Microdata vocabularies: vEvent

Abstract

This specification defines a microdata vocabulary (an item type and associated defined property names) for events, based on the vEvent part of the iCalendar format.

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The W3C HTML Working Group is the W3C working group responsible for this specification's progress along the W3C Recommendation track. This specification is the 27 October 2009 Editor's Draft.

The text of this specification is also available as part of the WHATWG's Microdata Vocabularies specification, in its vEvent section. This normative content of this specification and the vEvent section of the WHATWG specification are identical.

This specification is intended to define vocabularies for HTML5's Microdata feature to address the most important use cases for which Microdata was created. It is specified independently to allow the Microdata vocabularies to evolve independently of the HTML5 specification itself.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

Table of contents

1. 1 The vocabulary
2. 2 Conversion to iCalendar
3. 3 Examples
4. References

1 The vocabulary

This section defines a microdata vocabulary. [HTML5]

An item with the item type http://microformats.org/profile/hcalendar#vevent represents an event.

This vocabulary supports global identifiers for items.

The following are the type's defined property names. They are based on the vocabulary defined in the iCalendar specification, where more information on how to interpret the values can be found. [RFC2445]

Only the parts of the iCalendar vocabulary relating to events are used here; this vocabulary cannot express a complete iCalendar instance.

attach

Gives the address of an associated document for the event.

The value must be an absolute URL.

Any number of properties with the name attach may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

categories

Gives the name of a category or tag that the event could be classified as.

The value must be text.

Any number of properties with the name categories may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

class

Gives the access classification of the information regarding the event.

The value must be text with one of the following values:

• public
• private
• confidential

This is merely advisory and cannot be considered a confidentiality measure.

A single property with the name class may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

comment

Gives a comment regarding the event.

The value must be text.

Any number of properties with the name comment may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

description

Gives a detailed description of the event.

The value must be text.

A single property with the name description may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

geo

Gives the geographical position of the event.

The value must be text and must match the following syntax:

1. Optionally, either a U+002B PLUS SIGN character (+) or a U+002D HYPHEN-MINUS character (-).
2. One or more digits in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9).
3. Optionally*, a U+002E FULL STOP character (.) followed by one or more digits in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9).
4. A U+003B SEMICOLON character (;).
5. Optionally, either a U+002B PLUS SIGN character (+) or a U+002D HYPHEN-MINUS character (-).
6. One or more digits in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9).
7. Optionally*, a U+002E FULL STOP character (.) followed by one or more digits in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9).

The optional components marked with an asterisk (*) should be included, and should have six digits each.

The value specifies latitude and longitude, in that order (i.e., "LAT LON" ordering), in decimal degrees. The longitude represents the location east and west of the prime meridian as a positive or negative real number, respectively. The latitude represents the location north and south of the equator as a positive or negative real number, respectively.

A single property with the name geo may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

location

Gives the location of the event.

The value must be text.

A single property with the name location may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

resources

Gives a resource that will be needed for the event.

The value must be text.

Any number of properties with the name resources may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

status

Gives the confirmation status of the event.

The value must be text with one of the following values:

• tentative
• confirmed
• cancelled

A single property with the name status may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

summary

Gives a short summary of the event.

The value must be text.

User agents should replace U+000A LINE FEED (LF) characters in the value by U+0020 SPACE characters when using the value.

A single property with the name summary may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

dtend

Gives the date and time by which the event ends.

If the property with the name dtend is present within an item with the type http://microformats.org/profile/hcalendar#vevent that has a property with the name dtstart whose value is a valid date string, then the value of the property with the name dtend must be text that is a valid date string also. Otherwise, the value of the property must be text that is a valid global date and time string.

In either case, the value be later in time than the value of the dtstart property of the same item.

The time given by the dtend property is not inclusive. For day-long events, therefore, the the dtend property's value will be the day after the end of the event.

A single property with the name dtend may be present within each item with the type http://microformats.org/profile/hcalendar#vevent, so long as that http://microformats.org/profile/hcalendar#vevent does not have a property with the name duration.

dtstart

Gives the date and time at which the event starts.

The value must be text that is either a valid date string or a valid global date and time string.

Exactly one property with the name dtstart must be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

duration

Gives the date and time at which the event starts.

The value must be text that is a valid vevent duration string.

The duration represented is the sum of all the durations represented by integers in the value.

A single property with the name duration may be present within each item with the type http://microformats.org/profile/hcalendar#vevent, so long as that http://microformats.org/profile/hcalendar#vevent does not have a property with the name dtend.

transp

Gives whether the event is to be considered as consuming time on a calendar, for the purpose of free-busy time searches.

The value must be text with one of the following values:

• opaque
• transparent

A single property with the name transp may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

contact

Gives the contact information for the event.

The value must be text.

Any number of properties with the name contact may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

url

Gives a URL for the event.

The value must be an absolute URL.

A single property with the name url may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

exdate

Gives a date and time at which the event does not occur despite the recurrence rules.

The value must be text that is either a valid date string or a valid global date and time string.

