Kalpa

Kalpa provides a starting point for resource traversal in Pyramid. It provides two classes for this, a Branch and a Leaf, which allow you to create arbitrary resource trees without the boilerplate.

There is also a Root class for added convenience that accepts a request during initialization. This can be used to create a starting point for Pyramid's traversal.

from kalpa import Root, Node, branch

USERS = {...}


class Root(Root):
    """Root resource for Pyramid traversal."""
    users = branch('UserCollection')


class UserCollection(Node):
    """User collection, for listings, or loading single users."""
    __child_cls__ = 'User'

    def __load__(self, key):
        """Returns dict with attributes to create a child node from."""
        return {'user': USERS[key]}  # Load user or raise KeyError.


class User(Node):
    """User resource, a single loaded user."""
    gallery = branch('UserGallery', aliases=['images'])


class UserGallery(Node):
    """Gallery of images posted by a user.

    Reachable as `/users/:id/gallery` but also `/users/:id/images`.
    """