Device Description Repository: Difference between revisions

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The '''Device Description Repository''' (DDR) is a concept proposed by the [[MWIMobile Web|Mobile Web Initiative]] [[W3C_Device_Description_Working_GroupW3C Device Description Working Group|Device Description Working Group]] (DDWG) of the [[World Wide Web Consortium]]. The DDR is supported by a standard interface and an initial core vocabulary of device properties. Implementations of the proposed repository wouldare expected to contain information about Web-enabled devices (particularly mobile devices). Authors of Web content wouldwill be able to make use of the repositoryrepositories to adapt their content to best suit the requesting device. As such itThis wouldwill facilitate the interaction and viewing of Web pages across devices with widely varying capabilities.

{{no references|date=December 2007}}

==Introduction==

The '''Device Description Repository''' is a concept proposed by the [[MWI|Mobile Web Initiative]] [[W3C_Device_Description_Working_Group|Device Description Working Group]] (DDWG) of the [[World Wide Web Consortium]]. The proposed repository would contain information about Web-enabled devices (particularly mobile devices). Authors of Web content would be able to make use of the repository to adapt their content to best suit the requesting device. As such it would facilitate the interaction and viewing of Web pages across devices with widely varying capabilities.

Information in thea repository wouldshould include information such as the screen dimensions, input mechanisms, supported colors, known limitations, special capabilities etc.

==Status==

The "requirements for a single logical device descriptions repository"<ref>{{cite web|author=David Sanders|title=Device Description Repository Requirements 1.0 (Draft)|url=http://www.w3.org/TR/2006/WD-DDR-requirements-20060410/|date=[[April 10]], [[2006]]|publisher=W3C (MIT, ERCIM, Keio)|accessdate=2007-12-10}}</ref> were first published as a W3C Working Draft in April 2006, and completed as a "Working Group Note"<ref>{{cite web|author=Kevin Smith|title=Device Description Repository Requirements 1.0|url=http://www.w3.org/TR/2007/NOTE-DDR-requirements-20071217/|date=[[December 17]],[[ 2007]]|publisher=W3C (MIT, ERCIM, Keio)|accessdate=2008-04-09}}</ref> in December 2007.

The "DDR SimpleCore APIVocabulary"<ref>{{cite web|authorauthor1=Jo Rabin, José|author2=Andrea Manuel Cantera Fonseca,Trasatti |author3=Rotan Hanrahan, Ignacio Marín|title=Device Description Repository SimpleCore APIVocabulary (Note)|url=http://www.w3.org/TR/2008/WDNOTE-DDRddr-Simplecore-APIvocabulary-2008040420080414/|date=[[April 4]]14,[[ 2008]]|publisher=W3C (MIT, ERCIM, Keio)|accessdate=2008-0412-0912}}</ref> specification was published asin aApril Working2008. DraftIt illustrates how to create definitions of aproperties proposedthat W3Ccan Recommendationbe used in Aprilconjunction 2008with the DDR Simple API.

The "DDR Simple API"<ref>{{cite web|author1=Jo Rabin |author2=José Manuel Cantera Fonseca |author3=Rotan Hanrahan |author4=Ignacio Marín |title=Device Description Repository Simple API|url=http://www.w3.org/TR/2008/REC-DDR-Simple-API-20081205/|date=December 5, 2008|publisher=W3C (MIT, ERCIM, Keio)|accessdate=2008-12-12}}</ref> specification was published as a [[W3C recommendation|W3C Recommendation]] in December 2008.

The DDWG formally closed in December 2008. The Chair and volunteers agreed to maintain the DDWG home page and wiki after this time,<ref>{{cite web|author=Rotan Hanrahan|title=Device Description Repository Simple API is a W3C Recommendation (closing message from Chair)|url=http://lists.w3.org/Archives/Public/public-ddwg/2008Dec/0000.html|date=December 8, 2008|accessdate=2008-12-12}}</ref> to answer questions and encourage implementations.

==Background==

The idea of implementing a Device Description Repository was discussed at an international workshop<ref>{{cite web|title=International Workshop on the Implementation of a Device Description Repository|url=http://www.w3.org/2005/MWI/DDWG/workshop2006/|date=[[July 12]],[[ 2006]]|publisher=W3C (MIT, ERCIM, Keio)|accessdate=2008-04-09}}</ref> held by the DDWG in Madrid, Spain in July, 2006. This resulted in a proposal to re-charter<ref>{{cite web|title=MWI Device Description Working Group Charter|url=http://www.w3.org/2006/09/mwi-ddwg2-charter|date=[[December 5]],[[ 2006]]|publisher=W3C (MIT, ERCIM, Keio)|accessdate=2008-04-09}}</ref> DDWG to work on the formal design of the programming interfaces, and ways to populate thea repository with data and make this available to anyone who wanted to build Web servers that could adapt content to suit the end user devices.

