xAPI Profiles 2.0 / Alignment to xAPI 2.0: Timestamps

[imartinezortiz]

Change Log Item Ids

s19, s20, s22

1.0.3 text -> 9274.1.1 Update

A Timestamp SHOULD* be expressed using the format described in RFC 3339, which is a profile of ISO 8601
->
A Timestamp shall be expressed using the format described in RFC 3339, which is a profile of ISO 8601.

A Timestamp SHOULD* include the time zone.
->
Removed as requirement

The LRS SHOULD* return the Timestamp in UTC timezone.
->
An LRS shall convert Timestamps to UTC rather than rejecting Statements that send Timestamps not in UTC form

Updates to xAPI Profile spec

• specify datatype (e.g. XSD dateTime vs dateTimeStamp) used for timestamps. What is the RDF type that is closest to RFC 3339?
• update Profile Server section to describe how it will handle timestamps not in the expected form

References to consider

• https://atom-syntax.imc.narkive.com/x8nvl4Bh/xsd-datetime-vs-rfc-3339
• https://narkive.com/x8nvl4Bh.26
• https://validator.w3.org/feed/docs/error/InvalidRFC3339Date.html

This issue has been migrated from: FeLungs#7

[imartinezortiz]

@FeLungs comment:

Overall, I think we should go with dateTimeStamp over dateTime because xAPI doesn't support timestamp without timezone or offset which IMO makes dateTimeStamp more correct than dateTime

dateTime

• https://www.w3.org/TR/xmlschema11-2/#dateTime
• Already used within xAPI Profile ontology for Profile Version generatedAt timestamp
• RDF built in

dateTimeStamp

The dateTimeStamp datatype is ·derived· from dateTime by giving the value required to its explicitTimezone facet. The result is that all values of dateTimeStamp are required to have explicit time zone offsets and the datatype is totally ordered.

• https://www.w3.org/TR/xmlschema11-2/#dateTimeStamp
• added in XSD 1.1

Both XSD types have differences from RFC 3339 but that can be accounted for within normative language. (example within explanation section of https://validator.w3.org/feed/docs/error/InvalidRFC3339Date.html)

• replace dateTime within profile context?
• informative + normative language for timestamps

https://www.w3.org/2011/rdf-wg/wiki/XSD_Datatypes

[andyjohnson]

WG Notes - Oct 24, 2024 -

1. Note that the current rfc is 9557 not 3339 as of April 2024
2. IEEE xAPI refers to 3339
3. Can review 9557 and look for changes
4. Recommend the timestamp property follows the xAPI timestamp in both the profile specification or JSON-LD