Any number of properties with the name exdate may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

exrule

Gives a rule for finding dates and times at which the event does not occur despite the recurrence rules.

The value must be text that matches the RECUR value type defined in the iCalendar specification. [RFC2445]

Any number of properties with the name exrule may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

rdate

Gives a date and time at which the event recurs.

The value must be text that is one of the following:

• A valid date string.
• A valid global date and time string.
• A valid global date and time string followed by a U+002F SOLIDUS character (/) followed by a second valid global date and time string representing a later time.
• A valid global date and time string followed by a U+002F SOLIDUS character (/) followed by a valid vevent duration string.

Any number of properties with the name rdate may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

rrule

Gives a rule for finding dates and times at which the event occurs.

The value must be text that matches the RECUR value type defined in the iCalendar specification. [RFC2445]

Any number of properties with the name rrule may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

created

Gives the date and time at which the event information was first created in a calendaring system.

The value must be text that is a valid global date and time string.

A single property with the name created may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

last-modified

Gives the date and time at which the event information was last modified in a calendaring system.

The value must be text that is a valid global date and time string.

A single property with the name last-modified may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

sequence

Gives a revision number for the event information.

The value must be text that is a valid non-negative integer.

A single property with the name sequence may be present within each item with the type http://microformats.org/profile/hcalendar#vevent.

A string is a valid vevent duration string if it matches the following pattern:

1. A U+0050 LATIN CAPITAL LETTER P character (P).
2. One of the following:
   • A valid non-negative integer followed by a U+0057 LATIN CAPITAL LETTER W character (W). The integer represents a duration of that number of weeks.
   • At least one, and possible both in this order, of the following:
     1. A valid non-negative integer followed by a U+0044 LATIN CAPITAL LETTER D character (D). The integer represents a duration of that number of days.
     2. A U+0054 LATIN CAPITAL LETTER T character (T) followed by any one of the following, or the first and second of the following in that order, or the second and third of the following in that order, or all three of the following in this order:
        1. A valid non-negative integer followed by a U+0048 LATIN CAPITAL LETTER H character (H). The integer represents a duration of that number of hours.
        2. A valid non-negative integer followed by a U+004D LATIN CAPITAL LETTER M character (M). The integer represents a duration of that number of minutes.
        3. A valid non-negative integer followed by a U+0053 LATIN CAPITAL LETTER S character (S). The integer represents a duration of that number of seconds.

2 Conversion to iCalendar

Given a list of nodes nodes in a Document, a user agent must run the following algorithm to extract any vEvent data represented by those nodes:

1. If none of the nodes in nodes are items with the type http://microformats.org/profile/hcalendar#vevent, then there is no vEvent data. Abort the algorithm, returning nothing.

2. Let output be an empty string.

3. Add an iCalendar line with the type "BEGIN" and the value "VCALENDAR" to output.

4. Add an iCalendar line with the type "PRODID" and the value equal to a user-agent-specific string representing the user agent to output.

5. Add an iCalendar line with the type "VERSION" and the value "2.0" to output.

6. For each node node in nodes that is an item with the type http://microformats.org/profile/hcalendar#vevent, run the following steps:

   1. Add an iCalendar line with the type "BEGIN" and the value "VEVENT" to output.

   2. Add an iCalendar line with the type "DTSTAMP" and a value consisting of an iCalendar DATE-TIME string representing the current date and time, with the annotation "VALUE=DATE-TIME", to output. [RFC2445]

   3. If the item has a global identifier, add an iCalendar line with the type "UID" and that global identifier as the value to output.

   4. For each element element that is a property of the item node: for each name name in element's property names, run the appropriate set of substeps from the following list:

      If the property's value is an item

      Skip the property.

      If element is a time element

      Let value be the result of stripping all U+002D HYPHEN-MINUS (-) and U+003A COLON (:) characters from the property's value.

      If the property's value is a valid date string then add an iCalendar line with the type name and the value value to output, with the annotation "VALUE=DATE".

      Otherwise, if the property's value is a valid global date and time string then add an iCalendar line with the type name and the value value to output, with the annotation "VALUE=DATE-TIME".

      Otherwise skip the property.

      Otherwise

      Add an iCalendar line with the type name and the value value to output.

   5. Add an iCalendar line with the type "END" and the value "VEVENT" to output.

7. Add an iCalendar line with the type "END" and the value "VCALENDAR" to output.

When the above algorithm says that the user agent is to add an iCalendar line consisting of a type type, a value value, and optionally an annotation, to a string output, it must run the following steps:

1. Let line be an empty string.

2. Append type, converted to ASCII uppercase, to line.

3. If there is an annotation:

   1. Append a U+003B SEMICOLON character (;) to line.

   2. Append the annotation to line.

4. Append a U+003A COLON character (:) to line.

5. Prefix every U+005C REVERSE SOLIDUS character (\) in value with another U+005C REVERSE SOLIDUS character (\).

6. Prefix every U+002C COMMA character (,) in value with a U+005C REVERSE SOLIDUS character (\).

7. Prefix every U+003B SEMICOLON character (;) in value with a U+005C REVERSE SOLIDUS character (\).

8. Replace every U+000D CARRIAGE RETURN U+000A LINE FEED character pair (CRLF) in value with a U+005C REVERSE SOLIDUS character (\) followed by a U+006E LATIN SMALL LETTER N character (n).

