Atom Activity Streams 1.0

Abstract

This document presents an XML format that allows activities on social objects to be expressed within the Atom Syndication Format.

Table of Contents

1.  Introduction
    1.1.  Namespace and Version
    1.2.  Notational Conventions
2.  Activity Concepts
    2.1.  The Activity Construct
        2.1.1.  Time
        2.1.2.  Actor
        2.1.3.  Verb
        2.1.4.  Object
        2.1.5.  Target
        2.1.6.  Title
        2.1.7.  Summary
    2.2.  The Object Construct
        2.2.1.  ID
        2.2.2.  Name
        2.2.3.  Summary
        2.2.4.  Representative Image
        2.2.5.  Permalink URL
        2.2.6.  Object Type
3.  Atom Representation
    3.1.  Activity Representations
        3.1.1.  Full Activity Entry
        3.1.2.  Implied Activity Shorthand
    3.2.  Object Representations
        3.2.1.  Object Construct Representations
        3.2.2.  Common Representation for Object Construct Components
        3.2.3.  Object represented as atom:author
4.  RSS 2.0 Representation
    4.1.  Activity Construct Represented as RSS "item"
    4.2.  Object Construct Represented as RSS "item"
5.  Elements used in XML Representations
    5.1.  The activity:verb Element
        5.1.1.  Comparing activity:verb
    5.2.  The activity:object Element
    5.3.  The activity:object-type Element
        5.3.1.  Comparing activity:object-type
    5.4.  The activity:target Element
6.  The "Post" Verb
7.  Security Considerations
8.  IANA Considerations
9.  License
10.  Normative References
Appendix A.  Acknowledgements
Appendix B.  Examples
    B.1.  Full Activity Entry Examples
    B.2.  Implied Activity Entry Example
§  Authors' Addresses

1.  Introduction

The Atom Syndication Format, as defined in [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.), is widely used to transmit various types of web content such as weblog posts, news headlines, as well as user activities within social sites. In the case of user activities, Atom lacks the ability to express much of the activity-specific metadata in a machine-parseable format. Activity Streams is an XML format designed to allow this additional activity metadata to be expressed within existing Atom entries and feeds.

It is a goal of this specification to provide sufficient metadata about an activity such that a consumer of the data can present it to a user in a rich human-friendly format. This may include constructing readable sentences about the activity that occurred, visual representations of the activity, or combining similar activities for display.

1.1.  Namespace and Version

The XML Namespaces [xml‑names] (Bray, T., “Namespaces in XML 1.0 (Third Edition),” December 2009.) URI for the XML data format described in this specification is:

http://activitystrea.ms/spec/1.0/

For convenience, this data format may be referred to as "Atom Activities 1.0".

1.2.  Notational Conventions

This specification uses the namespace prefix "activity:" for the Namespace URI identified in Section 1.1 (Namespace and Version), and the namespace prefix "atom:" for the Namespace URI identified in Section 1.2 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.). Note that the choice of namespace prefixes is arbitrary and not semantically significant.

This specification uses a shorthand form of terms from the XML Infoset [xml‑infoset] (Cowan, J., “XML Information Set (Second Edition),” February 2004.). The term "element" is used to refer to an element information item, and "attribute" is used to refer to an attribute information item.

This specification allows the use of IRIs [RFC3987] (Duerst, M. and M. Suignard, “Internationalized Resource Identifiers (IRIs),” January 2005.). Every URI [RFC3986] (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifiers (URI): Generic Syntax,” January 2005.) 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] (Duerst, M. and M. Suignard, “Internationalized Resource Identifiers (IRIs),” January 2005.). When an IRI is serving as an identifier, it MUST NOT be so mapped.

The text of this specification provides the sole definition of conformance. Examples in this specification are non-normative.

This specification uses "Atom" to refer to [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.).

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 [RFC2119] (Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.).

2.  Activity Concepts

In its simplest form, an activity consists of an actor, a verb, and an object. It tells the story of a person performing an action on or with an object -- "Geraldine posted a photo" or "John shared a video". In most cases these elements will be explicitly declared, but they may also be implied.

2.1.  The Activity Construct

An activity consists of the following logical components:

2.1.1.  Time

A Date Construct, as defined in section 3.3 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.), that identifies the time at which the activity occurred. It is important to note that this is not necessarily the same as the time at which the activity was published. An Activity construct MUST have exactly one Time value.

