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Minimal Hello World Example WebapplicationΒΆ

This buildout uses WebOb to help creating a minimal WSGI application.

Create a minimal filesystem structure:

cd /PATH/TO/EXAMPLE
mkdir --parents src/helloworld
touch src/helloworld/__init__.py
wget http://python-distribute.org/bootstrap.py

Add file buildout.cfg containing:

[buildout]
parts = helloworld
develop = .

[helloworld]
recipe = zc.recipe.egg:scripts
egg = helloworld

Add file setup.py:

from setuptools import setup, find_packages
setup(name='helloworld',
      packages=find_packages('src'),
      package_dir = {'': 'src'},
      install_requires=['setuptools', 'yafowil.webob'],
      entry_points = """\
      [console_scripts]
      helloworld = helloworld.run:run
      """
)

Add src/helloworld/run.py including a minimal web application, the YAFOWIL form and a dumb filesystem based storage:

from yafowil import loader
import yafowil.webob
from yafowil.base import factory
from yafowil.controller import Controller
from webob import Request, Response

address, port = '127.0.0.1', 8080
url = 'http://%s:%s/' % (address, port)

def store(widget, data):
    with open('helloworld.txt', 'a') as storage:
        storage.write(data.fetch('helloworld.hello').extracted + '\n')

def readall():
    try:
        with open('helloworld.txt', 'r') as storage:
            return reversed(storage.readlines())
    except IOError:
        return ['Empty storage!']

def next(request):
    return url

def application(environ, start_response):
    request = Request(environ)
    response = Response()
    response.write('<html><body><h1>YAFOWIL Demo</h1>')
    form = factory(u'form', name='helloworld', props={
        'action': url})
    form['hello'] = factory('field:label:error:text', props={
        'label': 'Enter some text',
        'value': '',
        'required': True})
    form['submit'] = factory('field:submit', props={
        'label': 'store value',
        'action': 'save',
        'handler': store,
        'next': next})
    controller = Controller(form, request)
    response.write(controller.rendered)
    response.write('<hr />%s</html></body>' % '<br />'.join(readall()))
    return response(environ, start_response)

def run():
    from wsgiref.simple_server import make_server
    server = make_server(address, port, application)
    server.serve_forever()

Now bootstrap and run buildout, and start the application.:

python2.6 bootstrap.py
./bin/buildout
./bin/helloworld

Pointing the browser to http://localhost:8080/ shows the application.

The full working example code is at github available.