feed URI scheme
In computing, the feed: URI scheme (sometimes referred to, somewhat imprecisely, as the feed protocol; see Protocol (computing)) is a non-standard URI scheme designed to facilitate subscription to web feeds; specifically, it is intended that a news aggregator be launched whenever a hyperlink to a feed: URI is clicked in a web browser.
The scheme is used to flag a document in a syndication format such as Atom or RSS. The document is served over HTTP.
Critics hold that the purpose of the feed: URI scheme is better served by MIME types,[1] or that it is not a user-friendly solution for the problem of feed subscription, since a user who has not installed the appropriate software will receive an unhelpful browser error message on clicking a link to a feed: URI.
The feed: URI scheme is currently supported by several popular desktop aggregators, including NetNewsWire, FeedDemon, Safari, and Flock, although as of 2006 no effort seems to be underway to officially register the scheme with a standards body.[citation needed]
Syntax
The syntax for a feed: URI may be expressed in Backus–Naur form as follows:
<feed_uri> ::= "feed:" <absolute_uri> | "feed://" <hier_part>
Specifically, a feed: URI may be formed from any absolute URI (such as an absolute URL) by prepending feed:, and as a special case, may be formed from any absolute http: URI by replacing the initial http:// with feed://. Therefore, the following are two examples of valid feed: URIs:
feed://example.com/rss.xml feed:https://example.com/rss.xml
There is also a proposed extension of the syntax that supports metadata and embedded instructions to the aggregator.[2]
External links
- The feed URI scheme — pre-draft version of a specification from 2004
- The feed protocol format — including proposal for extensions