2.1.2.  Actor

An Object Construct (The Object Construct) that identifies the entity that performed the activity. An Activity construct MUST have exactly one actor.

2.1.3.  Verb

An IRI reference that identifies the action of the activity. This value MUST be an absolute IRI, or a IRI relative to the base IRI of http://activitystrea.ms/schema/1.0/. An Activity construct MUST have exactly one verb.

2.1.4.  Object

This Object Construct (The Object Construct) identifies the primary object of the activity. An Activity construct MUST have exactly one object.

2.1.5.  Target

The target of an activity is an Object Construct (The Object Construct) that represents the object to which the activity was performed. The exact meaning of an activity's target is dependent on the verb of the activity, but will often be the object of the English preposition "to". For example, in the activity "John saved a movie to his wishlist", the target of the activity is "wishlist". The activity target MUST NOT be used to identify an indirect object that is not a target of the activity. An Activity construct MAY have a target but it MUST NOT have more than one.

2.1.6.  Title

An HTML representation of the natural language title for this activity. Consumers MAY use the value of this field, if set, as a fallback for when the provided verb is not recognized. An Activity Construct MAY have a title but it MUST NOT have more than one.

2.1.7.  Summary

An HTML representation of the activity, including visual elements such as thumbnails. Consumers MAY use the value of this field to present the activity to a user, in lieu of constructing a representation from each of the activity's components. Publishers SHOULD include a summary for activities in order to provide a fallback for parsers that are not Activity Streams aware. An Activity Construct MAY have a summary but it MUST NOT have more than one.

2.2.  The Object Construct

An object construct is a thing, real or imaginary, which participates in an activity. It may be the entity performing the activity, or the entity on which the activity was performed. An object consists of the logical components defined in the following sections. Certain object types may further refine the meaning of these components, or they may define additional components. If an object type defines an additional component then it SHOULD also define the representation of that component in one or more serialization formats.

2.2.1.  ID

The id of an object construct is an IRI that uniquely identifies the object. Note that the definition of "IRI" excludes relative references. An Object construct SHOULD have an ID value, and MUST NOT have more than one.

If an object construct does not have an ID value consumers MAY use the Permalink URL (Permalink URL) as a weaker identifier, but must in this case allow for the fact that Permalink URL is not defined to be unique across all objects and be prepared to handle duplicates.

2.2.2.  Name

This string value provides a human readable display name for the object, if the object has a name. An Object construct MAY have a name, but MUST NOT have more than one.

2.2.3.  Summary

This string value provides a human readable description or summary of the Object. An Object construct MAY have a summary, but MUST NOT have more than one.

2.2.4.  Representative Image

This IRI reference identifies an image resource which provides a visual representation of the object, intended for human consumption. An Object construct MAY have a representative image, but MUST NOT have more than one.

2.2.5.  Permalink URL

This IRI reference identifies a resource which provides an HTML representation of the object. An Object construct MAY have a Permalink URL, but MUST NOT have more than one.

2.2.6.  Object Type

An IRI reference that identifies the type of object. This value MUST be an absolute IRI, or a IRI relative to the base IRI of http://activitystrea.ms/schema/1.0/. An Object construct MAY have a type, but MUST NOT have more than one.

If no object type is present, the object has no specific type. Consumers SHOULD refer to such objects only by their names. For example, when forming an activity sentence a consumer might say "Johan posted 'My Cat'" rather than "Johan posted a photo: 'My Cat'".

3.  Atom Representation

Activities can be represented in an Atom document using a combination of conventions and custom extension elements. This specification defines two ways that an activity can be represented using atom:entry elements, as a Full Activity Entry or using Implied Activity Shorthand. Other specifications may define additional representations.

3.1.  Activity Representations

Any valid Atom entry as defined by section 4.1.2 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.) is a representation of an activity as defined in Section 2.1 (The Activity Construct).

If the atom:entry contains an activity:object element then it is a Full Activity Entry and MUST be interpreted as described in Section 3.1.1 (Full Activity Entry). Otherwise the entry is an Implied Activity Shorthand Entry and MUST be interpreted as described in Section 3.1.2 (Implied Activity Shorthand).

