Extending OPDS

Hadrien GardeurFeedbooks

OPDS is an extension

Basic OPDS catalog

Atom feedsSame requirements than an Atom entry atom:title atom:author atom:id atom:updated

If it’s a publication, the requirement is at least one acquisition link.

element atom:entry { atomCommonAttributes, (atomAuthor* & atomCategory* & atomContent? & atomContributor* & atomId & atomLink* & atomPublished? & atomRights? & atomSource? & atomSummary? & atomTitle& atomUpdated & extensionElement*)

}

Scary but Cool stuff

Cool !

Metadata

AtomDublinCore Terms (dcterms:issued)

Prism (prism:issue)

New attributes in the OPDS namespace(opds:price, opds:gateway)

Link Relations

For feed-level or entry-level linksGive a meaning to what you’re linking toDifferent type, different meaning

In OPDS we use:1. Link relations from the IANA link registry Link header draft2. Our own link relations (http://opds-spec.org/relation)

Why ?

More Metadata

Support new type of publications Provide more and better information… without affecting the user experience on mobile devices

More meaningful links

New Features

Comments (implemented on Feedbooks)

ReviewsAnnotations Publishing (implemented on Feedbooks)

OPDS shopping cart

How ?

Partial & Full Entries

Like in AtomPub, you shouldn’t assume that an entry in a collection feed is a full entry

A partial entry can link to a full entry<atom:link rel="alternate" type= "application/atom+xml;type=entry" href=" …" />

Required & Recommended metadata MUST be in partialYou can add anything you want in full entries

New Link Relations

Use link relations from the Link Header draftNew features in OPDS: http://opds-spec.org/relationCreate your own: http://mydomain.com/relation

Associate a link with a new type… or media parameters in a type

Use AtomPub !

Don’t limit yourself to GET requests !CRUD with POST, GET, UPDATE and DELETE

AtomPub = Service Documents, Workspaces and Collections

New link relations: edit, edit-media

Example: Comments

On Feedbooks

Based on the Atom Threading Extension Link Relations: replies, in-reply-toAttributes: thr:count, thr:updated

AtomPub to POST comment (no UPDATE or DELETE)

In our entries

Nothing in the partial entry, MUST GET full entry

<atom:link rel="replies" thr:count="2" thr:updated="…" />

thr:count gives the total number of comments thr:updated is the timestamp for the last update (last comment)

Collection feed for Comments

A comment is a normal Atom entry atom:author for the user atom:content for the comment

app:collection to POST content (no service document) href attribute for the URI app:accept to list the types (application/atom+xml;type=entry)

Best Practices

Don’t create stuff on your own search for RFCs read and participate on mailing lists: atom-syntax, atom & opdsUse the IANA link registry and Link Header draft

Use link relationsMetadata not included in the specs MUST be in the full entry

That’s all folks !