This document provides an introduction and overview of developing Python applications on Google App Engine. It discusses how App Engine allows developers to focus on coding by handling infrastructure concerns like scaling. The document then demonstrates building a simple "guestbook" application on App Engine step-by-step, starting with a basic "Hello World" application and progressively adding features like additional pages, data storage using the datastore, and retrieving stored values.

1. Sebastián Serrano [email_address] twitter: sserrano44 http://www.lp-gtug.org Google App Engine + Python en 5 minutos

2. Cloud Computing??

3. 0% Administracion = 100% Desarrollo

5. Servicios del App Engine

6. Lenguajes

8. App Engine Dashboard

9. SDK Console

11. Arrancar un proyecto $ dev_appserver.py helloworld # run dev svr $ appcfg.py update helloworld # deploy live Linux, MacOS, etc. command-line: Windows GUI (y Mac):

12. Contenido basico app.yaml – archivo configuración main principal index.yaml – generado automáticamente para indexar nuestros datos main.py – el código de la aplicación

13. main.py

14. Local development server $ dev_appserver.py helloworld INFO 2009-03-04 17:51:22,354 __init__.py]

16. Modifying app.yaml application: helloworld version: 1 runtime: python api_version: 1 handlers: - url: .* script: main.py

17. Running the deploy script $ appcfg.py update helloworld Scanning files on local disk. Initiating update. Email: ...

18. You're live!

19. Demo time??

20. main.py: Skeleton application from google.appengine.ext import webapp from google.appengine.ext.webapp import util class MainHandler(webapp.RequestHandler): def get(self): self.response.out.write('Hello world!') def main(): application = webapp.WSGIApplication([('/', MainHandler)], debug=True) util.run_wsgi_app(application) if __name__ == '__main__': main()

21. main.py: Adding a handler from google.appengine.ext import webapp from google.appengine.ext.webapp.util import run_wsgi_app class MainHandler(webapp.RequestHandler): def get(self): self.response.out.write('<h1>Hello world!</h1>') self.response.out.write(''' <form action=&quot;/sign&quot; method=post> <input type=text name=content> <br><input type=submit value=&quot;Sign Guestbook&quot;> </form> ''') class GuestBook(webapp.RequestHandler): def post(self): self.response.out.write( '<h2>You wrote:</h2> %s' % self.request.get('content') ) application = webapp.WSGIApplication([ ('/', MainHandler), ('/sign', GuestBook), ], debug=True) # start_wsgi_app etc ...

22. main.py: Persisting to the datastore class GuestBook(webapp.RequestHandler): def post(self): greeting = Greeting() greeting.content = self.request.get('content') greeting.put() self.redirect('/')

23. main.py: Collecting values from the datastore class MainHandler(webapp.RequestHandler): def get(self): self.response.out.write('Hello world!') self.response.out.write('<h1>My GuestBook</h1><ol>') greetings = Greeting.all() for greeting in greetings: self.response.out.write('<li> %s' % greeting.content) self.response.out.write(''' </ol><hr> <form action=&quot;/sign&quot; method=post> <textarea name=content rows=3 cols=60></textarea> <br><input type=submit value=&quot;Sign Guestbook&quot;> </form> ''')

24. Live demo??