Metadata

Information about channels and feed items is stored as metadata (information about information), arranged in a tree-like hierarchy.

A metadata entry can be one of two types:

metadata value: has an associated value.

metadata group: used to group metadata values together.

For example, a channel's metadata might look something like the diagram to the right. There are two metadata groups, Link and Author, and everything else is a metadata value.

While each type of metadata can be used either as a value or group, in practice each is typically used as one or the other.

The following are usually used as metadata groups.

Author

Feed/item author.

This will have one or more of the following child nodes: Name, URL, Email

Contributor

Feed/item contributor.

This will have one or more of the following child nodes: Name, URL, Email

Editor

Channel editor.

This will have either a Name or Email child node.

Webmaster

Channel webmaster.

This will have either a Name or Email child node.

Image

Channel image.

This will have a URL child node and optionally Width and/or Height child nodes.

Icon

Channel icon.

This will have a URL child node.

Category

Feed/item category.

This will have one or more of the following child nodes: ID, URL, Name

Link

A link.

This will have a URL child node and any of the following optional child nodes: Relation, Name, MediaType, Language.

Comments

Indicates where a feed item's comments can be found.

This metadata node is found in RSS feeds only and has a single URL child node.

Source

States the item's source.

For RSS feeds, this will have a Link and/or a Name child node. For Atom 1.0 feeds, it will have one or more of the following child nodes: ID, Name, Description, Author, Contributor, Link, Category, Copyright, Icon, Image, Modified.

The following are usually used as metadata values.

Feed/item identifier.

Name

Feed/item name.

Description

Feed/item description.

Feed/item copyright message.

Language

Feed/item language ID.

Published

Feed/item published date.

Modified

Feed/item modified date.

URL

Specifies a URL.

Specifies an email address.

SkipDays

Specifies which days a feed should not be updated.

This metadata is found in RSS feeds only and is a list of day numbers (where 0=Sunday).

SkipHours

Specifies which hours a feed should not be updated.

This metadata is found in RSS feeds only and is a list of hour numbers (0-23).

Relation

Specifies a relation type.

This is usually a child of a Link node and specifies the link's reltype.

MediaType

Specifies a media type.

This is usually a child of a Link node and specifies the link's media type.

Width

Specifies a width.

Height

Specifies a height.

Size

Specifies a size.

Length

Specifies a length.

Metadata ID	Description
Author	Feed/item author. This will have one or more of the following child nodes: Name, URL, Email
Contributor	Feed/item contributor. This will have one or more of the following child nodes: Name, URL, Email
Editor	Channel editor. This will have either a Name or Email child node.
Webmaster	Channel webmaster. This will have either a Name or Email child node.
Image	Channel image. This will have a URL child node and optionally Width and/or Height child nodes.
Icon	Channel icon. This will have a URL child node.
Category	Feed/item category. This will have one or more of the following child nodes: ID, URL, Name
Link	A link. This will have a URL child node and any of the following optional child nodes: Relation, Name, MediaType, Language.
Comments	Indicates where a feed item's comments can be found. This metadata node is found in RSS feeds only and has a single URL child node.
Source	States the item's source. For RSS feeds, this will have a Link and/or a Name child node. For Atom 1.0 feeds, it will have one or more of the following child nodes: ID, Name, Description, Author, Contributor, Link, Category, Copyright, Icon, Image, Modified.