True)

class MainPage(webapp.RequestHandler):

def get(self):

self.response.out.write('<html><body>')

greetings = db.GqlQuery("SELECT * FROM Greeting ORDER BY date DESC LIMIT 10")

for greeting in greetings:

if greeting.author:

self.response.out.write('<b>%s</b> wrote:' % greeting.author.nickname())

else:

self.response.out.write('An anonymous person wrote:')

self.response.out.write('<blockquote>%s</blockquote>' %

cgi.escape(greeting.content))

# Write the submission form and the footer of the page

self.response.out.write("""

</form> </body></html>

""")

class Guestbook(webapp.RequestHandler):

def post(self):

greeting = Greeting()

if users.get_current_user():

greeting.author = users.get_current_user()

greeting.content = self.request.get('content')

greeting.put()

self.redirect('/')

application = webapp.WSGIApplication( [('/', MainPage), ('/sign', Guestbook)], debug=True)

def main():

run_wsgi_app(application)

if __name__ == "__main__":

main()

get data from datastore:

method 1:

db.GqlQuery("SELECT * FROM Greeting ORDER BY date DESC LIMIT 10")

method 2:

Greeting.gql("ORDER BY date DESC LIMIT 10")

method 3:

Greeting.gql("WHERE author = :1 ORDER BY date DESC",

users.get_current_user())

method 4:

Greeting.gql("WHERE author = :author ORDER BY date DESC",

author=users.get_current_user())

method 5:

greetings = Greeting.all()

greetings.filter("author =", users.get_current_user())

greetings.order("-date")

Clearing the Development Server Datastore

ex:

dev_appserver.py --clear_datastore helloworld/

form in webapp

import cgi

from google.appengine.ext import webapp

from google.appengine.ext.webapp.util import run_wsgi_app

from google.appengine.api import users

class MainPage(webapp.RequestHandler):

def get(self):

self.response.out.write("""

<html>

<body>

</form>

</body>

</html>""")

class Guestbook(webapp.RequestHandler):

def post(self):

self.response.out.write('<html><body>You wrote:<pre>')

self.response.out.write(cgi.escape(self.request.get('content')))

self.response.out.write('</pre></body></html>')

application = webapp.WSGIApplication( [('/', MainPage), ('/sign', Guestbook)], debug=True)

def main():

run_wsgi_app(application)

if __name__ == "__main__":

main()

users service

from google.appengine.ext import webapp

from google.appengine.ext.webapp.util import run_wsgi_app

from google.appengine.api import users

class MainPage(webapp.RequestHandler):

def get(self):

user = users.get_current_user()

if user:

self.response.headers['Content-Type'] = 'text/plain'

self.response.out.write('Hello, ' + user.nickname())

else:

self.redirect(users.create_login_url(self.request.uri))

application = webapp.WSGIApplication( [('/', MainPage)], debug=True)

def main():

run_wsgi_app(application)

if __name__ == "__main__":

main()

self.request.uri is current uri. Hence, after successful login, user can back here

webapp framework

from google.appengine.ext import webapp

from google.appengine.ext.webapp.util import run_wsgi_app

class MainPage(webapp.RequestHandler):

def get(self):

self.response.headers['Content-Type'] = 'text/plain'

self.response.out.write('Hello, webapp World!')

application = webapp.WSGIApplication( [('/', MainPage)], debug=True)

def main():

run_wsgi_app(application)

if __name__ == "__main__":

main()

a hello world page

1. create project directory:
helloworld

2. in the directory, create two files

(1)helloworld.py:

print 'Content-Type: text/plain'

print ''

print 'Hello, world!'

(2)app.yaml

application: helloworld

version: 1

runtime: python

api_version: 1

handlers:

- url: /.*

script: helloworld.py

url: /.*

script: helloworld.py means any url will be handled by helloworld.py

(3)run web server:

dev_appserver.py helloworld

(4) connect to server
127.0.0.1:8080

(5) update to google web server:
appcfg.py helloworld

2008年8月13日星期三

development python on eclipse

pydev:

add " http://pydev.sourceforge.net/updates/ " on eclipse's software update

deeply love python

2008年8月29日星期五

using django with app engine

2008年8月28日星期四

webpage about django & app engine

create application on app engine

using static files

2008年8月26日星期二

free svn server

template in webapp

datastore api

form in webapp

users service

webapp framework

a hello world page

2008年8月13日星期三

development python on eclipse

標籤

my other website

網誌存檔

關於我自己

2008年8月29日 星期五

2008年8月28日 星期四

2008年8月26日 星期二

2008年8月13日 星期三

標籤

my other website

網誌存檔

關於我自己

2008年8月29日星期五

2008年8月28日星期四

2008年8月26日星期二

2008年8月13日星期三