Google App Engine in 40 minutes (the absolute essentials)

Google App Engine in 40 Minutes

(The Absolute Essentials)

Paul Barry – Institute of Technology, Carlow in Ireland

PyCon Ireland 2011

2

Grab the slides:

http://paulbarry.itcarlow.ie/GAE.pdf

The Absolute Essentials in 40 Minutes...

6

What is Google App Engine?

7

Cloud-based Application Deployment Environment

8

Integrated Collection of Google APIs

9

Guido's Playground

10

Is App Engine “just another framework”?

11

It is all about your data...

12

Think of App Engine as a highly scalable,
distributed database server that you can program
with Python 2.5...

13

Think of App Engine as a highly scalable,
distributed database server that you can program
with Python 2.5...

and (cough) Java and (cough, cough) Go

14

Let's solve a real problem...

16

Step 1

Download the SDK from:

http://code.google.com/appengine/

and sign-up for an App Engine account ID

21

Step 2

Create a new project...

22

...by creating an app.yaml file

application: dwwgapp
version: 1
runtime: python
api_version: 1

handlers:
- url: /static
static_dir: static

- url: /.*
script: dwwgapp.py
23

Step 3

Model Your Data

24

Create dwwgDB.py (1 of 3)
from google.appengine.ext import db

25


class Sighting(db.Model):

26


class Sighting(db.Model):
name = db.StringProperty()
email = db.StringProperty()
date = db.DateProperty()
time = db.TimeProperty()
location = db.StringProperty()
fin_type = db.StringProperty()
whale_type = db.StringProperty()
blow_type = db.StringProperty()
wave_type = db.StringProperty()
28

Step 4

Define your UI in HTML

29

The header.html template

<html>
<head>
<title>{{ title }}</title>
</head>
<body>
<h1>{{ title }}</h1>

30

The footer.html template

<p> {{ links }} </p>
</body>
</html>

31

The form_start.html template

<form method=”POST” action=”/”>
<table>

32

The form_end.html

<tr><th> </th>
<td><input type="submit"
value="{{ sub_title }}"></td>
</tr>
</table>
</form>

33

Render some HTML

from google.appengine.ext.webapp import template

html = template.render('templates/header.html',
{'title': 'Report a Possible Sighting'})

34

Rendering a Page


html = html + template.render('templates/form_start.html', {})

# Do something in here to render the form?!?!?!?!?!?!?

html = html + template.render('templates/form_end.html',
{'sub_title': 'Submit Sighting'})
html = html + template.render('templates/footer.html', {'links': ''})

35

Step 5

Write code to render your form

36

Django Forms to the Rescue!

from google.appengine.ext.db import djangoforms

import dwwgDB

class SightingForm(djangoforms.ModelForm):
class Meta:
model = dwwgDB.Sighting

37

Rendering a Page, Again



html = html + str(SightingForm())


38

Step 6

Tie it all together with logic

39

You need to start your webapp

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

…

app = webapp.WSGIApplication([('/.*', SightingInputPage)], debug=True)

def main():
run_wsgi_app(app)

if __name__ == '__main__':
main()

40

Remember the app.yaml file?

version: 1
runtime: python
api_version: 1

handlers:
- url: /static
static_dir: static

- url: /.*
script: dwwgapp.py
41

Put this code in dwwgapp.py

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

…

app = webapp.WSGIApplication([('/.*', SightingInputPage)], debug=True)

def main():
run_wsgi_app(app)

if __name__ == '__main__':
main()

42

What's this SightingInputPage thing?

43

Responding to a GET Request

class SightingInputPage(webapp.RequestHandler):
def get(self):
self.response.out.write(html)

44

Step 7

Take your local app for a spin

45

Click the “Run” button...

or

$ dev_appserver.py dwwgapp 46

Looks kinda shitty, doesn't it?

48

Add a little CSS goodness..

<link type="text/css" rel="stylesheet" href="/static/dwwg.css" />
<link type="text/css" rel="stylesheet" href="/static/styledform.css" />

49

...and some code to dwwgDB.py

_FINS = ['Falcate', 'Triangular', 'Rounded']
_WHALES = ['Humpback', 'Orca', 'Blue', 'Killer', 'Beluga', 'Fin', 'Gray', 'Sperm']
_BLOWS = ['Tall', 'Bushy', 'Dense']
_WAVES = ['Flat', 'Small', 'Moderate', 'Large', 'Breaking', 'High']

...

location = db.StringProperty(multiline=True)
fin_type = db.StringProperty(choices=_FINS)
whale_type = db.StringProperty(choices=_WHALES)
blow_type = db.StringProperty(choices=_BLOWS)
wave_type = db.StringProperty(choices=_WAVES)

50

Step 8

Do something with your data

52

You need to POST data!

POST data with put()

53

def get(self):

54

def get(self):

def post(self):

55

def get(self):

def post(self):
new_sighting = dwwgDB.Sighting()

56

def get(self):

def post(self):
new_sighting.name = self.request.get('name')
new_sighting.email = self.request.get('email')
new_sighting.date = self.request.get('date')
new_sighting.time = self.request.get('time')
new_sighting.location = self.request.get('location')
new_sighting.fin_type = self.request.get('fin_type')
new_sighting.whale_type = self.request.get('whale_type')
new_sighting.blow_type =self.request.get('blow_type')
new_sighting.wave_type = self.request.get('wave_type')

57

def get(self):

def post(self):
new_sighting.name = self.request.get('name')
new_sighting.email = self.request.get('email')
new_sighting.date = self.request.get('date')
new_sighting.time = self.request.get('time')
new_sighting.location = self.request.get('location')
new_sighting.fin_type = self.request.get('fin_type')
new_sighting.whale_type = self.request.get('whale_type')
new_sighting.blow_type =self.request.get('blow_type')
new_sighting.wave_type = self.request.get('wave_type')

new_sighting.put()

58

And don't forget to say “Thanks!”

html = template.render('templates/header.html', {'title': 'Thank you!'})
html = html + "<p>Thank you for providing your sighting data.</p>"
html = html + template.render('templates/footer.html',
{'links': 'Enter <a href="/">another sighting</a>.'})


59

Step 9

Deploy to Google's cloud

61

Click the “Deploy” button...

or

$ appcfg.py upload dwwgapp/ 62

http://dwwgapp.appspot.com

63

Step 10

Realise your not done...

64

Damn That Spam!

Some smart-alec posted a sighting
of a Great White Shark on the top
of Mount Leinster...

65

A tiny config tweak to app.yaml...
version: 1
runtime: python
api_version: 1

handlers:
- url: /static
static_dir: static

- url: /.*
script: dwwgapp.py
login: required
67

...and two tiny code changes

Add this to the dwwgDB.py model:
which_user = db.UserProperty()

Add this to your post() method in dwwgapp.py:

new_sighting.which_user = users.get_current_user()

68

http://dwwgapp.appspot.com

69

http://appengine.google.com

70

And after all that,
what do you end up with?

71

Want to learn more
about this talk's example code?

73

Head First Python

74

Don't forget to check out
the App Engine Tutorial on Sunday
with Seán Murphy

75

Google App Engine in 40 minutes (the absolute essentials)

Recomendados

Recomendados

Más contenido relacionado

La actualidad más candente

La actualidad más candente (16)

Destacado

Destacado (6)

Similar a Google App Engine in 40 minutes (the absolute essentials)

Similar a Google App Engine in 40 minutes (the absolute essentials) (20)

Más de Python Ireland

Más de Python Ireland (17)

Último

Último (20)

Google App Engine in 40 minutes (the absolute essentials)