hatom-hints

hAtom Hints

hAtom is a microformat for content that can be syndicated, primarily but not exclusively weblog postings. This page gives hints on how to use, implement and embed hAtom, backgrounders and other information closely related to the hAtom spec but that doesn't strictly belong on the main page.

If there's a conflict between this page and the spec, the spec is correct.

This page is currently out-of-date. Consult the accordant microformat specification for up-to-date information.

Schema Notes

Nomenclature

Note: Please see the hatom-issues document for discussion on property names.

Concept	Atom Identifier	hAtom Microformat Usage
Feed	atom:feed	Add class name "hfeed"
Entry	atom:entry	Add class name hentry; if practical, also define id="unique-identifier" to the Entry.
Entry Title	atom:title	Add class name headline. Using <h#> also is encouraged.
Entry Content	atom:content	Add class name content to all appropriate blocks. Multiple Entry Content blocks are logically considered one concatenated atom:content equivalent.
Entry Summary	atom:summary	Add class name excerpt to all appropriate blocks. Multiple Entry Summary blocks are logically considered one concatenated atom:summary equivalent.
Entry Permalink	atom:link	Add a rel value of bookmark.
Entry Published	atom:published	Use class name published, optionally with the datetime-design-pattern.
Entry Updated	atom:updated	Use class nameupdated, with an ISO8601 absolute datetime, optionally with the datetime-design-pattern.
Entry Author	atom:author	Add class name "author. Using an address element is recommended. A hCard SHOULD be added.

Nesting Rules

Concept	Nests In	hAtom Opaque	Cardinality	Logical Cardinality Informative
Feed	HTML document	No	1-N	1-N
Entry	Feed	No	0-N	0-N
Entry Title	Entry Entry Permalink	No	0-N	0-1
Entry Content	Entry	Yes	0-N	0-1
Entry Summary	Entry	Yes	0-N	0-1
Entry Permalink	Entry Entry Title Entry Published	No	0-N	1
Entry Published	Entry Entry Permalink	No	0-N	0-1
Entry Updated	Entry Entry Permalink	No	0-N	1
Entry Author	Entry	Yes	0-N	1-N

hAtom Opaque

"hAtom Opaque" specifies whether a hAtom parser should not "look inside" the element for further hAtom content. If there are multiple rules applied to the same element take the OR of the two (i.e. "Yes/Opaque" always wins)

hAtom Opaque is designed to make parsing rules less ambiguous. In particular, it allows "quoted" hAtom elements (from another blog being blockquoted, for example) ti be ignored. It also allows 'embedded' hAtom to be potentially delivered within hAtom itself, and to prevent accidental 'leaking' of other microformat information up into the hAtom container. A general concept of opaqueness (need link) has also been proposed but it will complement, not replace this.

Cardinality

How many times can an element of the given type appear in it's nesting/parent element.

Logical Cardinality

This column is informative -- Atom has a number of rules for deciding what is required depending on the context and other elements, many which aren't strictly applicable to here.

From a modeling/logical perspective, the number of times can an element appear.

This is all rule dependent, see below. For example, an Entry Permalink may appear 6 times, but each one must be the same value; an Entry Content element may appear 3 times, but they are all concatenated together to make a single logical element.

Element notes

Feed

• you could have multiple feeds on news pages, or weblogs with "mini-blogs" on the sidebar.
• class="hfeed hentry" is OK for feeds with a single entry.

Entry Permalink

• Entry Permalinks SHOULD be the same as the atom:link (or rss:link) used in syndication feeds

The intention of the previous two rules to gently force people to use strings that can be byte compared for equivalence. In general, the canonical URI should be the link used in an Atom entry.

• if an Entry has multiple elements marked as the Entry Permalink, they MUST have exactly the same URI

See Also

• h-entry - latest markup spec for Atom entries in HTML
• h-feed - brainstorm/experiment for feeds in HTML
• hAtom - the draft proposal.
• hAtom Cheatsheet - hAtom properties.
• hAtom Examples, in the Wild
• hAtom Hints - help for implementors.
• hAtom Issues - problems? complaints? ideas? Put them here.
• hatom-brainstorming - active work on iterations toward the next version of hAtom
• hAtom FAQ - knowledge base.
• hAtom advocacy - encourage others to use hAtom.