3.1.1.  Full Activity Entry

A Full Activity Entry is one in which the atom:entry represents the full Activity Construct (The Activity Construct). The components of the activity are represented by child elements of the atom:entry. In this section, "the entry" refers to the atom:entry element that represents the Full Activity Entry.

The components of the Activity Construct are represented in a Full Activity Entry as follows:

Actor

The Actor (Actor) of the Activity Construct is represented by the atom:author element that applies to the entry, as defined by section 4.2.1 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.). The representation of an Object Construct as an atom:author element is defined in Section 3.2.3 (Object represented as atom:author).

Object

The Object (Object) of the Activity Construct is represented by the activity:object child element of the entry, as defined in Section 5.2 (The activity:object Element).

Target

The Target (Target) of the Activity Construct is represented by the activity:target child element of the entry, as defined in Section 5.4 (The activity:target Element). If no such element is present, the Activity Construct has no Target.

Verb

The verb IRI (Verb) of the Activity Construct is represented by an activity:verb child element as defined in Section 5.1 (The activity:verb Element). If the entry has no activity:verb child element, then the Activity Construct has the "Post" verb as defined in Section 6 (The "Post" Verb).

Time

The Time (Time) of the Activity Construct is represented by the atom:published child element of the entry, as defined in section 4.2.9 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.).

Title

The Title (Title) of the Activity Construct is represented by the atom:title child element of the entry, as defined in section 4.2.14 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.). Consumers MUST convert the value into HTML if necessary.

Summary

The Summary (Summary) of the Activity Construct is represented either by the atom:content or atom:summary child element of the entry, as defined in section 4.1.3 and section 4.2.13 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.) respectively. If atom:summary is present it MUST contain the summary of the Activity Construct. If atom:summary is not present then the atom:content element MUST contain the summary of the Activity Construct. Consumers MUST convert the value into HTML if necessary.

3.1.2.  Implied Activity Shorthand

An implied activity shorthand entry represents an Activity Construct in terms of its object. In this mode, the atom:entry primarily represents the Object Construct that is the object of the Activity Construct, but also represents certain additional components of the Activity Construct. In this section, "the entry" refers to the atom:entry element.

The components of the Activity Construct are represented in an Implied Activity Shorthand Entry as follows:

Actor

The Actor (Actor) of the Activity Construct is represented by the atom:author element that applies to the entry, as defined by section 4.2.1 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.). The representation of an Object Construct as an atom:author element is defined in Section 3.2.3 (Object represented as atom:author).

Object

The Object (Object) of the Activity Construct is represented by the entry itself. The representation of an Object Construct as an atom:entry element uses the child elements defined in Section 3.2.2 (Common Representation for Object Construct Components).

Target

The Activity Construct does not have a Target (Target).

Verb

The verb IRI (Verb) of the Activity Construct is represented by an activity:verb child element as defined in Section 5.1 (The activity:verb Element). If the entry has no activity:verb child element, then the Activity Construct has the "Post" verb as defined in Section 6 (The "Post" Verb).

Time

The Time (Time) of the Activity Construct is represented by the atom:published child element of the entry, as defined in section 4.2.9 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.).

Title

The Activity Construct does not have a Title (Title).

Summary

The Activity Construct does not have a Summary (Summary).

The Implied Activity Shorthand is an accommodation to allow activity metadata to be added to a feed that is considered by traditional Atom consumers to be a list of content objects rather than a list of activities, without changing the meaning of that feed. Such feeds can often be recognized by the fact that the atom:title element of each entry is the title of an object rather than a sentence describing an activity.

3.2.  Object Representations

Object constructs (The Object Construct) are used to identify a number of different components in an activity, including the Actor (Actor) and Object (Target) of an activity, among others. Depending on what an object is used to identify, it is rendered in Atom using a different root element, as defined in Section 3.2.1 (Object Construct Representations). The components of the object are represented using child elements as defined in Section 3.2.2 (Common Representation for Object Construct Components).

3.2.1.  Object Construct Representations

Object constructs can be represented using the following elements:

atom:entry

When used to describe the object of an Implied Activity as defined in Section 3.1.2 (Implied Activity Shorthand), an Object Construct is represented using the atom:entry element, using the elements defined in Section 3.2.2 (Common Representation for Object Construct Components).

atom:author

When used to describe the Actor of an Activity Construct (Actor), an Object Construct is represented using the atom:author element, as defined in Section 3.2.3 (Object represented as atom:author).

activity:object

When used to describe the Object of an Activity Construct (Object), an Object Construct is represented using the activity:object element as defined in Section 5.2 (The activity:object Element).

activity:target

When used to describe the Target of an Activity Construct (Target), an Object Construct is represented using the activity:target element as defined in Section 5.4 (The activity:target Element).

other elements

Other specifications or object types may define additional elements that can be used to represent objects.

