rene-armida/paste_wsgi_example.py

## paste_wsgi_example.py
'''
A minimal example of how to use Paste and WebOb to build a custom
WSGI app and serve it.

Depends on:
* paste - http://pypi.python.org/pypi/Paste
* webob - http://pypi.python.org/pypi/WebOb/1.1.1
* routes - http://pypi.python.org/pypi/Routes/1.12.3

I (marmida) still think this is less appropriate than using CouchDB; you'll need
to handle routing and controllers manually to reproduce Couch's default behavior
(a RESTful interface to db records).

I extracted this from an app I was working on a while ago:
https://github.com/marmida/catalog/blob/master/server/app.py

I originally built that code to work with neo4j, and then switched to sqlite.
At the time, neo4j required thread isolation; I kept that after I moved to sqlite.
If you find yourself hitting threading issues (e.g. sqlite doesn't like being
called from paste worker threads), you can look at my code on GitHub for a solution.
'''

import paste.fileapp
import paste.httpserver
import routes
import webob
import webob.dec
import webob.exc


HOST = '127.0.0.1'
PORT = 8080

class ExampleApp(object):
    '''
    A WSGI "application."

    See: http://pythonpaste.org/do-it-yourself-framework.html#writing-a-wsgi-application
    '''

    # Our routes map URIs to methods of this app, and define how to extract args from requests
    # Complaint: in order to make this RESTful, you have to plan routes yourself
    map = routes.Mapper()
    map.connect('index', '/', method='index')
    map.connect('greet', '/greet/{name}', method='greet')

    @webob.dec.wsgify
    def __call__(self, req):
        '''
        Glue.  A WSGI app is a callable; thus in order to make this object an application,
        we define __call__ to make it callable.  We then ask our Mapper to do some routing,
        and dispatch to the appropriate method.  That method must return a webob.Response.
        '''
        results = self.map.routematch(environ=req.environ)
        if not results:
            return webob.exc.HTTPNotFound()
        match, route = results
        link = routes.URLGenerator(self.map, req.environ)
        req.urlvars = ((), match)
        kwargs = match.copy()
        method = kwargs.pop('method')
        req.link = link
        return getattr(self, method)(req, **kwargs)

    def index(self, req):
        '''
        Controller #1: a landing page.
        '''
        return webob.Response(
            body='''<html><body>
                    <p>Your name:
                        <form onSubmit="location.href='/greet/' + encodeURI(document.getElementById('name_input').value); return false;">
                            <input type="text" value="" id="name_input"/>
                        </form>
                    </p>
                </body></html>'''
        )

    def greet(self, req, name=None):
        '''
        Controller #2: do something with a URI arg to show dynamic behavior.
        '''
        return webob.Response(
            body='<html><body>Dear %s, you\'re a shmuck.</body></html>' % name
        )

def main():
    '''
    CLI entry point.
    '''
    paste.httpserver.serve(ExampleApp(), host=HOST, port=PORT)

# for importability, don't run main() unless we really mean to
if __name__ == '__main__':
    main()
	'''
	A minimal example of how to use Paste and WebOb to build a custom
	WSGI app and serve it.

	Depends on:
	* paste - http://pypi.python.org/pypi/Paste
	* webob - http://pypi.python.org/pypi/WebOb/1.1.1
	* routes - http://pypi.python.org/pypi/Routes/1.12.3

	I (marmida) still think this is less appropriate than using CouchDB; you'll need
	to handle routing and controllers manually to reproduce Couch's default behavior
	(a RESTful interface to db records).

	I extracted this from an app I was working on a while ago:
	https://github.com/marmida/catalog/blob/master/server/app.py

	I originally built that code to work with neo4j, and then switched to sqlite.
	At the time, neo4j required thread isolation; I kept that after I moved to sqlite.
	If you find yourself hitting threading issues (e.g. sqlite doesn't like being
	called from paste worker threads), you can look at my code on GitHub for a solution.
	'''

	import paste.fileapp
	import paste.httpserver
	import routes
	import webob
	import webob.dec
	import webob.exc


	HOST = '127.0.0.1'
	PORT = 8080

	class ExampleApp(object):
	'''
	A WSGI "application."

	See: http://pythonpaste.org/do-it-yourself-framework.html#writing-a-wsgi-application
	'''

	# Our routes map URIs to methods of this app, and define how to extract args from requests
	# Complaint: in order to make this RESTful, you have to plan routes yourself
	map = routes.Mapper()
	map.connect('index', '/', method='index')
	map.connect('greet', '/greet/{name}', method='greet')

	@webob.dec.wsgify
	def __call__(self, req):
	'''
	Glue. A WSGI app is a callable; thus in order to make this object an application,
	we define __call__ to make it callable. We then ask our Mapper to do some routing,
	and dispatch to the appropriate method. That method must return a webob.Response.
	'''
	results = self.map.routematch(environ=req.environ)
	if not results:
	return webob.exc.HTTPNotFound()
	match, route = results
	link = routes.URLGenerator(self.map, req.environ)
	req.urlvars = ((), match)
	kwargs = match.copy()
	method = kwargs.pop('method')
	req.link = link
	return getattr(self, method)(req, **kwargs)

	def index(self, req):
	'''
	Controller #1: a landing page.
	'''
	return webob.Response(
	body='''<html><body>
	<p>Your name:
	<form onSubmit="location.href='/greet/' + encodeURI(document.getElementById('name_input').value); return false;">
	<input type="text" value="" id="name_input"/>
	</form>
	</p>
	</body></html>'''
	)

	def greet(self, req, name=None):
	'''
	Controller #2: do something with a URI arg to show dynamic behavior.
	'''
	return webob.Response(
	body='<html><body>Dear %s, you\'re a shmuck.</body></html>' % name
	)

	def main():
	'''
	CLI entry point.
	'''
	paste.httpserver.serve(ExampleApp(), host=HOST, port=PORT)

	# for importability, don't run main() unless we really mean to
	if __name__ == '__main__':
	main()