Atom Activity Base Schema (Draft)
activity-schema-01

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Abstract

This document presents a base set of Object types and Verbs for use with Atom Activity Extensions.

Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 (, “RFC 2119,” .) [RFC2119].

Table of Contents

1.  Introduction
2.  Notational Conventions
3.  Base Schema
    3.1.  Base Verbs
        3.1.1.  Mark as Favorite
        3.1.2.  Start Following
        3.1.3.  Mark as Liked
        3.1.4.  Make Friend
        3.1.5.  Join
        3.1.6.  Play
        3.1.7.  Post
        3.1.8.  Save
        3.1.9.  Share
        3.1.10.  Tag
        3.1.11.  Update
    3.2.  Base Object Types
        3.2.1.  Article
        3.2.2.  Audio
        3.2.3.  Bookmark
        3.2.4.  Comment
        3.2.5.  File
        3.2.6.  Folder
        3.2.7.  Group
        3.2.8.  List
        3.2.9.  Note
        3.2.10.  Person
        3.2.11.  Photo
        3.2.12.  Photo Album
        3.2.13.  Place
        3.2.14.  Playlist
        3.2.15.  Product
        3.2.16.  Review
        3.2.17.  Service
        3.2.18.  Status
        3.2.19.  Video
    3.3.  Base Activity Context Elements
        3.3.1.  Location
        3.3.2.  Mood
    3.4.  Replies
4.  Event Schema
    4.1.  Event Verbs
        4.1.1.  Positive RSVP
        4.1.2.  Possible RSVP
        4.1.3.  Negative RSVP
    4.2.  Event Object Types
        4.2.1.  Event
5.  Music Schema
    5.1.  Music Object Types
        5.1.1.  Song
6.  Normative References
Appendix A.  Acknowledgements
§  Authors' Addresses

1.  Introduction

This document presents a base set of Object types and Verbs for use with Atom Activity Extensions.

2.  Notational Conventions

In this document, the following namespace prefixes are used for the given namespace URI from the referenced specification:

The choices of namespace prefix are arbitrary and not semantically significant.

This specification uses a shorthand form of terms from the XML Infoset [W3C.REC-xml-infoset-20040204]. The phrase "Information Item" is omitted when naming Element and Attribute Information Items. Therefore, when this specification uses the term "element," it is referring to an Element Information Item in Infoset terms. Likewise, when this specification uses the term "attribute," it is referring to an Attribute Information Item.

This specification allows the use of IRIs [RFC3987]. Every URI [RFC3986] is also an IRI, so a URI MAY be used wherever an IRI is named. When an IRI that is not also a URI is given for dereferencing, it MUST be mapped to a URI using the steps in Section 3.1 of [RFC3987]. When an IRI is serving as an identifier, it MUST NOT be so mapped.

Some sections of this specification are illustrated with a non- normative RELAX NG Compact schema [RELAXNG]. In those sections, this specification uses the atomCommonAttributes, atomMediaType, and atomURI patterns, defined in [RFC4287].

However, the text of this specification provides the sole definition of conformance.

This specification uses "the Atom specification" to refer to [RFC4287] (, “The Atom Syndication Format,” .), and "the AtomActivity specification" to refer to [insert xref here].

3.  Base Schema

The base schema provides generic terms that all activity consumers SHOULD support. The other, more specific sections that follow use specializations of this base vocabulary to provide additional terms that may only be useful in certain applications.

3.1.  Base Verbs

3.1.1.  Mark as Favorite

The "mark as favorite" Verb indicates that the Subject marked the Object as an item of special interest. Objects so marked often appear in a collection of such Objects which MAY be published as a feed of entries annotated with this Verb.

If a particular service uses favorites as a mechanism by which a user can recall items that were earlier marked, it MAY be appropriate to also mark activities of this type with the "save" Verb as described in Section 3.1.8 (Save).

The verb URI for the "mark as favorite" Verb is http://activitystrea.ms/schema/1.0/favorite.

3.1.2.  Start Following

The "start following" Verb indicates that the Subject began following the activity of the Object. In most cases, the Object of this Verb will be a user, but it can potentially be of any type that can sensibly generate activity.