The element used to represent the Object MAY have additional attributes and child elements that represent properties defined by the Object Type of the Object or by other extensions. These extensions are defined by the Atom representation provided for the Object Type or extension.

3.2.2.  Common Representation for Object Construct Components

Unless specified otherwise, the components of an Object Construct are represented using child elements of the representative element as follows, regardless of the type of element used to describe the Object Construct:

ID

The ID (ID) of the Object Construct is represented using the atom:id element, as defined in section 4.2.6 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.).

Name

The name (Name) of the Object Construct is represented using the atom:title element, as defined in section 4.2.14 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.). Consumers MUST convert the value into HTML if necessary.

Summary

The summary (Summary) of the Object Construct is represented using the atom:summary element, as defined in section 4.2.13 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.). Consumers MUST convert the value into HTML if necessary.

Representative Image

The representative image (Representative Image) of the Object Construct is represented by the first atom:link element whose rel attribute value is "preview" and a whose type attribute value is an image media type.

Permalink URL

The permalink URL (Permalink URL) of the Object Construct is represented by the href attribute of an atom:link element, whose rel attribute value is "alternate" and whose type attribute value is "text/html".

Object Type

The object type URL (Object Type) of the Object Construct is represented by an activity:object-type element as defined in Section 5.3 (The activity:object-type Element).

3.2.3.  Object represented as atom:author

When used to describe the Actor of an Activity (Actor), an Object Construct is represented using the atom:author element (see section 4.2.1 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.)). The components of the Object Construct are represented using child elements as defined in Section 3.2.2 (Common Representation for Object Construct Components), with the following exceptions:

Name

The name of the Object Construct is represented using the atom:name element, as defined in section 3.2.1 of [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.).

Permalink URL

The URL of the Object Construct is represented by the href attribute of an atom:link element, whose rel attribute value is "alternate" and a whose type attribute value is "text/html". If no such atom:link element is present, consumers SHOULD accept the content of the atom:uri element as representing the Object Permalink URL.

4.  RSS 2.0 Representation

Activities can be represented in an RSS 2.0 document, as defined by [RSS2] (, “RSS 2.0 Specification,” March 2009.), using a combination of conventions and custom extension elements. An activity is represented using an RSS "item" element. The RSS serialization only supports a subset of the activity data model allowing descriptions of simple activities that have only a verb and an object. This serialization is optimized for posting activities describing the creation of new objects. Publishers with a need for representing other fields that are not catered for by this serialization are recommended to use the Atom serialization instead for best results. This RSS serialization is defined only as a means for those already publishing streams of objects as RSS to produce minimally useful lists of activities for activity-aware consumers.

A specific RSS document has a single activity actor that applies to all activities it represents. This actor has no known id, name, url or object type but it is assumed that all activities in the feed share the same actor and therefore consumers MAY use information obtained from another source, such as the user account which is assumed to be the subject of the feed, to populate these properties.

4.1.  Activity Construct Represented as RSS "item"

In this section, "the item" refers to the RSS "item" element which is representing the activity.

An RSS "item" element represents exactly one Activity Construct in terms of its object. The item actually directly represents both the Object Construct that is the object of the Activity Construct and the Activity Construct itself via different subsets of the child elements.

The components of the Activity Construct are represented in an RSS item as follows:

Actor

The Actor (Actor) of the Activity Construct is the feed-wide actor as described in Section 4 (RSS 2.0 Representation).

Object

The Object (Object) of the Activity Construct is represented by the item itself. The representation of an Object Construct as an RSS item element is defined in Section 4.2 (Object Construct Represented as RSS "item").

Target

The Activity Construct does not have a Target (Target).

Verb

The verb IRI (Verb) of the Activity Construct is represented by an activity:verb child element as defined in Section 5.1 (The activity:verb Element). If the item has no activity:verb child elements then the Activity Construct has only the "Post" verb as defined in Section 6 (The "Post" Verb).

