Open Publication Distribution System

Last updated
Open Publication Distribution System
Internet media type
application/atom+xml;profile=opds-catalog
Initial release5 May 2010 (2010-05-05)
Latest release
OPDS 1.2
11 November 2018;3 years ago (2018-11-11)
Type of format web syndication
Extended from Atom
Open format?Yes
Website opds.io

The Open Publication Distribution System (OPDS) catalog format is a syndication format for electronic publications based on Atom and HTTP. OPDS catalogs enable the aggregation, distribution, discovery, and acquisition of electronic publications. OPDS catalogs use existing or emergent open standards and conventions, with a priority on simplicity.

Contents

The Open Publication Distribution System specification is prepared by an informal grouping of partners, combining Internet Archive, O'Reilly Media, Feedbooks, OLPC, and others.

History

OPDS is based on the initial work done by Lexcycle, the company behind Stanza, [1] an eBook reader application for iOS.[ citation needed ] All revisions of the specification were produced by an informal group organized around an open mailing list. [2]

Version history [3]
VersionDate
Older version, yet still maintained: 0.9 [4] May 25, 2010
Older version, yet still maintained: 1.0 [5] August 30, 2010
Older version, yet still maintained: 1.1 [6] June 27, 2011
Current stable version:1.2 [7] November 11, 2018
Future release: 2.0 [8] ?
Legend:
Old version
Older version, still maintained
Latest version
Latest preview version
Future release

OPDS software

Many e-readers or e-book reading applications support importing books from an OPDS catalog. E-book management applications such as Calibre also often include OPDS server software to make an e-book collection available through an OPDS catalog.

Example of OPDS 1.1 content

An example of an acquisition feed in OPDS:

<?xml version="1.0" encoding="UTF-8"?><feedxmlns="http://www.w3.org/2005/Atom"xmlns:dc="http://purl.org/dc/terms/"xmlns:opds="http://opds-spec.org/2010/catalog"><id>urn:uuid:433a5d6a-0b8c-4933-af65-4ca4f02763eb</id><linkrel="related"href="/opds-catalogs/vampire.farming.xml"type="application/atom+xml;profile=opds-catalog;kind=acquisition"/><linkrel="self"href="/opds-catalogs/unpopular.xml"type="application/atom+xml;profile=opds-catalog;kind=acquisition"/><linkrel="start"href="/opds-catalogs/root.xml"type="application/atom+xml;profile=opds-catalog;kind=navigation"/><linkrel="up"href="/opds-catalogs/root.xml"type="application/atom+xml;profile=opds-catalog;kind=navigation"/><title>Unpopular Publications</title><updated>2010-01-10T10:01:11Z</updated><author><name>Spec Writer</name><uri>http://opds-spec.org</uri></author><entry><title>Bob, Son of Bob</title><id>urn:uuid:6409a00b-7bf2-405e-826c-3fdff0fd0734</id><updated>2010-01-10T10:01:11Z</updated><author><name>Bob the Recursive</name><uri>http://opds-spec.org/authors/1285</uri></author><dc:language>en</dc:language><dc:issued>1917</dc:issued><categoryscheme="http://www.bisg.org/standards/bisac_subject/index.html"term="FIC020000"label="FICTION / Men's Adventure"/><summary>The story of the son of the Bob and the gallant part he played in       the lives of a man and a woman.</summary><linkrel="http://opds-spec.org/image"href="/covers/4561.lrg.png"type="image/png"/><linkrel="http://opds-spec.org/image/thumbnail"href="/covers/4561.thmb.gif"type="image/gif"/><linkrel="alternate"href="/opds-catalogs/entries/4571.complete.xml"type="application/atom+xml;type=entry;profile=opds-catalog"title="Complete Catalog Entry for Bob, Son of Bob"/><linkrel="http://opds-spec.org/acquisition"href="/content/free/4561.epub"type="application/epub+zip"/><linkrel="http://opds-spec.org/acquisition"href="/content/free/4561.mobi"type="application/x-mobipocket-ebook"/></entry><entry><title>Modern Online Philately</title><id>urn:uuid:7b595b0c-e15c-4755-bf9a-b7019f5c1dab</id><author><name>Stampy McGee</name><uri>http://opds-spec.org/authors/21285</uri></author><author><name>Alice McGee</name><uri>http://opds-spec.org/authors/21284</uri></author><author><name>Harold McGee</name><uri>http://opds-spec.org/authors/21283</uri></author><updated>2010-01-10T10:01:10Z</updated><rights>Copyright (c) 2009, Stampy McGee</rights><dc:identifier>urn:isbn:978029536341X</dc:identifier><dc:publisher>StampMeOnline, Inc.</dc:publisher><dc:language>en</dc:language><dc:issued>2009-10-01</dc:issued><contenttype="text">The definitive reference for the web-curious       philatelist.</content><linkrel="http://opds-spec.org/image"href="/covers/11241.lrg.jpg"type="image/jpeg"/><linkrel="http://opds-spec.org/acquisition/buy"href="/content/buy/11241.epub"type="application/epub+zip"><opds:pricecurrencycode="USD">18.99</opds:price><opds:pricecurrencycode="GBP">11.99</opds:price></link></entry></feed>