The verb URI for the "start following" Verb is http://activitystrea.ms/schema/1.0/follow.

Processors MAY ignore (silently drop) successive identical "start following" activities regardless of whether they maintain state sufficient to determine (A), (B), or (C) above.

3.1.3.  Mark as Liked

The "mark as liked" verb indicates that the actor indicated that it likes the object.

The verb URI for the "mark as liked" Verb is http://activitystrea.ms/schema/1.0/like.

3.1.4.  Make Friend

The "make friend" Verb indicates the creation of a friendship that is reciprocated by the object.

Since this verb implies an activity on the part of its object, processors MUST NOT accept activities with this Verb unless they are able to verify through some external means that there is in fact a reciprocated connection. For example, a processor MAY have received a guarantee from a particular publisher that the publisher will only use this Verb in cases where a reciprocal relationship exists.

The verb URI for the "make friend" Verb is http://activitystrea.ms/schema/1.0/make-friend.

3.1.5.  Join

The "join" Verb indicates that the actor has become a member of the Object. This specification only defines the meaning of this Verb when its Object is a group, though implementors SHOULD be prepared to handle other Object types as meaning MAY be provided by extension specifications.

Processors MAY ignore (silently drop) successive identical "join" activities regardless of whether they maintain state sufficient to determine (A) or (B) above.

The verb URI for the "join" Verb is http://activitystrea.ms/schema/1.0/join.

3.1.6.  Play

The "play" verb indicates that the subject spent some time enjoying the object. For example, if the object is a video this indicates that the subject watched all or part of the video.

The verb URI for the "play" Verb is http://activitystrea.ms/schema/1.0/play.

3.1.7.  Post

The "Post" Verb is described in section 8 of the AtomActivity specification. It is only referenced here for completeness.

3.1.8.  Save

The "save" Verb indicates that the Subject has called out the Object as being of interest primarily to him- or herself. Though this action MAY be shared publicly, the implication is that the Object has been saved primarily for the actor's own benefit rather than to show it to others as would be indicated by the "share" Verb (Section 3.1.9 (Share)).

The verb URI for the "save" Verb is http://activitystrea.ms/schema/1.0/save.

3.1.9.  Share

The "share" Verb indicates that the Subject has called out the Object to readers. In most cases, the actor did not create the Object being shared, but is instead drawing attention to it.

The verb URI for the "share" Verb is http://activitystrea.ms/schema/1.0/share.

3.1.10.  Tag

The "tag" verb indicates that the actor has identified the presence of a target inside another object. For example, the actor may have specified that a particular user appears in a photo.

The verb URI for the "tag" verb is http://activitystrea.ms/schema/1.0/tag.

The target of the "tag" verb gives the object in which the tag has been added. For example, if a user appears in a photo, the activity:object is the user and the activity:target is the photo.

3.1.11.  Update

The "update" Verb indicates that the Subject has modified the referenced Object.

Implementors SHOULD use verbs such as Section 3.1.7 (Post) where the Subject is adding new items to a Section 3.2.8 (List) or similar. Update is reserved for modifications to existing Objects or data such as changing a user's profile information.

The verb URI for the "update" Verb is http://activitystrea.ms/schema/1.0/update.

3.2.  Base Object Types

3.2.1.  Article

The "article" Object type indicates that the Object is an article, such as a news article, a knowledge base entry, or other similar construct.

Articles generally consist of paragraphs of text, in some cases incorporating embedded media such as photos and inline hyperlinks to other resources.

The Object type URL for the "Article" Object type is http://activitystrea.ms/schema/1.0/article.

An article has the following properties:

title

The title of the entry. Included as the content of the atom:title element. This element MUST be included with empty content if the entry does not have a title.

summary

A short excerpt of the body content that gives an introduction to or a summary of the full content. This element SHOULD be omitted if the entry does not have a summary.

content

The main body content of the entry. Included as the content of the atom:content element.

permalink

The canonical URL for the entry. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

An article is equivalent to a blog entry.

3.2.2.  Audio

The "audio" Object type represents audio content.

The Object type URL for the "audio" Object type is http://activitystrea.ms/schema/1.0/audio.

