Session Date/Time: 10 Nov 2021 14:30

calext

Summary

The calext working group session focused on updates and next steps for several drafts. Key discussions revolved around technical clarifications for the relations draft, necessary refactoring for iCal Tasks, stalled progress on the JS Calendar mapping, and preparation for a Working Group Last Call (WGLC) for Subscription Upgrade. The group also discussed future work, including the refresh of core iCalendar RFCs (5545, 5546) and the creation of a calendaring data model document. A significant outcome was the consensus to recharter the working group to be a long-running entity responsible for general calendaring-related work and maintenance.

Key Discussion Points

iCalendar Relations (draft-dawes-icalendar-relations)
- Security Section: A comment suggested adding information on XML security perils due to an XML reference in the draft. No specific issue was highlighted, but a generic warning about XML entities (referencing the WebDAV spec) was proposed for inclusion. The group agreed this general statement should suffice, with further review during IESG processing.
- Link Property Serialization: Discussed Mark Nottingham's comment regarding the link property as a serialization of RFC 8288's link header. The group agreed that the draft is a reasonable serialization, using FORMAT-TYPE for type and LABEL for title. Explicitly stating UTF-8 encoding avoids the need for title* parameters. There is no need to define a new registry.
- Useful Link Relations: Identified several existing link relations that could be immediately useful for calendaring, especially in event publication: copyright, terms-of-service, privacy-policy, author, payment, and a proposed source relation to link back to the origin of an event.
- Action: Mike to update the draft with the security section text, explicit serialization details for FORMAT-TYPE and LABEL, and potentially add clarification on the source relation. A new draft version is expected within 2-3 days.
- JS Calendar Interdependency: Noted that JS Calendar also references RFC 8288, implying a need to align its reference to the updated relations draft.
iCal Tasks (draft-dawes-icalendar-tasks)
- The draft has been dormant and requires substantial updates.
- Relations Integration: Needs to be updated to refer to the newer relations work.
- Participant Component: The GROUP parameter for status grouping should be replaced with the PARTICIPANT component, which provides a more robust and less crude method for grouping properties, especially for per-attendee status.
- Enhanced Status: The STATUS property in iCalendar is limited. The draft should introduce a new component to group more complex status information, including associated comments, similar to concepts in JS Calendar.
- Alignment: Needs to stay aligned with JMAP tasks work.
- Action: Mike to continue significant rewriting and updating of the document.
JS Calendar <-> iCalendar Mapping (draft-ietf-calext-jscalendar-icalendar-mapping)
- No progress since the last interim meeting; still in the design phase for JS Calendar to iCalendar mapping.
- Implementation Experience: Requires implementation experience for advancement. Cyrus IMAP server (Robert) and another implementation (Mike) are targeted for this.
- Dependencies: The link object mapping in JS Calendar depends on the updates being made to the relations draft.
- Action: Robert and Mike will collaborate to prioritize and push forward with implementations and spec updates.
Subscription Upgrade (draft-ietf-calext-subscription-upgrade)
- The draft is considered to be in a good state, with current open issues being more matters of opinion than substantive technical changes.
- Next Steps: Mike will perform a final review, refresh the dates, and publish a new version, after which the document will be proposed for Working Group Last Call (WGLC).
Future Work
- VPOLL (draft-ietf-calext-vpoll): Mike has updated the draft to use the PARTICIPANT component instead of a custom VOTER component, improving consistency.
  - Action: Mike to publish a new version. Robert (Cyrus) will update his implementation by the next IETF for interoperability testing.
- Server-Side Subscription (draft-ietf-calext-server-side-subscription): Awaiting feedback from Apple.
- RFC 5545/5546 Refresh: Brian suggested that core iCalendar RFCs (5545/5546) are due for a refresh, citing 17 errata and updates from 75 other specs for 5545. He also noted the need for updated language in 5546 regarding handling invites/replies on behalf of others, especially with DMARC/IMAP contexts.
- Calendaring Data Model Document: Mike proposed creating a document that defines the calendaring data model independent of its representation (e.g., iCalendar, JS Calendar). This would clarify the underlying semantics, similar to how HTTP/S separates wire format from semantics, and would be valuable for future formats. An existing OASIS WS-Calendar Platform Independent Model (PIN) was mentioned as a potential starting point.
- iTIP with JS Calendar: Discussion included extending JS Calendar to support iTIP exchange, possibly as a text alternative.
Working Group Rechartering
- The current charter is highly specific, which necessitates rechartering for new work items.
- Consensus: There was strong agreement to recharter the calext working group to be a broad, long-running working group responsible for all calendaring-related standards, including maintenance of existing documents, extensions, and new work. This will avoid frequent rechartering and provide a clear home for calendaring work.
- Action: Brian to draft a recharter proposal and discuss it with Daniel.

Decisions and Action Items

Decisions

The iCalendar Relations draft will not define a new link registry but will explicitly state its serialization of RFC 8288's link header using existing iCalendar properties (FORMAT-TYPE and LABEL).
The calext working group will pursue rechartering to become a long-running working group with a broader scope encompassing general calendaring-related standards, maintenance, and extensions.

Action Items

Mike Dawes:
- Update draft-dawes-icalendar-relations with security section clarification and explicit link header serialization details. Publish a new draft within 2-3 days.
- Follow up on the alignment of JS Calendar's RFC 8288 references with the updated relations draft.
- Continue significant refactoring and updating of draft-dawes-icalendar-tasks (integrating relations, PARTICIPANT component, enhanced status).
- Perform a final review and refresh dates for draft-ietf-calext-subscription-upgrade in preparation for WGLC.
- Publish a new version of draft-ietf-calext-vpoll incorporating the PARTICIPANT component.
- Collaborate with Robert on draft-ietf-calext-jscalendar-icalendar-mapping implementations and updates.
Robert Scheck:
- Prioritize updating the Cyrus IMAP server implementation for draft-ietf-calext-jscalendar-icalendar-mapping.
- Update Cyrus IMAP implementation of draft-ietf-calext-vpoll by the next IETF for interoperability testing.
- Collaborate with Mike on draft-ietf-calext-jscalendar-icalendar-mapping implementations and updates.
Brian Rosen:
- Draft a proposal for rechartering the calext working group and discuss it with Daniel (AD).

Next Steps

Draft Publication: Anticipate updated versions of draft-dawes-icalendar-relations, draft-dawes-icalendar-tasks, draft-ietf-calext-subscription-upgrade, and draft-ietf-calext-vpoll in the coming weeks.
Working Group Last Call (WGLC): Begin WGLC for draft-ietf-calext-subscription-upgrade after Mike's final review.
Implementation: Push forward with implementations for draft-ietf-calext-jscalendar-icalendar-mapping to gather essential experience.
Rechartering: Initiate the process for rechartering the calext working group.
Milestone Review:
- draft-dawes-icalendar-tasks: Target submission to IESG by January.
- draft-ietf-calext-subscription-upgrade: Target submission to IESG by December/January.
- draft-ietf-calext-jscalendar-icalendar-mapping: Aim for completion by April (next IETF).
- draft-dawes-icalendar-series: Milestone adjusted to July.
- draft-ietf-calext-vpoll: Current milestone (June 2022) remains.
- draft-ietf-calext-server-side-subscription: Status pending Apple feedback.