Time

The Time (Time) of the Activity Construct is represented by the pubDate child element of the item, as defined in [RSS2] (, “RSS 2.0 Specification,” March 2009.).

Title

The Activity Construct does not have a Title (Title).

Summary

The Activity Construct does not have a Summary (Summary).

4.2.  Object Construct Represented as RSS "item"

The components of an Object Construct are represented using child elements of an RSS item element as follows:

ID

The ID (ID) of the Object Construct is represented using the RSS guid element, as defined in [RSS2] (, “RSS 2.0 Specification,” March 2009.), if and only if its value conforms to the syntax of an IRI as defined in [RFC3987] (Duerst, M. and M. Suignard, “Internationalized Resource Identifiers (IRIs),” January 2005.). If the value is not a valid IRI then the Object Construct has no ID.

Name

The name (Name) of the Object Construct is represented using the RSS title element, as defined in [RSS2] (, “RSS 2.0 Specification,” March 2009.).

Summary

The Object Construct has no summary (Summary).

Representative Image

The representative image (Representative Image) of the Object Construct is represented by the href attribute of an atom:link element, whose rel attribute value is "preview" and a whose type attribute value is an appropriate image media type.

Permalink URL

The permalink URL (Permalink URL) of the Object Construct is represented by the first RSS link child element, as defined in [RSS2] (, “RSS 2.0 Specification,” March 2009.). If no such element is present, the value of the first guid child element that is marked as a permalink as defined in [RSS2] (, “RSS 2.0 Specification,” March 2009.) represents the Permalink URL. If neither element is present, the Object Construct has no Permalink URL.

Object Type

Each object type URL (Object Type) of the Object Construct is represented by an activity:object-type element as defined in Section 5.3 (The activity:object-type Element).

5.  Elements used in XML Representations

This specification defines several elements in the XML namespace defined in Section 1.1 (Namespace and Version). These elements are used in both the Atom and RSS serializations and may be used by other XML-based serializations of the activity streams data model defined by other specifications.

5.1.  The activity:verb Element

The activity:verb element represents the Verb of an Activity Construct as defined in Section 2.1.3 (Verb). Its content is an IRI reference that identifies the verb.

5.1.1.  Comparing activity:verb

The value of activity:verb elements can be used to determine whether an Activity construct contains a recognized verb. Processors MUST compare activity:verb elements on a character-by-character basis (in a case-sensitive fashion). Comparison operations MUST be based solely on the IRI character strings and MUST NOT rely on dereferencing the IRIs or URIs mapped from them. As a result, two IRIs that resolve to the same resource but are not character-for-character identical will be considered different for the purposes of identifier comparison.

Processors SHOULD resolve relative IRIs to their absolute form using the base http://activitystrea.ms/schema/1.0/ prior to comparison. For example, processors SHOULD consider the following IRIs as equivalent for the purpose of comparison:

• http://activitystrea.ms/schema/1.0/post
• post

5.2.  The activity:object Element

An activity:object element represents the Object Construct that is the Object of an Activity Construct as defined in Section 2.1.4 (Object).

The content model of an activity:object element includes the elements indicated in Section 3.2.2 (Common Representation for Object Construct Components), with the meanings defined in that section, as well as any extension elements defined by the Atom serializations of the object type listed for the object.

5.3.  The activity:object-type Element

An activity:object-type element represents the Object Type of an Object Construct as defined in Section 2.2.6 (Object Type). Its content is an IRI reference that identifies the object type.

5.3.1.  Comparing activity:object-type

The value of activity:object-type elements can be used to determine whether an Object construct is of a recognized type. Processors MUST compare activity:object-type elements using the same comparison rules described in Section 5.1.1 (Comparing activity:verb).

5.4.  The activity:target Element

An activity:target element represents the Object Construct that is the Target of an Activity Construct as defined in Section 2.1.5 (Target).

The content model of an activity:target element includes the elements indicated in Section 3.2.2 (Common Representation for Object Construct Components), with the meanings defined in that section, as well as any extension elements defined by the Atom serializations of the object type listed for the object.

6.  The "Post" Verb

This specification defines one initial verb and defers to other specifications to define the full schema of verbs and object types.

The "Post" verb describes the act of authoring an object and then publishing it online. The IRI reference for the "Post" verb is:

post

The actor of an Activity Construct using the "Post" verb is an Object Construct representing the person or object that authored and posted the item represented by the object of the Activity Construct.