An audio Object has the following properties:

title

The title or short caption assigned to the audio by the author. Included as the content of the atom:title element. If the author has not provided a title, the publisher MAY synthesize a title e.g. from the audio filename, or the publisher MAY include the atom:title element with no content.

audio stream

The URL and metadata for the audio content itself. The URL is represented as the value of the href attribute on an atom:link element with rel enclosure and a type that matches audio/*. Publishers SHOULD include a media:duration attribute on the atom:link element giving the length of the audio presentation in seconds.

audio page URL

The URL of a web page where the audio and the associated metadata can be accessed. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

player applet

The URL and metadata for some kind of applet that will allow a user to listen to the audio. The URL is represented as the value of the href attribute on an atom:link element with rel alternate and an appropriate type. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the ideal dimensions of the linked applet. If both an audio page and player applet are included, publishers SHOULD include the audio page link element first in document order for compatibility with legacy, non-activity feed consumers.

description

The description or long caption assigned to the audio by the author. Included as the content of the atom:summary element as described in [AtomMedia]. If the author has not provided a description, this element SHOULD be omitted.

3.2.3.  Bookmark

The "bookmark" Object type represents a pointer to some URL -- typically a web page. In most cases, a bookmark is specific to a given user and contains metadata chosen by that user. Bookmark Objects are similar in principle to the concept of bookmarks or favorites in a web browser. A bookmark represents a pointer to the URL, not the URL or the associated resource itself.

When dealing with bookmarks it is important to note the distinction between the title, description, and URL of the bookmark itself and the title, content, and URL of the resource that is the target of the bookmark. In some implementations these MAY be the same, but bookmark managers often allow a user to edit the title and description of his or her own bookmarks to differ from the metadata on the target itself.

Some implementations refer to this Object type as a "link". This specification uses the term "bookmark" to avoid confusion with the general concept of hyperlinks which apply to all Object types.

Since bookmarks are often specific to a particular user, even though multiple users might have bookmarks pointing at the same resource, it is appropriate to use the "post" Verb to describe the publication of such a bookmark. The "mark as favorite" Verb SHOULD be used when a user flags another user's bookmark as being a favorite without creating his own bookmark, or when a user flags his own bookmark as being a favorite as a special classification within his own bookmark collection.

The Object type URL for the "bookmark" Object type is http://activitystrea.ms/schema/1.0/bookmark.

A bookmark has the following properties:

title

The title of the bookmark, as entered by the user who created the bookmark. Included as the content of the atom:title element. Publishers MAY use the title of the target resource as a default for this property where a user hasn't entered a customized value.

description

The description of the bookmark, as entered by the user who created the bookmark. Included as the content of the atom:summary element. If no description has been provided, publishers SHOULD omit this element.

target URL

The URL of the item that is the target of the bookmark. Represented as the value of the href attribute on an atom:link element with rel "related". An entry with this Object type MUST NOT include related links except for the purpose of representing the target URL.

bookmark page URL

The URL of a page that describes the bookmark. This URL is often specific to the user that published the bookmark. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

target title

The title of the item that is the target of the bookmark. Represented as the value of the title attribute on the atom:link element from which the target URL was obtained.

thumbnail

The URL and metadata for a thumbnail version of the page. The URL is represented as the value of the href attribute on an atom:link element with rel preview and a type of either image/jpeg, image/png or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image. Processors MAY ignore thumbnails that are of an inappropriate size for their user interface.

Publishers SHOULD include an atom:content element containing content that will present the bookmark to the user of a processor that does not have special support for bookmarks. Bookmark-aware processors SHOULD prefer the specific properties given above, but MAY use the content in preference in cases where the properties above are incomplete or unsuitable.

3.2.4.  Comment

The "comment" object type represents a textual response to another object.

The comment object type MUST NOT be used for other kinds of replies, such as video replies or reviews.

If an object has no explicit type but the object element has a thr:in-reply-to element a consumer SHOULD consider that object to be a comment.

The object type URL for the "comment" object type is http://activitystrea.ms/schema/1.0/comment.

