Storm ORM by Canonical in WSGI enabled applications

sevkin (Vsevolod Balashov) — Fri, 10 Aug 2007 11:39:51 GMT


#!/usr/bin/env python

# vim:ts=4:sw=4:et

# (c) 2007 Vsevolod Balashov  under terms of LGPL 2.1

# use Storm ORM  in WSGI enabled applications

#

# actual version on http://pypi.python.org/pypi/middlestorm



"""WSGI middleware for Storm.



This is the database access inteface for WSGI enabled (PEP 333) web applications.



Pylons framework example:



in wsgiapp.py



from storm.database import create_database

from middlestorm import MiddleStorm

...



# CUSTOM MIDDLEWARE HERE

app = MiddleStorm(app, create_database(config['app_conf']['sqlalchemy.default.uri']))



in controller:



class DemoController(BaseController):

    def index(self):

        store = request.environ['storm.store']

        ...

"""



from storm.database import Database

from storm.store import Store

from threading import local



__all__ = ["MiddleStorm"]

__author__ = "Vsevolod Balashov "

__version__ = "0.1"



class SingleConn(Database):

    """Database proxy class.

    Share single database connection between all Store object instances in threads.

    If you have readonly database or not use transactions why not?

    """

    def __init__(self, database):

        self._database = database

        self._connection = database.connect()

    def connect(self):

        return self._connection



class MiddleStorm(object):

    """WSGI middleware.

    Add Store object instance in environ['storm.store']. Each thread contains own instance.

    """



    def __init__(self, app, database, single = False):

        """Create WSGI middleware.

        @param app: up level application or middleware.

        @param database: instance of Database returned create_database.

        @param: single: use single database connection in all threads. 

        """

        assert isinstance(database, Database), \

            'database must be subclass of storm.database.Database'

        if single:

            self._database = SingleConn(database)

        else:

            self._database = database

        self._app = app

        self._local = local()



    def __call__(self, environ, start_response):

        try:

            environ['storm.store']  = self._local.store

        except AttributeError:

            environ['storm.store']  = \

                self._local.__dict__.setdefault('store', Store(self._database))

        return self._app(environ, start_response)
DZone Snippets: orm code

Storm ORM by Canonical in WSGI enabled applications