The target of the Activity Construct, if present, represents the item into which the object is posted. For example, this could represent a blog that the author has posted in.

7.  Security Considerations

As this specification defines an extension to the Atom Syndication Format, it is subject to the same security considerations defined in [RFC4287] (Nottingham, M. and R. Sayre, “The Atom Syndication Format,” December 2005.).

Publishers or Consumers implementing Activity Streams as a stream of public data may also want to consider the potential for unsolicited commercial or malicious content and should take preventative measures to recognize such content and either identify it or not include it in their stream implementations.

Publishers should take reasonable measures to make sure potentially malicious user input such as cross-site scripting attacks are not included in the Activity Streams data they publish.

Consumers that re-emit ingested content to end-users MUST take reasonable measures if emitting ingested content to make sure potentially malicious ingested input is not re-emitted.

Consumers that re-emit ingested content for crawling by search engines should take reasonable measures to limit any use of their site as a Search Engine Optimization loophole. This may include converting un-trusted hyperlinks to text or including a rel="nofollow" attribute.

8.  IANA Considerations

None.

9.  License

As of [date], the following persons or entities have made this Specification available under the Open Web Foundation Agreement Version 1.0, which is available at http://www.openwebfoundation.org/legal/.

[List of persons or entities]

You can review the signed copies of the Open Web Foundation Agreement Version 1.0 for this Specification at http://activitystrea.ms/licensing/, which may also include additional parties to those listed above.

Your use of this Specification may be subject to other third party rights. THIS SPECIFICATION IS PROVIDED “AS IS.” The contributors expressly disclaim any warranties (express, implied, or otherwise), including implied warranties of merchantability, non-infringement, fitness for a particular purpose, or title, related to the Specification. The entire risk as to implementing or otherwise using the Specification is assumed by the Specification implementer and user. IN NO EVENT WILL ANY PARTY BE LIABLE TO ANY OTHER PARTY FOR LOST PROFITS OR ANY FORM OF INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OF ANY CHARACTER FROM ANY CAUSES OF ACTION OF ANY KIND WITH RESPECT TO THIS SPECIFICATION OR ITS GOVERNING AGREEMENT, WHETHER BASED ON BREACH OF CONTRACT, TORT (INCLUDING NEGLIGENCE), OR OTHERWISE, AND WHETHER OR NOT THE OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

10. Normative References

Appendix A.  Acknowledgements

The authors wish to thank the Activity Streams community and implementers for their support, encouragement, and enthusiasm including but not limited to: Abdul Qabiz, Adina Levin, Adrian Chan, Adriana Javier, Alexandre Loureiro Solleiro, Ari Steinberg, Arne Roomann-Kurrik, Beau Lebens, Ben Hedrington, Ben Metcalfe, Ben Werdmuller, Bill de hÓra, Bob Aman, Bob Wyman, Brynn Evans, Charlie Cauthen, Chris Chabot, Christian Crumlish, Dan Brickley, Danny Ayers, Dare Obasanjo, Darren Bounds, David Cramer, David Recordon, DeWitt Clinton, Douglas Pearce, Ed Summers, Elias Bizannes, Elisabeth Norris, Eric Woods, Evan Prodromou, Gee-Hsien Chuang, Greg Biggers, Hillary Madsen, Howard Liptzin, Ian Kennedy, Ivan Pulleyn, Jacob Kim, James Falkner, James Walker, Jason Kahn, Jeff Kunins, Jian Lin, John Panzer, Jon Paul Davies, Jonathan Coffman, Jonathan Dugan, Joseph Boyle, Joseph Hosten, Joseph Smarr, Jud Valeski, Julien Genestoux, Jyri Engeström, Kaliya Hamlin, Kevin Marks, Laurent Eschenauer, Manu Mukerji, Mark Weitzel, Marshall Kirkpatrick, Mary Hoder, Matt Leventi, Matt Wilkinson, Matthias Muller-Prove, Max Engel, Melvin Carvalho, Michael Richardson, Nate Benes, NeilFred Picciotto, Nick Lothian, Nissan Dookeran, Nitya Narasimhan, Pablo Martin, Pat G. Cappalaere, Peter Ferne, Peter Reiser, Peter Saint-Andre, Phil Wolff, Philip (flip) Kromer, Rick Severson, Robert Langbert, Todd Barnard, Ryan Boyd, Sam Sethi, Scott Raymond, Scott Seely, Simon Grant, Simon Wistow, Stephen Garcia, Steve Ivy, Steven Livingstone-Perez, Sylvain Carle, Sylvain Hellegouarch, Tantek Celik, Tatu Saloranta, Tim Moore, Timothy Young, Todd Barnard, Tosh Meston, and Tyler Gillies.