A comment has the following properties:

subject

The subject of the comment. Included as the content of the atom:title element. Many systems do not have the concept of a title or subject for a comment; such systems MUST include an atom:title element with no text content. Processors SHOULD refer to such comments as simply being "a comment", with appropriate localization, if they are to be described in a sentence.

content

The content of the comment. Included as the content of the atom:content element. Publishers SHOULD include any markup necessary to achieve a similar presentation to that on the publisher's own HTML pages, including any links that the service automatically adds. Processors MAY remove the markup and consider the comment to be plain text.

permalink

The canonical URL for the comment. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html. This URL may be the URL of the parent object with a fragment identifier appended, or a completely distinct URL.

3.2.5.  File

The "file" Object type represents some document or other file with no additional machine-readable semantics.

It is intended that this type be used as a base type for other Objects that manifest as files, so that additional semantics can be added while providing a fallback ability for clients that do not support the more specific Object type.

The Object type URL for the "file" Object type is http://activitystrea.ms/schema/1.0/file.

A file has the following properties:

associated file URL

The URL of the file described by this Object entry. The URL is represented as the value of the href attribute on an atom:link element with rel enclosure. Should there be multiple links with rel enclosure with different type attribute value, they are considered to be alternate representations of the file. Should there be multiple links with rel enclosure and with the same attribute value, the meaning is undefined for the file Object type and consumers MAY choose to present only the first of each supported type.

3.2.6.  Folder

The "folder" object type represents a collection of files or media objects similar to the "photo album" object type, which more specifically represents a collection of "photos."

The object type URL for the "folder" object type is http://activitystrea.ms/schema/1.0/folder.

A folder has the following properties:

title

The title or short caption assigned to the folder by the author. Included as the text of the atom:title element. This element MUST be present for all folder objects. It is acceptable for a folder title attribute to be empty.

folder page URL

The URL of a web page where the folder can be viewed. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html. This element should be present for folder objects

thumbnail

The URL and metadata for a preview image for the folder. The URL is represented as the value of the href attribute on an atom:link element with rel preview and a type of either image/jpeg, image/png or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image. Processors MAY ignore thumbnails that are of an inappropriate size for their user interface. This element may be present for folder objects.

3.2.7.  Group

The "group" Object type represents a social networking group. A group is a collection of people which people can join and leave.

The Object type URL for the "group" Object type is http://activitystrea.ms/schema/1.0/group.

A group has the following properties:

display name

A name that can be used for the group in the user interface. This is often a name chosen by the creator of the group. Included as the content of the atom:title element.

photo

The URL and metadata for an image that represents this group. The URL is represented as the value of the href attribute on an atom:link element with rel photo and a type of either image/jpeg, image/png or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image. Processors MAY ignore photos that are of an inappropriate size for their user interface. Publishers MAY include several images of different sizes.

3.2.8.  List

The list object type represents a collection of related objects.

title

The name of the list. Included as the content of the atom:title element. Systems which produce lists that do not have titles MUST include an atom:title element with no text content.

summary

The description of the list. This description CAN be included.

permaLink

The canonical URL for the list. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

3.2.9.  Note

The "note" Object type represents short-form text messages. This Object type is intended for use in "micro-blogging" and in systems where users are invited to publish short, often plain-text messages whose useful lifespan is generally shorter than that of an article or weblog entry.

A note is similar in structure to an article, but it does not have a title and its body tends to be shorter. Applications will often display the entire content of a note in an activity stream UI, whereas they MAY display only the title or the title and summary for a weblog entry.

The object type URL for the "note" Object type is http://activitystrea.ms/schema/1.0/note.

A note has the following properties:

content

The content of the note. Included as the content of the atom:content element. Publishers SHOULD include any markup necessary to achieve a similar presentation to that on the publisher's own HTML pages, including any links that the service automatically adds. Processors MAY remove the markup and consider the note to be plain text.

permalink

The canonical URL for the note. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

3.2.10.  Person

The "person" Object type represents a user account. This is often a person, but might also be a company or fictitious character that is being represented by a user account.

The object type URL for the "person" Object type is http://activitystrea.ms/schema/1.0/person.

Where a particular person is referred to across multiple sources, the same value for atom:id SHOULD be used wherever possible. Two person objects in the same feed document with the same atom:id value can be considered by processors to be the same person. Processors MAY use other information to determine when two person objects refer to the same individual. A processor MUST NOT assume that two person objects with different values for atom:id refer to different people; different publishers may use different id values for the same individual.

