Example uses of Kalpa

declarative.py

from kalpa import Root, Node, branch

USERS = {...}


class Root(Root):
    """Traversal root for Pyramid application."""
    users = branch('UserCollection')


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

    def __load__(self, key):
        """Return child resource with requested user included."""
        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`.
    """

imperative.py

from kalpa import Root, Branch, Leaf

USERS = {...}


@Root.attach('users')
class UserCollection(Branch):
    """User collection, for listings, or loading single users."""

    def __load__(self, key):
        """Return child resource with requested user included."""
        user = USERS[key]  # Load user or raise KeyError.
        return self._child(key, user=user)


@UserCollection.child_resource
class User(Branch):
    """User resource, a single loaded user."""


@User.attach('gallery', aliases=['images'])
class UserGallery(Leaf):
    """Gallery of images posted by a user.

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