RSS enclosure
Encyclopedia
RSS enclosures are a way of attaching multimedia
Multimedia
Multimedia is media and content that uses a combination of different content forms. The term can be used as a noun or as an adjective describing a medium as having multiple content forms. The term is used in contrast to media which use only rudimentary computer display such as text-only, or...

 content to RSS
RSS (file format)
RSS is a family of web feed formats used to publish frequently updated works—such as blog entries, news headlines, audio, and video—in a standardized format...

 feeds
Web feed
A web feed is a data format used for providing users with frequently updated content. Content distributors syndicate a web feed, thereby allowing users to subscribe to it. Making a collection of web feeds accessible in one spot is known as aggregation, which is performed by an aggregator...

 by providing the URL
Uniform Resource Locator
In computing, a uniform resource locator or universal resource locator is a specific character string that constitutes a reference to an Internet resource....

 of a file associated with an entry, such as an MP3
MP3
MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...

 file to a music recommendation or a photo to a diary entry. Unlike e-mail attachment
E-mail attachment
An email attachment is a computer file sent along with an email message. One or more files can be attached to any email message, and be sent along with it to the recipient. This is typically used as a simple method to share documents and images...

s, enclosures are merely hyperlink
Hyperlink
In computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...

s to files, the actual file data is not embedded
Compound document
In computing, a compound document is a document type typically produced using word processing software, and is a regular text document intermingled with non-text elements such as spreadsheets, pictures, digital videos, digital audio, and other multimedia features...

 into the feed (unless a data URL is used). Support and implementation among aggregators varies: if the software understands the specified file format
File format
A file format is a particular way that information is encoded for storage in a computer file.Since a disk drive, or indeed any computer storage, can store only bits, the computer must have some way of converting information to 0s and 1s and vice-versa. There are different kinds of formats for...

, it may automatically download and display the content, otherwise provide a link to it or silently ignore it.

The addition of enclosures to RSS, as first implemented by Dave Winer
Dave Winer
Dave Winer is an American software developer, entrepreneur and writer in New York City. Winer is noted for his contributions to outliners, scripting, content management, and web services, as well as blogging and podcasting...

 in late 2000 http://backend.userland.com/rss092, was an important prerequisite for the emergence of podcast
Podcast
A podcast is a series of digital media files that are released episodically and often downloaded through web syndication...

ing, arguably the most common use of the feature . In podcasts and related technologies enclosures are not merely attachments to entries, but provide the main content of a feed.

Syntax

In RSS 2.0, the syntax for the tag, an optional child of the element, is as follows:

where the value of the url attribute is a URL
Uniform Resource Locator
In computing, a uniform resource locator or universal resource locator is a specific character string that constitutes a reference to an Internet resource....

 of a file, length is its size in byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...

s, and type its mime type.

It is recommended that only one element is included per .http://www.rssboard.org/rss-profile#element-channel-item-enclosure

Similar technologies

The RSS <enclosure> has similarities to:
  • the SMIL
    Synchronized Multimedia Integration Language
    SMIL , the Synchronized Multimedia Integration Language, is a W3C recommended XML markup language for describing multimedia presentations. It defines markup for timing, layout, animations, visual transitions, and media embedding, among other things...

     <prefetch> element,
  • the HTML
    HTML
    HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....

     <link> element with rel="prefetch".http://www.mozilla.org/projects/netlib/Link_Prefetching_FAQ.html
  • the HTTP Link header with rel="prefetch". (See RFC 2068 section 19.6.2.4.)
  • the Atom
    Atom (standard)
    The name Atom applies to a pair of related 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.Web feeds allow software programs to check for updates published on a...

     <link> element with rel="enclosure"

See also

  • Broadcatching
    Broadcatching
    Broadcatching is the downloading of digital content that has been made available over the Internet using RSS.The general idea is to use an automated mechanism to aggregate various web feeds and download content for viewing or presentation purposes....

  • Internet television
    Internet television
    Internet television is the digital distribution of television content via the Internet...

  • Podcast
    Podcast
    A podcast is a series of digital media files that are released episodically and often downloaded through web syndication...

  • Photofeed
    Photofeed
    A photofeed is a web feed that features image enclosures. They provide an easy, standard way to reference a list of images with title, date and description....

  • Vlog
    Vlog
    Video blogging, sometimes shortened to vlogging or vidding or vidblogging is a form of blogging for which the medium is video, and is a form of Web television. Entries often combine embedded video or a video link with supporting text, images, and other metadata. Entries can be recorded in one take...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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