A person has the following properties:

display name

A name that can be used for a person in the user interface. This is often a name by which the individual is known in a given context; no restriction is placed on what kind of name may be used here. Included as the content of the atom:title element.

photo

The URL and metadata for an image that represents this user. The URL is represented as the value of the href attribute on an atom:link element with rel photo and a type of either image/jpeg, image/png, or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image. Processors MAY ignore photos that are of an inappropriate size for their user interface. Publishers MAY include several images of different sizes.

3.2.11.  Photo

The "photo" object type represents a graphical still image.

The object type URL for the "photo" Object type is http://activitystrea.ms/schema/1.0/photo.

A photo has the following properties:

title

The title or short caption assigned to the photo by the author. Included as the content of the atom:title element. If the author has not provided a title, the publisher MAY synthesize a title e.g. from the image filename, or the publisher MAY include the atom:title element with no content.

thumbnail

The URL and metadata for a thumbnail version of the photo. The URL is represented as the value of the href attribute on an atom:link element with rel preview and a type of either image/jpeg, image/png or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image. Processors MAY ignore thumbnails that are of an inappropriate size for their user interface.

larger image

The URL and metadata for a larger, ideally full-size version of the photo intended for standalone viewing. The URL is represented as the value of the href attribute on an atom:link element with rel enclosure and a type of either image/jpeg, image/png or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image.

image page URL

The URL of a web page where the photo and the associated metadata can be viewed. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

description

The description or long caption assigned to the photo by the author. Included as the content of the media:description element as described in [AtomMedia]. If the author has not provided a description, this element SHOULD be omitted.

Publishers SHOULD include an atom:content element containing content that will present the photo and any necessary metadata to the user of a processor that is not media-aware. Media-aware processors SHOULD prefer the specific properties given above, but MAY use the content in preference in cases where the properties above are incomplete or unsuitable.

3.2.12.  Photo Album

The "photo album" object type represents a collection of images.

The object type URL for the "photo album" object type is http://activitystrea.ms/schema/1.0/photo-album.

The photo album object type has the following properties:

title

The title or short caption assigned to the album by the author. Included as the content of the atom:title element.

thumbnail

The URL and metadata for a preview image for the album. The URL is represented as the value of the href attribute on an atom:link element with rel preview and a type of either image/jpeg, image/png or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image. Processors MAY ignore thumbnails that are of an inappropriate size for their user interface.

album page URL

The URL of a web page where the photo album can be viewed. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

3.2.13.  Place

The "place" object type represents a location on Earth.

The object type URL for the "place" object type is http://activitystrea.ms/schema/1.0/place.

A place has the following properties:

name

The name of the place. Included as the content of the atom:title element.

geographic coordinates

The latitude and longitude of the place as a point on Earth. Included via the geo:point element.

3.2.14.  Playlist

The "playlist" object type represents an ordered list of time-based media items, such as video and audio objects.

The object type URL for the "playlist" object type is http://activitystrea.ms/schema/1.0/playlist.

The playlist object type has the following properties:

title

The title or short caption assigned to the playlist by the author. Included as the content of the atom:title element.

thumbnail

The URL and metadata for a preview image for the playlist. The URL is represented as the value of the href attribute on an atom:link element with rel preview and a type of either image/jpeg, image/png or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image. Processors MAY ignore thumbnails that are of an inappropriate size for their user interface.

playlist page URL

The URL of a web page where the playlist can be viewed. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

3.2.15.  Product

The "product" object type represents a commercial good or service.

The object type URL for the "product" object type is http://activitystrea.ms/schema/1.0/product.

A product has the following properties:

title

The title of the product. Included as the content of the atom:title element.

thumbnail

The URL and metadata for a thumbnail photo of the product. The URL is represented as the value of the href attribute on an atom:link element with rel preview and a type of either image/jpeg, image/png or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image. Processors MAY ignore thumbnails that are of an inappropriate size for their user interface.

larger image

The URL and metadata for a larger, ideally full-size version of a photo of the product intended for standalone viewing. The URL is represented as the value of the href attribute on an atom:link element with rel enclosure and a type of either image/jpeg, image/png or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image.

product page URL

The URL of a web page where the photo and the associated metadata can be viewed. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

description

A textural description of the product either from the author or part of the product's metadata may be included in this element. If the full text is included, use the atom:content element. If only a snippet of the content is included, use the atom:summary element.

