Background
OPDS 2.0 is based on the Readium Web Publication Manifest model and JSON-LD, with a focus on aggregating publications together in order to facilitate their distribution. Compared to previous versions of the OPDS specification:
1) the model allows multiple collections to be contained in a single feed,
2) the Link Object model is more powerful than the link element in Atom, it supports URI templates and multiple relations,
3) metadata are expressed in JSON but an RDF graph can be extracted using a JSON-LD context,
4) the core metadata vocabulary is tied to schema.org instead of Dublin Core.
https://drafts.opds.io/opds-2.0#overview
Example Feed Tree Structure
Authentication for ODPS - This specification, defines a standard way for OPDS Catalog providers and clients to:
1) provide relevant information for clients to display an authentication page,
2) expose how a client can authenticate using various Authentication Flows. The primary objective is to allow access to specific feeds (such as a bookshelf and subscriptions) along with support for interactions that require authentication (specific acquisition links such as buy, borrow and subscribe).
https://drafts.opds.io/authentication-for-opds-1.0
Example Feed "Tree"
Example Feeds
Root Feed
The Root feed can contain Publication Feeds or Navigation Feeds depending on how large or organized a distributors collection happens to be.
SAMPLE Open Access Publications
In this example, the Collection is for Open Access Publications. The feed uses rel links to supports paging as well as provide metadata as to the number of items in the collection and the number of pages comprising the feed. This facilitates client processing of the metadata and metadata crawlers.
SAMPLE Navigation Feed for DRM Publications
SAMPLE DRM Protected Publication Collection{