OPDS catalogs

Dozens of OPDS catalogs are available online, and in many different languages. [9]

Many users of OPDS also create their own OPDS catalog, as a way to access their ebooks from any device. [10]

Developers implementing an OPDS catalog usually use the Feedbooks catalog [11] as an example of a fully featured catalog. An OPDS validator is also available to test OPDS feeds. [12]

Related Research Articles

A document type definition (DTD) is a set of markup declarations that define a document type for an SGML-family markup language.

Atom (web standard) Web standards

The name Atom applies to a pair of related Web standards. The Atom Syndication Format is an XML language used for web feeds, while the Atom Publishing Protocol is a simple HTTP-based protocol for creating and updating web resources.

XML Linking Language, or XLink, is an XML markup language and W3C specification that provides methods for creating internal and external links within XML documents, and associating metadata with those links.

XML namespaces are used for providing uniquely named elements and attributes in an XML document. They are defined in a W3C recommendation. An XML instance may contain element or attribute names from more than one XML vocabulary. If each vocabulary is given a namespace, the ambiguity between identically named elements or attributes can be resolved.

The Sitemaps protocol allows a webmaster to inform search engines about URLs on a website that are available for crawling. A Sitemap is an XML file that lists the URLs for a site. It allows webmasters to include additional information about each URL: when it was last updated, how often it changes, and how important it is in relation to other URLs of the site. This allows search engines to crawl the site more efficiently and to find URLs that may be isolated from the rest of the site's content. The Sitemaps protocol is a URL inclusion protocol and complements robots.txt, a URL exclusion protocol.

FeedSync for Atom and RSS, previously Simple Sharing Extensions, are extensions to RSS and Atom feed formats designed to enable the synchronization of information by using a variety of data sources. Initially developed by Ray Ozzie, Chief Software Architect at Microsoft, it is now maintained by Jack Ozzie, George Moromisato, Matt Augustine, Paresh Suthar and Steven Lees. Dave Winer, the designer of the UserLand Software RSS specification variants, has given input for the specifications.

GRDDL is a markup format for Gleaning Resource Descriptions from Dialects of Languages. It is a W3C Recommendation, and enables users to obtain RDF triples out of XML documents, including XHTML. The GRDDL specification shows examples using XSLT, however it was intended to be abstract enough to allow for other implementations as well. It became a Recommendation on September 11, 2007.

RDFa or Resource Description Framework in Attributes is a W3C Recommendation that adds a set of attribute-level extensions to HTML, XHTML and various XML-based document types for embedding rich metadata within Web documents. The Resource Description Framework (RDF) data-model mapping enables its use for embedding RDF subject-predicate-object expressions within XHTML documents. It also enables the extraction of RDF model triples by compliant user agents.

Metalink File format that describes one or more computer files available for download

Metalink is an extensible metadata file format that describes one or more computer files available for download. It specifies files appropriate for the user's language and operating system; facilitates file verification and recovery from data corruption; and lists alternate download sources.

In computer science and web development, XML Events is a W3C standard for handling events that occur in an XML document. These events are typically caused by users interacting with the web page using a device, such as a web browser on a personal computer or mobile phone.

GeoRSS is a specification for encoding location as part of a Web feed. (Web feeds are used to describe feeds of content, such as news articles, Audio blogs, video blogs and text blog entries. These web feeds are rendered by programs such as aggregators and web browsers.) The name "GeoRSS" is derived from RSS, the most known Web feed and syndication format.