3.2.16.  Review

The "review" object type represents a primarily prose-based commentary on another object.

The object type URL for the "review" object type is http://activitystrea.ms/schema/1.0/review.

A review has the following properties:

title

The title of the review. Included as the content of the atom:title element. Systems which produce reviews that do not have titles MUST include an atom:title element with no text content. Processors SHOULD refer to such comments as simply being "a review", with appropriate localization, if they are to be described in a sentence.

content

The content of the review. Included as the content of the atom:content element. Publishers SHOULD include any markup necessary to achieve a similar presentation to that on the publisher's own HTML pages, including any links that the service automatically adds.

permalink

The canonical URL for the review. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html. This URL may be the URL of the reviewed object with a fragment identifier appended, or a completely distinct URL.

reviewed object

The object that this review applies to. Included with a thr:in-reply-to element that refers to the atom:id value of the reviewed object.

rating

A rating attribute of the reviewed object. The rating is an optional field and is modeled after the rating attribute from the hReview microformat. Specifically, the rating is defined as a fixed point integer value [1.0-5.0] indicating a rating for the item, higher indicating a better rating by default. Optionally a different integral "worst" value (default:1.0) and/or "best" value (default:5.0) may be specified to indicate a different range (e.g. 6 from 0-10). The "best" value may be numerically smaller than the "worst" value to indicate a descending range.

3.2.17.  Service

The "service" Object type represents a website, personal website or blog, business, brand, or other entity that performs some kind of work for other entities, people, or services, or acts as kind of container for other objects.

The object type URL for the "service" Object type is http://activitystrea.ms/schema/1.0/service.

Where a particular service is referred to across multiple sources, the same value for atom:id SHOULD be used wherever possible. Two service objects in the same feed document with the same atom:id value can be considered by processors to be the same service. Processors MAY use other information to determine when two service objects refer to the same service. A processor MUST NOT assume that two service objects with different values for atom:id refer to different services; different publishers may use different id values for the same service.

A service has the following properties:

display name

A name that can be used for a service in the user interface. This is often a name by which the service is commonly known; no restriction is placed on what kind of name may be used here. Included as the content of the atom:title element.

URI

The URI of the service described by this Object entry. The URI is represented as the value of the href attribute on an atom:link element with rel alternate and type of text/html. Should there be multiple links with rel alternate with different type attribute value, they are considered to be alternate representations of the service. Should there be multiple links with rel alternate and with the same attribute value, the meaning is undefined for the service Object type and consumers MAY choose to present only the first of each supported type.

icon

A small image with an aspect ratio of one (horizontal) to one (vertical) which SHOULD be suitable for presentation at a small size SHOULD be provided to represent the service.

photo

The URL and metadata for an image that represents this service. The URL is represented as the value of the href attribute on an atom:link element with rel photo and a type of either image/jpeg, image/png, or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image. Processors MAY ignore photos that are of an inappropriate size for their user interface. Publishers MAY include several images of different sizes.

3.2.18.  Status

The "status" Object type represents a human-readable update of the author's situation, mood, location or other status.

A status is similar in structure to a note, but carries the additional meaning that the content is primarily describing something its author is doing, feeling or experiencing.

A consumers MAY consider the content of the most recent status object it encountered to be the user's current status, unless the most recent status update is old. When a status becomes too old is not defined by this specification.

The object type URL for the "status" object type is http://activitystrea.ms/schema/1.0/status.

A note has the following properties:

content

The content of the status update. Included as the content of the atom:content element. Publishers SHOULD include any markup necessary to achieve a similar presentation to that on the publisher's own HTML pages, including any links that the service automatically adds. Processors MAY remove the markup and consider the note to be plain text.

permalink

The canonical URL for the status update. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

3.2.19.  Video

The "video" Object type represents video content, which usually consists of a motion picture track and an audio track.

The Object type URL for the "video" Object type is http://activitystrea.ms/schema/1.0/video.

