Notes for ricecooker library developers¶

Supported Python Versions for Chefs¶

All chefs written need to support either Python 3.4 or 3.5.

If you need a module or need to use syntax that is only available in newer Python versions, please get in touch.

Computed identifiers¶

Channel ID¶

The channel_id (uuid hex str) property is an important identifier that:

Is used in the wire formats used to communicate between ricecooker and Kolibri Studio
Appears as part of URLs for on both Kolibri Studio and Kolibri
Determines the filename for the channel sqlite3 database file that Kolibri imports from Kolibri Studio.

To compute the channel_id, you need to know the channel’s source_domain (a.k.a. channel_info['CHANNEL_SOURCE_DOMAIN']) and the channel’s source_id (a.k.a channel_info['CHANNEL_SOURCE_ID']):

import uuid
channel_id = uuid.uuid5(
    uuid.uuid5(uuid.NAMESPACE_DNS, source_domain),
    source_id
).hex

This above code snippet is useful if you know the source_domain and source_id and you want to determine the channel_id without crating a ChannelNode object.

The ChannelNode class implements the following methods:

class ChannelNode(Node):
    def get_domain_namespace(self):
        return uuid.uuid5(uuid.NAMESPACE_DNS, self.source_domain)
    def get_node_id(self):
        return uuid.uuid5(self.get_domain_namespace(), self.source_id)

Given a channel object ch, you can find its id using channel_id = ch.get_node_id().hex.

Node IDs¶

Content nodes within the Kolibri ecosystem have the following identifiers:

source_id (str): arbitrary string used to identify content item within the source website, e.g., the a database id or URL.
node_id (uuid): an identifier for the content node within the channel tree
content_id (uuid): an identifier derived from the channel source_domain and the content node’s source_id used for tracking a user interactions with the content node (e.g. video watched, or exercise completed).

When a particular piece of content appears in multiple channels, or in different places within a tree, the node_id of each occurrence will be different, but the content_id of each item will be the same for all copies. In other words, the content_id keeps track of the “is identical to” information about content nodes.

Content nodes inherit from the TreeNode class, which implements the following methods:

class TreeNode(Node):
    def get_domain_namespace(self):
        return self.domain_ns if self.domain_ns else self.parent.get_domain_namespace()
    def get_content_id(self):
        return uuid.uuid5(self.get_domain_namespace(), self.source_id)
    def get_node_id(self):
        return uuid.uuid5(self.parent.get_node_id(), self.get_content_id().hex)

The content_id identifier is computed based on the channel source domain, and the source_id attribute of the content node. To find the content_id hex value for a content node node, use content_id = node.get_content_id().hex.

The node_id of a content nodes within a tree is computed based on the parent node’s node_id and current node’s content_id.