The Web Application Description Language (WADL) is a machine-readable XML description of HTTP-based web services. WADL models the resources provided by a service and the relationships between them. WADL is intended to simplify the reuse of web services that are based on the existing HTTP architecture of the Web. It is platform and language independent and aims to promote reuse of applications beyond the basic use in a web browser. WADL was submitted to the World Wide Web Consortium by Sun Microsystems on 31 August 2009, but the consortium has no current plans to standardize it. WADL is the REST equivalent of SOAP's Web Services Description Language (WSDL), which can also be used to describe REST web services.

XML documents typically refer to external entities, for example the public and/or system ID for the Document Type Definition. These external relationships are expressed using URIs, typically as URLs.

EPUB E-book file format

EPUB is an e-book file format that uses the ".epub" file extension. The term is short for electronic publication and is sometimes styled ePub. EPUB is supported by many e-readers, and compatible software is available for most smartphones, tablets, and computers. EPUB is a technical standard published by the International Digital Publishing Forum (IDPF). It became an official standard of the IDPF in September 2007, superseding the older Open eBook (OEB) standard.

The Office Open XML file formats are a set of file formats that can be used to represent electronic office documents. There are formats for word processing documents, spreadsheets and presentations as well as specific formats for material such as mathematical formulae, graphics, bibliographies etc.

In computing, Open Data Protocol (OData) is an open protocol that allows the creation and consumption of queryable and interoperable REST APIs in a simple and standard way. Microsoft initiated OData in 2007. Versions 1.0, 2.0, and 3.0 are released under the Microsoft Open Specification Promise. Version 4.0 was standardized at OASIS, with a release in March 2014. In April 2015 OASIS submitted OData v4 and OData JSON Format v4 to ISO/IEC JTC 1 for approval as an international standard. In December 2016, ISO/IEC published OData 4.0 Core as ISO/IEC 20802-1:2016 and the OData JSON Format as ISO/IEC 20802-2:2016.

XHTML+RDFa is an extended version of the XHTML markup language for supporting RDF through a collection of attributes and processing rules in the form of well-formed XML documents. XHTML+RDFa is one of the techniques used to develop Semantic Web content by embedding rich semantic markup. Version 1.1 of the language is a superset of XHTML 1.1, integrating the attributes according to RDFa Core 1.1. In other words, it is an RDFa support through XHTML Modularization.

The Salmon Protocol is a message exchange protocol running over HTTP designed to decentralize commentary and annotations made against newsfeed articles such as blog posts. It allows a single discussion thread to be established between the article's origin and any feed reader or "aggregator" which is subscribing to the content. Put simply, that if an article appeared on 3 sites: A, B and C, that members of all 3 sites could see and contribute to a single thread of conversation regardless of site they were viewing from.

Really Simple Discovery (RSD) is an XML format and a publishing convention for making services exposed by a blog, or other web software, discoverable by client software.

Hypertext Application Language (HAL) is an Internet Draft standard convention for defining hypermedia such as links to external resources within JSON or XML code. The standard was initially proposed in June 2012 specifically for use with JSON and has since become available in two variations, JSON and XML. The two associated MIME types are media type: application/hal+xml and media type: application/hal+json.

References

  1. Fahlgren, Keith (April 9, 2009). "Project Goals". Open Publication Distribution System (Mailing list). Retrieved May 5, 2013 via Google Groups.
  2. "Open Publication Distribution System". Google Groups. Retrieved May 5, 2013.
  3. "Specifications". Open Publication Distribution System: Official Specification & Blog. Retrieved December 4, 2017.
  4. "OPDS Catalog 0.9" . Retrieved May 5, 2013.
  5. "OPDS Catalog 1.0" . Retrieved May 5, 2013.
  6. "OPDS Catalog 1.1" . Retrieved May 5, 2013.
  7. "OPDS Catalog 1.2" . Retrieved November 11, 2018.
  8. "OPDS Catalog 2.0" . Retrieved November 11, 2018.
  9. "Online OPDS Catalogs". MobileRead Wiki. Retrieved 2011-05-19.
  10. "OPDS Catalog Generation". MobileRead Wiki. Retrieved 2011-05-19.
  11. "Feedbooks OPDS Catalog". Feedbooks. Retrieved 2011-05-19.
  12. "OPDS Validator" . Retrieved 2011-05-19.

OPDS standard

OPDS working group links

Other resources