A video has the following properties:

title

The title or short caption assigned to the video by the author. Included as the content of the atom:title element. If the author has not provided a title, the publisher MAY synthesize a title e.g. from the video filename, or the publisher MAY include the atom:title element with no content.

thumbnail

The URL and metadata for a thumbnail version of a representative frame of the video. The URL is represented as the value of the href attribute on an atom:link element with rel preview and a type of either image/jpeg, image/png or image/gif. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked image. Processors MAY ignore thumbnails that are of an inappropriate size for their user interface.

video stream

The URL and metadata for the video content itself. The URL is represented as the value of the href attribute on an atom:link element with rel enclosure and a type that matches video/*. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the dimensions of the linked video, and SHOULD include a media:duration attribute giving the length of the video.

video page URL

The URL of a web page where the video and the associated metadata can be viewed. Represented as the value of the href attribute on an atom:link element with a rel value of alternate and a type value of text/html.

player applet

The URL and metadata for some kind of applet that will allow a user to view the video. The URL is represented as the value of the href attribute on an atom:link element with rel alternate and an appropriate type. Publishers SHOULD include media:width and media:height attributes on the atom:link element describing the ideal dimensions of the linked applet. If both a video page and player applet are included, publishers SHOULD include the video page link element first in document order for compatibility with legacy, non-activity feed consumers.

description

The description or long caption assigned to the video by the author. Included as the content of the atom:summary element as described in [AtomMedia]. If the author has not provided a description, this element SHOULD be omitted.

Publishers SHOULD include an atom:content element containing content that will present the video and any necessary metadata to the user of a processor that is not media-aware. Media-aware processors SHOULD prefer the specific properties given above, but MAY use the content in preference in cases where the properties above are incomplete or unsuitable.

3.3.  Base Activity Context Elements

This specification defines an initial set of activity context elements that can be used with all activity entries. These provide orthogonal context information that can apply to all activities.

3.3.1.  Location

Location is a concept which can be used inside the atom:entry level, atom:author and activity:object. Location can be specified via geographic coordinates, a street address, a free-form location name or a combination of these. Geographic coordinates should be included as a geo:point element as described by the GeoRSS specification. Addresses should be included using a poco:address element defined at Portable Contacts specification. The entry level location represents the location of the author at the time the activity was performed. The author level location represents the primary location of the author. Finally, the location within other objects represents the physical location of those objects. All location fields are optional. For free form addresses use the poco:formatted field.

Figure 1 (Location Example)

<entry>
  <id>tag:world:activity:1212121212121</id>
  <title>Rob liked Goldeberg's Deli</title>
  <author>
    <name>Rob Dolin</name>
    <id>tag:world:person:1212121212121</id>
    <link rel="alternate" type="text/html" href="http://robdolin.com" />
    <poco:address>
      <poco:locality>Marina del Rey</poco:locality>
      <poco:region>CA</poco:region>
      <poco:postalCode>90292</poco:postalCode>
      <poco:country>US</poco:country>
    </poco:address>
  </author>
  <activity:object>
    <activity:object-type>http://activitystrea.ms/schema/1.0/place</object-type>
    <id>tag:world:place:1212121212121</id>
    <title>Goldberg's Deli</title>
    <link rel="alternate" type="text/html" href="http://www.deli.com" />
    <geo:point>33.9777 -118.4351</geo:point>
    <poco:address>
      <poco:streetAddress>14016 Bora Bora Way</poco:streetAddress>
      <poco:locality>Marina del Rey</poco:locality>
      <poco:region>CA</poco:region>
      <poco:postalCode>90292</poco:postalCode>
      <poco:country>US</poco:country>
    </poco:address>
  </activity:object>
  <geo:point>33.9777 -119.4351</geo:point>
  <activity:verb>http://activitystrea.ms/schema/1.0/like</activity:verb>
</entry>

3.3.2.  Mood

Mood describes the mood of the user when the activity was performed. This is usually collected via an extra field in the user interface used to perform the activity. For the purpose of this schema, a mood is a freeform, short mood keyword or phrase along with an optional mood icon image.

Moods are included via a mood element in the namespace http://activitystrea.ms/context/.

The content of the mood element is the mood keyword or phrase.