Appendix B.  Examples

This appendix is non-normative.

B.1.  Full Activity Entry Examples

A typical activity entry:

<entry xmlns="http://www.w3.org/2005/Atom" xmlns:activity="http://activitystrea.ms/spec/1.0/">
  <id>tag:photopanic.example.com,2009:activity/4859/4352</id>
  <title>Geraldine posted a Photo on PhotoPanic</title>
  <published>2009-11-02T15:29:00Z</published>
  <link rel="alternate" type="text/html" href="http://example.com/geraldine/activities/4352" />
  <activity:verb>post</activity:verb>
  <activity:object>
    <id>tag:photopanic.example.com,2009:photo/4352</id>
    <title>My Cat</title>
    <published>2009-11-02T15:29:00Z</published>
    <link rel="alternate" type="text/html" href="http://example.com/geraldine/photos/4352" />
    <activity:object-type>photo</activity:object-type>
  </activity:object>
  <content type="html">
    &lt;p&gt;Geraldine posted a Photo on PhotoPanic&lt;/p&gt;
    &lt;img src="/geraldine/photos/4352.jpg"&gt;
  </content>
</entry>

This example shows a typical activity entry using the post verb defined by this specification and a hypothetical "photo" object type. It also demonstrates the use of atom:title and atom:content to provide fallback content for feed processors that do not support activity extensions. An activity stream application might render this entry into the sentence "Geraldine posted a photo titled 'My Cat'", with the photo title presented as a link.

A slightly more complex activity entry:

<entry xmlns="http://www.w3.org/2005/Atom" xmlns:activity="http://activitystrea.ms/spec/1.0/">
  <id>tag:photopanic.example.com,2009:/activity/4859/1643</id>
  <title>Geraldine posted a photo to the My Pets album.</title>
  <published>2010-06-21T00:28:35Z</published>
  <link rel="alternate" type="text/html" href="http://example.com/geraldine/activities/1643" />
  <author>
    <name>Geraldine</name>
    <uri>http://example.com/geraldine</uri>
    <id>tag:photopanic.example.com,2009:person/4859</id>
    <activity:object-type>person</activity:object-type>
    <link rel="alternate" type="text/html" href="http://example.com/geraldine" />
  </author>
  <activity:object>
    <id>tag:photopanic.example.com,2009:photo/1643</id>
    <title>My Cat</title>
    <link rel="alternate" type="text/html" href="/geraldine/photos/1643" />
    <link rel="preview" type="image/jpeg" href="/geraldine/photos/1643/thumb.jpg" />
    <link rel="enclosure" type="image/jpeg" href="/geraldine/photos/1643/full.jpg" />
    <activity:object-type>photo</activity:object-type>
  </activity:object>
  <activity:target>
    <id>tag:photopanic.example.com,2009:photo-album/2519</id>
    <title>My Pets</title>
    <link rel="alternate" type="text/html" href="/geraldine/albums/pets" />
    <activity:object-type>photo-album</activity:object-type>
  </activity:target>
  <content type="xhtml">...</content>
</entry>

This example demonstrates the use of the actor, verb, object and target elements.

B.2.  Implied Activity Entry Example

A simple implied activity entry:

<entry xmlns="http://www.w3.org/2005/Atom" xmlns:activity="http://activitystrea.ms/spec/1.0/">
  <id>tag:photopanic.example.com,2009:photo/4352</id>
  <title>My Cat</title>
  <published>2010-11-02T15:29:00Z</published>
  <link rel="alternate" type="text/html" href="http://example.com/geraldine/photos/4352" />
  <activity:object-type>photo</activity:object-type>
</entry>

This example shows the same activity from Appendix B.1 (Full Activity Entry Examples), but represented using the implied activity shorthand. Note that some of the components of the Activity Construct, such as title and summary, are not supported by this representation.

Authors' Addresses