==Design goals==

The architecture of the repository haswas not been clarifiedprescribed, but a distributed solution isare likely. In general, the desirable characteristics of a Device Description Repository are:

* '''Relevance of data'''. The [[W3C_Device_Description_Working_GroupW3C Device Description Working Group|DDWG]] includes content adaptation specialists who have identified a core set of device properties that are useful for adaptation. Other groups are likely to refine this knowledge. Keeping the information up-to-date will also be a challenge.

* '''Ease of use'''. The interfaces should map easily to a variety of programming languages, and be as simple to use as other popular adaptation technologies (e.g. [[Wurfl|WURFL]http://augur.io/ Augur] {{Webarchive|url=https://web.archive.org/web/20150702141341/http://augur.io/ |date=2015-07-02 }}).

* '''Ease of deployment'''. Existing technologies like [[Domain name system|DNS]] show that global repositories can be deployed on a real-time basis. The W3C is unlikely to specify a particular server architecture. The DDWG has already identified a [[Web_servicesWeb services|Web Service]] interface (e.g. [[SOAP]]) as a minimum requirement, and implementations are free to create the logic any way they wish (e.g. [[RDBMS|relational database]] queries) so long as the formal interface is supported.

* '''Assured interoperability'''. The varied nature of the Web requires that the repository interfaces and data formats can be supported by the largest number of Web technologies. Formal descriptions of [[API|APIs]]s and Data Vocabularies will be necessary.

* '''Assured availability'''. If Web servers rely on device descriptions to provide adapted content, then these descriptions must be available at all times. Multiple repository hosts and support for data caching are likely to be part of the repository architecture.

* '''Efficiency'''. To ensure that the repository does not create unnecessary burden on scarce resources, the load should be distributed and data formats should be designed for simple processing.

* '''Industry support'''. The backing of organisations like W3C and the [[Open Mobile Alliance]], and of vendors, service providers and device manufacturers will be critical.

The interface to the repository should provide the means of retrieving contextual information based on some evidence that identifies the context. Typically this means providing request headers through the interface and subsequently retrieving values for named properties. The W3C [[W3C_Device_Description_Working_GroupW3C Device Description Working Group|DDWG]] is providingproduced an initial vocabulary of such properties (based on a formal ontology), and an interface for the retrieval functionality. The interface will beis designed in a language-neutral manner to enable many implementations on many platforms. The published specification includes samples in Java, IDL and WSDL.

==NotesImplementations==

Open and commercial implementations of the DDR Simple API are available. Some of these formed part of the W3C's implementation report<ref>{{cite web|title=DDR Simple API Implementation Report|url=http://www.w3.org/2005/MWI/DDWG/drafts/api/test-report.html|date=June 19, 2008|publisher=W3C (MIT, ERCIM, Keio)|accessdate=2008-12-12}}</ref> prior to the API becoming a Web standard. The W3C's Mobile Web Initiative also tracks implementations of relevant mobile standards and other developer resources, including the DDR Simple API.

{{reflist}}

On November 4, 2011 during Mobile2Days event<ref>{{cite web|title=Mobile2Days Agenda 2011|url=http://2011.java2days.com/wp-content/uploads/2011/11/Agenda-2011.pdf|date=November 4, 2011|publisher=Java2Days|accessdate=2011-11-04}}</ref> the [http://openddr.mobi OpenDDR] project was launched. It is an open source project aiming to be the reference community implementation of W3C's DDR Simple API and the reference community repository.

In January 2012 [http://devicemap.apache.org/ Apache DeviceMap] became an incubating project at the Apache Software Foundation, and in September 2012 the [http://openddr.mobi OpenDDR] project was [https://issues.apache.org/jira/browse/DMAP-11 donated] to Apache. After Apache DeviceMap had been archived in early 2017, [http://openddr.mobi OpenDDR] was made available again on [[GitHub]].

== Links ==

==See also==

*[[UAProf]]

*[[W3C]]

*[[Wurfl|WURFL]]

==Notes==

== External links ==

{{Reflist|2}}

== External links ==

*[http://www.w3.org/2005/MWI/DDWG/ Device Description Working Group (DDWG)]

*[http://www.w3.org/2005/MWI/DDWG/workshop2006/ DDWG Workshop on the implementation of a DDR]

*[http://www.w3.org/Mobile/ W3C Mobile Web Initiative (MWI)]

*[http://www.w3.org/Mobile/Dev W3C MWI Developer resources]

*[http://www.openmobilealliance.org/ Open Mobile Alliance]

*[https://deviceatlas.com/device-data/devices DeviceAtlas Device Description Repository]

*[http://www.w3.org W3C]

[[Category:World Wide Web Consortium standards]]