The mood element may have an optional icon attribute which contains the URL of a mood icon image. The mood icon image SHOULD be small and appropriate to be displayed alongside the mood keyword at a normal text size.

3.4.  Replies

Most social applications have a concept of "comments", "replies" or "responses" to social Objects. In many cases these are simple text messages, but any Object can in practice be a reply.

A text-only reply SHOULD be represented using the comment object type as described in Section 3.2.4 (Comment). Replies of other types MUST carry the appropriate type and MUST NOT carry the comment object type.

Replies, regardless of object type, SHOULD be represented using the thr:in-reply-to element defined by [RFC4685] (Snell, J., “Atom Threading Extensions,” September 2006.). Publishers SHOULD also, if available, include metadata about the item being replied to using the mechanisms defined in [atomcommentmeta‑00] (Atkins, M., “Atom Comment Metadata Extensions,” .).

The act of posting a reply is represented by the post Verb as with "top-level" Objects.

4.  Event Schema

The event schema provides a vocabulary that is useful in applications that use real-world events and meetings as social objects.

4.1.  Event Verbs

4.1.1.  Positive RSVP

The "positive RSVP" verb indicates that the actor has made a positive RSVP for the object. This specification only defines the meaning of this verb when its object is an event (see Section 4.2.1 (Event)), though implementors SHOULD be prepared to handle other object types as meaning MAY be provided by extension specifications.

The use of this Verb is only appropriate when the RSVP was created by an explicit action by the actor. It is not appropriate to use this verb when a user has been added as an attendee by an event organiser or administrator.

The verb URI for the "positive RSVP" Verb is http://activitystrea.ms/schema/1.0/rsvp-yes.

4.1.2.  Possible RSVP

The "possible RSVP" verb indicates that the actor has made a possible RSVP for the object. This specification only defines the meaning of this verb when its object is an event (see Section 4.2.1 (Event)), though implementors SHOULD be prepared to handle other object types as meaning MAY be provided by extension specifications.

The use of this Verb is only appropriate when the RSVP was created by an explicit action by the actor. It is not appropriate to use this verb when a user has been added as an attendee by an event organiser or administrator.

The verb URI for the "possible RSVP" Verb is http://activitystrea.ms/schema/1.0/rsvp-maybe.

4.1.3.  Negative RSVP

The "negative RSVP" verb indicates that the actor has made a negative RSVP for the object. This specification only defines the meaning of this verb when its object is an event (see Section 4.2.1 (Event)), though implementors SHOULD be prepared to handle other object types as meaning MAY be provided by extension specifications.

The use of this Verb is only appropriate when the RSVP was created by an explicit action by the actor. It is not appropriate to use this verb when a user has been added as an attendee by an event organiser or administrator.

The verb URI for the "negative RSVP" Verb is http://activitystrea.ms/schema/1.0/rsvp-no.

4.2.  Event Object Types

4.2.1.  Event

The "event" object type represents an event that occurs in a certain place during a particular interval of time.

The object type URL for the "event" object type is http://activitystrea.ms/schema/1.0/event.

An event has the following properties:

name

The name of the event as provided by its organiser. Included as the content of the atom:title element.

start date and time

The date and time that the event begins. Included via a cal:dtstart element as defined in xCal.

end date and time

The date and time that the event ends. Included via a cal:dtend element as defined in xCal.

summary

A short description of the event as provided by its organiser. Included as the content of the atom:summary element.

5.  Music Schema

The music schema provides a vocabulary that is useful in applications that use music, musicians and albums as social objects.

5.1.  Music Object Types

5.1.1.  Song

The "song" Object type represents a song or a recording of a song.

Objects of type Song might contain information about the song or recording, or they might contain some representation of the recording itself. In the latter case, the song SHOULD also be annotated with the "audio" object type as described in Section 3.2.2 (Audio) and use its properties. This type should only be used when the publisher can guarantee that the object is a song rather than merely a generic audio stream.

The Object type URL for the "song" Object type is http://activitystrea.ms/schema/1.0/song.

A song has the following properties:

title

The title of the song. Included as the content of the atom:title element.

6. Normative References

Appendix A.  Acknowledgements

...

Authors' Addresses