Google Cookbook - Google App Engine

application = webapp.WSGIApplication([('/feeds/traveller', TravellerFeed)], debug = True)
def main():
    run_wsgi_app(application)
if __name__ == '__main__':
    main()

webapp.run(__name__, '/feeds/traveller', TravellerFeed)

class TravellerFeed(webapp.RequestHandler):
    def get(self):
        keys = self.request.get_all('key')
        days = int(self.request.get('days', '28'))
        group = Group.get(keys[0])
        user = User.fromId(group.userId)
        groups = [group.get(key).name for key in keys]

        feed = writer.xml('feed', xmlns = "http://www.w3.org/2005/Atom")

        userKey = user.key()
        link = 'http://trogger.net/traveller/%s' % userKey
        feed.link(link).id(userKey)
        if user.fullName:
            feed.title("Travel Notes for %s" % user.fullName).author.name(user.fullName)
        else:
            feed.title("Trave Notes")

        for record in Record.recent(user.id, 'notes', groups, days = days):
            if first:
                '''
                Use common data from the first record to fill out the general
                feed data - including the last updated date.
                '''
                first = False
                feed.updated(str(record.updated))
                trip = Trip.get(user.id, record.trip)
                link = 'http://trogger.net/trip/%s' % trip.key()
            entry = feed.entry
            entry.id(record.key()).title(record.title).updated(str(record.updated))
            entry.content(record.notes)
            if user.fullName:
                entry.author.name(user.fullName)
            entry.link(link)

        self.response.out.write(str(feed))

http://localhost:8080/feeds/traveller?key=agp0cm9nZ2VybmV0chULEgVHcm91cCIKVTE7UHJpdmF0ZQw

  appid
  java

application: appid 
version: python
runtime: python
api_version: 1
handlers:
- url: /
  script: main.py

import com.google.appengine.api.datastore.Key;
import javax.jdo.annotations.*;
@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Thing {
    @PrimaryKey
    @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
    private Key key;
    @Persistent
    private String name;
    @Persistent
    private int number;
    public Thing(String name, int number) {
        this.name = name;
        this.number = number;
    }
    public Key getKey() {
        return key;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getNumber() {
        return number;
    }
    public void setNumber(int number) {
        this.number = number;
    }
}

class Thing(db.Model):
  name = db.StringProperty()
  number = db.IntegerProperty()

from google.appengine.ext import db
from google.appengine.tools import bulkloader
class Thing(db.Model):
  name = db.StringProperty()
  number = db.IntegerProperty()
class ThingExporter(bulkloader.Exporter):
    def __init__(self):
        bulkloader.Exporter.__init__(self, 'Thing',
                                     [('name', str, None),
                                      ('number', str, None)
                                     ])
exporters = [ThingExporter]

application: appid 
version: python
runtime: python
api_version: 1
handlers:
- url: /remote_api
  script: $PYTHON_LIB/google/appengine/ext/remote_api/handler.py
  login: admin

appcfg.py update exporter

appcfg.py --server=python.latest.appid.appspot.com download_data exporter  --filename=data.csv --kind=Thing --config_file=exporter/thing_exporter.py 

#urls.py
from django.conf import settings
try:
    settings.configure()
except:
    pass
settings.LANGUAGE_CODE = 'zh-tw'
settings.USE_I18N = True
appdir = os.path.abspath( os.path.dirname( __file__ ) )
settings.LOCALE_PATHS = ( 
    os.path.join( appdir, 'locale' ),
 )
from django.utils.translation import *

# for each request
class Page(webapp.RequestHandler):
    def getLanguage(self):
        try:
            language = self.request.cookies['django_language']
            self.locate = language
            logging.info( "Get Language as %s" % self.locate )
        except:
            from django.conf import settings
            self.locate = settings.LANGUAGE_CODE
            logging.info( "Set Language as %s" % self.locate )            
        translation.activate( self.locate )
    def get(self):
        self.getLanguage()
        #...

class TripKML(webapp.RequestHandler):
    def get(self):
        try:
            ...
        except DeadlineExceededError:
            self.response.clear()
            self.response.set_status(500)
            self.message("This operation could not be completed in time...")
application = webapp.WSGIApplication([('/service/tripKML', TripKML)], debug = True)
def main():
    run_wsgi_app(application)
if __name__ == '__main__':
    main()

            self.traveller = User.fromId(int(self.request.get('traveller')))
            trip = self.request.get('trip')

        self.response.headers['Content-Type'] = 'application/vnd.google-earth.kml+xml'

### in queue.yaml
queue:
- name: hothandler
  rate: 20/m
  bucket_size: 1

### in cron.yaml
cron:
- description: ensure hot handler
  url: /_ah/queue/hothandler/start
  schedule: every 4 hours

### in app.yaml
handlers:
- url: /_ah/queue/hothandler/.*
  script: hothandler.py
  login: admin

### in hothandler.py
"""
Copyright (C)  2009  twitter.com/rcb

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
"""
import random
from wsgiref.handlers import CGIHandler
from google.appengine.api.labs import taskqueue
from google.appengine.api import memcache
from google.appengine.api.capabilities import CapabilitySet
memcache_service = CapabilitySet('memcache', methods=['set','get'])
hot_handler_queue = taskqueue.Queue(name='hothandler')
HOT_HANDLER_PREFIX = '/_ah/queue/hothandler/'
def wsgi_app(env, res):
    """ visit '/_ah/queue/hothandler/start' as admin to start a task """
    token = env['PATH_INFO'].replace(HOT_HANDLER_PREFIX,'')
    cur_token = memcache.get(HOT_HANDLER_PREFIX)
    if cur_token is None:
        if not memcache_service.is_enabled():
            cur_token = token
    if token in [cur_token, 'start']:
        next_token = str(random.random())
        url = '%s%s'%(HOT_HANDLER_PREFIX, next_token)
        next_task = taskqueue.Task(countdown=10, url=url)
        hot_handler_queue.add(next_task)
        memcache.set(HOT_HANDLER_PREFIX, next_token)
    res('200 OK',[('Content-Type','text/plain')])
    return ['ok']
def main():
    CGIHandler().run(wsgi_app)
    
if __name__ == '__main__':
    main()

    byte[] bmp_data = doRender("Render this text into a bitmap");
    // bmp_data contains a BMP file

def run_tasks(request):
    """
    KLUDGE!!
    Provides automatic task execution on dev sdk. 
    1. Setup this view func under the url /run_tasks.
    2. If you aren't using django, modify end. (HttpResponse and redirect)
    3. Run the following in a shell (you may need to change to the port number):
        while true; do \
        wget -qO - http://localhost:8085/run_tasks/ | wget --keep-session-cookies -i - --delete-after --wait=5; \
        sleep 60; \
        done
    Todo:
        - Add support for tasks that POST
        - Add support for rate (requests per second)
    """
    import os
    if os.environ['SERVER_SOFTWARE'].startswith('Development'):
        from datetime import datetime
        from google.appengine.api import apiproxy_stub_map
        stub = apiproxy_stub_map.apiproxy.GetStub('taskqueue')
        tasks = []
        #get all the tasks for all the queues
        for queue in stub.GetQueues():
            tasks.extend( stub.GetTasks(queue['name']) )
        #keep only tasks that need to be executed
        now = datetime.now()
        tasks = filter(lambda t: datetime.strptime(t['eta'],'%Y/%m/%d %H:%M:%S')