9. Replace every remaining U+000D CARRIAGE RETURN (CR) or U+000A LINE FEED (LF) character in value with a U+005C REVERSE SOLIDUS character (\) followed by a U+006E LATIN SMALL LETTER N character (n).

10. Append value to line.

11. Let maximum length be 75.

12. If and while line is longer than maximum length Unicode code points long, run the following substeps:

    1. Append the first maximum length Unicode code points of line to output.

    2. Remove the first maximum length Unicode code points from line.

    3. Append a U+000D CARRIAGE RETURN character (CR) to output.

    4. Append a U+000A LINE FEED character (LF) to output.

    5. Append a U+0020 SPACE character to output.

    6. Let maximum length be 74.

13. Append (what remains of) line to output.

14. Append a U+000D CARRIAGE RETURN character (CR) to output.

15. Append a U+000A LINE FEED character (LF) to output.

This algorithm can generate invalid iCalendar output, if the input does not conform to the rules described for the http://microformats.org/profile/hcalendar#vevent item type and defined property names.

3 Examples

<body itemscope itemtype="http://microformats.org/profile/hcalendar#vevent">
 ...
 <h1 itemprop="summary">Bluesday Tuesday: Money Road</h1>
 ...
 <time itemprop="dtstart" datetime="2009-05-05T19:00:00Z">May 5th @ 7pm</time>
 (until <time itemprop="dtend" datetime="2009-05-05T21:00:00Z">9pm</time>)
 ...
 <a href="http://livebrum.co.uk/2009/05/05/bluesday-tuesday-money-road"
    rel="bookmark" itemprop="url">Link to this page</a>
 ...
 <p>Location: <span itemprop="location">The RoadHouse</span></p>
 ...
 <p><input type=button value="Add to Calendar"
           onclick="location = getCalendar(this)"></p>
 ...
 <meta itemprop="description" content="via livebrum.co.uk">
</body>

function getCalendar(node) {
  while (node && (!node.nodeScope || !node.itemType == 'http://microformats.org/profile/hcalendar#vevent'))
    node = node.parentNode;
  if (!node) {
    alert('No event data found.');
    return;
  }
  var stamp = new Date();
  var stampString = '' + stamp.getUTCFullYear() + (stamp.getUTCMonth() + 1) + stamp.getUTCDate() + 'T' +
                         stamp.getUTCHours() + stamp.getUTCMinutes() + stamp.getUTCSeconds() + 'Z';
  var calendar = 'BEGIN:VCALENDAR\r\nPRODID:HTML\r\nVERSION:2.0\r\nBEGIN:VEVENT\r\nDTSTAMP:' + stampString + '\r\n';
  if (node.itemId)
    calendar += 'UID:' + node.itemId + '\r\n';
  for (var propIndex = 0; propIndex < node.properties.length; propIndex += 1) {
    var prop = node.properties[propIndex];
    var value = prop.itemValue;
    var parameters = '';
    if (prop.localName == 'time') {
      value = value.replace(/[:-]/g, '');
      if (prop.date && prop.time)
        parameters = ';VALUE=DATE';
      else
        parameters = ';VALUE=DATE-TIME';
    } else {
      value = value.replace(/\\/g, '\\n');
      value = value.replace(/;/g, '\\;');
      value = value.replace(/,/g, \\,');
      value = value.replace(/\n/g, '\\n');
    }
    for (var nameIndex = 0; nameIndex < prop.itemProp.length; nameIndex += 1) {
      var name = prop.itemProp[nameIndex];
      if (!name.match(':') && !name.match('.'))
        calendar += name.toUpperCase() + parameters + ':' + value + '\r\n';
    }
  }
  calendar += 'END:VEVENT\r\nEND:VCALENDAR\r\n';
  return 'data:text/calendar;component=vevent,' + encodeURI(calendar);
}

<div itemscope itemtype="http://microformats.org/profile/hcalendar#vevent">
 <p>I'm going to
 <strong itemprop="summary">Bluesday Tuesday: Money Road</strong>,
 <time itemprop="dtstart" datetime="2009-05-05T19:00:00Z">May 5th at 7pm</time>
 to <time itemprop="dtend" content="2009-05-05T21:00:00Z">9pm</time>,
 at <span itemprop="location">The RoadHouse</span>!</p>
 <p><a href="http://livebrum.co.uk/2009/05/05/bluesday-tuesday-money-road"
       itemprop="url">See this event on livebrum.co.uk</a>.</p>
 <meta itemprop="description" content="via livebrum.co.uk">
</div>

References

[HTML5]

HTML5, I. Hickson. WHATWG, August 2009.

[RFC2445]

Internet Calendaring and Scheduling Core Object Specification (iCalendar), F. Dawson, D. Stenerson. IETF, November 1998.