hcalendar-ja

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hCalendar

microformat_hcalendar.png

hCalendarはiCalendar (RFC2445)を基とした、シンプルでオープンなカレンダー・イベント情報配信用のmicroformatです。(X)HTMLやAtom, RSS, 任意のXMLなど、広範囲に適用可能なフォーマットとなっています。

hCalendarでイベント情報を配信するにはいくつかの方法があります。手っ取り早いのは、hCalendar creatorを使うこと。でももし、すでにイベントの情報を自分のblogやwikiなどに書いている場合はhCalendar authoring tipsを読み、hCalendarに沿うようマークアップをし直しましょう。

仕様

編者
Tantek Çelik (Technorati, Inc)
作者
Tantek Çelik, Technorati, Inc
Brian Suda

著作権

© 2004-2024 by the authors.

この仕様の著作権は、ページ編集に関わった人全てが保有しています。 しかし、著者はこの仕様をGMPGやIETF、W3Cなどの標準化団体に提出することを考えています。この仕様に貢献したい場合は、これらの団体が持つ著作権に対する方針やポリシー（例:GMPG Principles）を読み、ライセンスに関する規定（例:CC-by 1.0や後のバージョン）を理解した上でお願いします。

特許方針

この仕様はロイヤリティーフリーの特許方針に帰属するものです。特許方針に関してはW3C Patent PolicyやRFC3667、RFC3668をご覧下さい。

謝辞

Thanks to:

概要

iCalendar (RFC2445)はAppleのiCalなど、スケジュール管理用アプリケーションに広く採用され、また実装上の相互運用性も高いフォーマットになっています。

この広く使われているフォーマットを、blogで言及されるイベント情報に応用できないでしょうか。自分のblogにこれから行われるイベントであったり、この間参加したイベントについてエントリをおこすブロガーはたくさんいます。それらのイベント情報を少し構造化し、iCalendarとして出力可能にすれば、アプリケーションやWebサービスが自動的にその情報を利用できるようになります。

このhCalendarというう仕様は、XHTMLにてiCalendarを表現するフォーマットです。ブロガーはhCalendarを直接webページに埋め込んだり、またその情報をCSSでデザインすることが可能です。それだけではありません。アプリケーションはイベント情報を直接そのhCalendarから取ってくることができるようにります。イベントについて書かれたファイルを、webページとは別に用意する必要はもうありません。

Semantic XHTML Design Principles

Note: the Semantic XHTML Design Principles were written primarily within the context of developing hCard and hCalendar, thus it may be easier to understand these principles in the context of the hCard design methodology (i.e. read that first). Tantek

XHTML is built on XML, and thus XHTML based formats can be used not only for convenient display presentation, but also for general purpose data exchange. In many ways, XHTML based formats exemplify the best of both HTML and XML worlds. However, when building XHTML based formats, it helps to have a guiding set of principles.

  1. Reuse the schema (names, objects, properties, values, types, hierarchies, constraints) as much as possible from pre-existing, established, well-supported standards by reference. Avoid restating constraints expressed in the source standard. Informative mentions are ok.
    1. For types with multiple components, use nested elements with class names equivalent to the names of the components.
    2. Plural components are made singular, and thus multiple nested elements are used to represent multiple text values that are comma-delimited.
  2. Use the most accurately precise semantic XHTML building block for each object etc.
  3. Otherwise use a generic structural element (e.g. <span> or <div>), or the appropriate contextual element (e.g. an <li> inside a <ul> or <ol>).
  4. Use class names based on names from the original schema, unless the semantic XHTML building block precisely represents that part of the original schema. If names in the source schema are case-insensitive, then use an all lowercase equivalent. Components names implicit in prose (rather than explicit in the defined schema) should also use lowercase equivalents for ease of use. Spaces in component names become dash '-' characters.
  5. Finally, if the format of the data according to the original schema is too long and/or not human-friendly, use <abbr> instead of a generic structural element, and place the literal data into the 'title' attribute (where abbr expansions go), and the more brief and human readable equivalent into the element itself. Further informative explanation of this use of <abbr>: Human vs. ISO8601 dates problem solved

For practical implementations, it should be noted that Internet Explorer's support for styling <abbr> elements is poor, and may require wrapper elements.

Format

In General

The iCalendar standard (RFC2445) forms the basis of hCalendar.

Note: the editor and authors of this specification are tracking the "iCal-Basic" effort and intend to base the core hCalendar profile on iCal-Basic. See references for a link to the current draft.

The basic format of hCalendar is to use iCalendar object/property names in lower-case for class names, and to map the nesting of iCalendar objects directly into nested XHTML.

More Semantic Equivalents

However, for some properties there is a more semantic equivalent, and therefore they get special treatment, e.g.:

  • URL in iCalendar becomes <a class="url" href="...">...</a> inside the element with class="vevent" in hCalendar.
  • ATTENDEE, CONTACT, and ORGANIZER in iCalendar may be represented by an hCard in hCalendar .
  • A named LOCATION (potentially with an address and/or geo) in iCalendar may be represented by a nested hCard in hCalendar. Similarly, an address LOCATION may be represented by an adr, and a geo (latitude and longitude) LOCATION may be represented by a geo.
  • UID in iCalendar simply becomes another semantic applied to a specific URL for an hCalendar event.

Singular vs. Plural Properties

For properties which are singular (e.g. "N" and "FN" from vCard), the first descendant element with that class should take effect, any others being ignored.

For properties which can be plural (e.g. "TEL" from vCard), each class instance should create a instance of that property. Plural properties with subtypes (e.g. TEL with WORK, HOME, CELL from vCard) can be optimized to share a common element for the property itself, with each instance of subtype being an appropriately classed descendant of the property element.

Plural Properties Singularized

Since plural property names become their singular equivalents, even if the original plural property permitted only a single value with multiple components, those multiple components are represented each with their own singularly named property and the the property is effectively multivalued and subject to the above treatment of multivalued properties.

Human vs. Machine readable

If an <abbr> element is used for a property, then the 'title' attribute of the <abbr> element is the value of the property, instead of the contents of the element, which instead provide a human presentable version of the value. This specification recommends that such <abbr> elements be used for the following iCalendar properties:

  • DTSTART, DTEND, DURATION, RDATE, RRULE

Example

Here is a sample event in an iCalendar: 

BEGIN:VCALENDAR
PRODID:-//XYZproduct//EN
VERSION:2.0
BEGIN:VEVENT
URL:http://www.web2con.com/
DTSTART:20071005
DTEND:20071020
SUMMARY:Web 2.0 Conference
LOCATION:Argent Hotel\, San Francisco\, CA
END:VEVENT
END:VCALENDAR

and an equivalent event in hCalendar format with various elements optimized appropriately. See hcalendar-example1-steps for the derivation. 

<div class="vevent">
 <a class="url" href="http://www.web2con.com/">http://www.web2con.com/</a>
  <span class="summary">Web 2.0 Conference</span>: 
  <abbr class="dtstart" title="2007-10-05">October 5</abbr>-
  <abbr class="dtend" title="2007-10-20">19</abbr>,
 at the <span class="location">Argent Hotel, San Francisco, CA</span>
 </div>

which could be displayed as:

http://www.web2con.com/

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