2008年8月26日 星期二
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 action="/sign" method="post">
<div><textarea name="content" rows="3" cols="60"></textarea></div>
<div><input type="submit" value="Sign Guestbook"></div>
</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 action="/sign" method="post">
<div><textarea name="content" rows="3" cols="60"></textarea></div>
<div><input type="submit" value="Sign Guestbook"></div>
</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 action="/sign" method="post">
<div><textarea name="content" rows="3" cols="60"></textarea></div>
<input type="submit" value="Sign Guestbook"></div>
</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:
helloworld
2. in the directory, create two files
(1)helloworld.py:
print 'Content-Type: text/plain'
(4) connect to server
127.0.0.1:8080
(5) update to google web server:
appcfg.py helloworld
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
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