Khufu-SQLAHelper 0.4a3

Khufu component for using SQLAlchemy with Pyramid

Requirements Satisfied by Installing

• Pyramid
• SQLAlchemy
• zope.sqlalchemy
• repoze.tm2
• transaction
• pyramid_traversalwrapper

NOTE 1: The SQLAHelper middleware includes the repoze.tm2 middleware NOTE 2: The SQLAHelper middleware requires that the app being wrapped was generated by Pyramid

Database Configuration

To use SQLAHelper database configuration there are two steps:

1. Hook up the configuration via configurator.include('khufu.sqlahelper')
2. Wrap the web app in the SQLAHelper middleware with khufu.sqlahelper.with_db(pyramid_app)

Once inside a SQLAHelper-wrapped application, the database session is accessed via request.db.

An example which sets up a new wsgi app wrapped in the sqlahelper middlewares... the database connection is built based on the sqlalchemy.url value:

config = Configurator(root_factory=models.get_root,
                      settings={'sqlalchemy.url': 'sqlite://:memory'})
config.include('khufu.sqlahelper')
app = sqlahelper.with_db(config.make_wsgi_app())

Once inside view code, database queries can happen as follows:

@view_config(context=models.SomeContainerModel)
def users_view(request):
    return {'models': request.db.query(models.SomeModel).all()}

NOTE: view code should never manually commit the ``request.db`` object, please use the transaction api directly if this is required

Database Traversal Utils

The following provides traversal as follows:

/                                 # Root
/distros/                         # Distribution container
/distros/foobar                   # Distribution called foobar
/distros/foobar/versions/         # Versions container for foobar
/distros/foobar/versions/0.1      # Version 0.1 of foobar

The example code is as follows:

from pysoftcenter import models
from pysoftcenter.traversalutils import (DataContainer,
                                         attrs_traversable,
                                         TraversalMixin)

class DistroVersionContainer(DataContainer):
    model_class = models.DistroVersion
    unique_lookup = 'version'

@attrs_traversable(versions=DistroVersionContainer)
class DistroDataContainer(DataContainer):
    model_class = models.Distro

class Root(TraversalMixin, dict):
    def __init__(self, db):
        TraversalMixin.__init__(self, db=db)
        self['distros'] = DistroDataContainer('distros', self)

def get_root(request):
    root = Root(request.db)
    return root

0.4a3 (Feb-16,2011)

• Updated project url's

0.4a2 (Feb-11-2011)

• Fixed small issue where decorator wasn't working

0.4a1 (Feb-10-2011)

• Added traversalutils for helping expose SQL-based models using traversal

0.3 (Feb-04-2011)

• Changed with_db api to make db param optional
• Updated docs

0.2.1 (Jan-17-2011)

• Added use_zope_tm option to get_session_factory

0.2 (Jan-9-2011)

• first release