Foreword
The Calendaring and Scheduling Consortium (“CalConnect”) is a global non-profit organization with the aim to facilitate interoperability of technologies across user-centric systems and applications.
CalConnect works closely with liaison partners including international organizations such as ISO, OASIS and M3AAWG.
The procedures used to develop this document and those intended for its further maintenance are described in the CalConnect Directives.
In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the CalConnect Directives.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CalConnect shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the CalConnect list of patent declarations received (see www.calconnect.com/patents).
Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.
This document was prepared by Technical Committee CALCONNECT.
Introduction
NOTE Following CalConnect XXIX in February, the term “Roundtable” was replaced by “Conference” or “CalConnect Conference”.
CalConnect Conference XXXI took place on October 1-3, 2014, hosted by Youcanbook.me in Bedford, United Kingdom.. The CalConnect Conference was attended by 19 people from 13 members. The Interoperability Test Event was held immediately prior to the Conference on September 29 — October 1, February 3-5, and had 15 participants onsite from 9 members; an additional 4 people from 3 members attended the test event remotely. In total, 21 people from 13 organizations attended some portion of the week.
The Conference consisted primarily of technical committee sessions, workshops and BOFs. In addition a live demonstration of work under development was offered, plus a BoF (Birds of a Feather Session) and two Workshops. The sessions were as usual organized sequentially without competing parallel sessions, as is our standard practice, to allow all attendees who wished to be involved in the discussions of each Technical Committee the opportunity to do so. The Conference finished with the CalConnect Plenary Session on Friday afternoon.
Report on CalConnect Conference XXXI, October 1-3, 2014
1. Special Events
Two Workshops were held on Thursday morning and Friday morning: Groups Scheduling and Sharing and History and Comment Feeds in iCalendar. A Birds of a Feather session on developing a unified Calendaring Scheduling Architecture was also held on Friday. A retrospective presentation on the Veterans’ Administration Health Care Workshop held at CalConnect XXX in May was also offered on Thursday.
2. Documents since Last Roundtable
Much of the work in CalConnect is focused on specifications to become internet draft submissions to the IETF and ultimately be progressed to become RFCs (Proposed Standards), rather than be directly published by CalConnect itself.
2.1. Published Documents
Report on CalConnect Conference XXX
Report on Interoperability Test Event XXX
7 Things You Should Know About the Abstract Calendaring API
Updated Starter List of CalDAV and CardDAV Standards and Specifications
3. Update on Technical Committee Work and Initiatives Including BOFs and Workshops
3.1. BOF on Calendaring & Scheduling Architecture
The BOF discussed whether Tasks and Events are different concepts or simply the same thing with different details. Tasks can but don’t have to be time-based; Events might not have a start or end date especially with VAVAILABILITY/VPOLL. Our architecture document should start with the model rather than from the user perspective; an interactive diagram would be nice to avoid a too-rich diagram. The architecture is currently under the auspices of TC API.
3.2. CALSCALE Ad Hoc
No session was held at the conference. The Ad Hoc is on hold pending progression of the RSCALE draft now adopted as a CALEXT Working Group draft in the IETF for progression to become an RFC: Non-Gregorian Recurrence Rules in iCalendar.
3.3. ITINERARY Ad Hoc
No session was held at the conference. The goal is to improve the user experience with itinerary info from travel sites by extending iCalendar to incorporated needed information; however, we need input from travel industry experts on what is needed. The Ad Hoc continues to look for experts to inform the work.
3.4. TC API
The TC offered an overview of work since the last conference, including data objects, relations and operations. Details about the REST API we have been discussing were reviewed, and fruux gave a demo on their REST API. YCBM (Youcanbook.me) provided a demo on Calligraph, a tool they have developed to federate multiple calendar sources.
3.5. TC AUTODISCOVERY
No TC session was held at this conference. The TC has produced an initial draft of a mechanism for multiple service discovery via a single protocol for client setup and submitted to the IETF: Aggregated Service Discovery. We are waiting for an opportunity to move this forward at the IETF.
3.6. TC CALDAV
Several topics were discussed in the session.
Server-Info document: The basic outline was presented and discussed. A discussion of where the document should “live” ensued. The consensus is to define a WebDAV property and also use a Link header in the OPTIONS response. Another discussion was about whether to include “constant” properties. The TC will research current client PROPFINDs and then see what is best, but probably scope it as close as possible to the impacted resources.
Scheduling Drafts: The basic outline of a solution was presented and discussed. The overall feeling was to initially move forward with the approach for new drafts only. The TC will do more work on how best to handle the “lost update” problem when creating drafts from existing resources.
Calendar Principal Searching: All agreed that DAV:principal-property-search is too structured and something better is needed. The TC will look into whether the existing report can be augmented with a custom property or a new report should be created (e.g. standardizing the calendarserverprincipalsearch report).
Discussion of the status of WebDAV Prefer Draft and whether return=representation should be allowed on a precondition failure. The consensus was that it should be allowed to eliminate the need for the client to fetch the new resource in a separate request. The draft will be refreshed, reviewed and submitted to IETF.
Discussion on use of patch/diffs for client updates and whether ETag, Schedule-Tag is sufficient for that. The TC will investigate formalizing a diff format for CalDAV with a preference for a JSON-based solution.
3.7. TC EVENTPUB
TC EVENTPUB summarized the state of its current drafts; the TC has been dormant as we wait for the backlog of drafts before the IETF to clear. There was some discussion about the new CONFERENCE property and colors. The current EVENTPUB drafts referenced above are Event Publication Extensions to iCalendar and New Properties for iCalendar.
3.8. TC FREEBUSY
The TC reviewed the draft specification: VPOLL: Consensus Scheduling Component for iCalendar and the BASIC poll mode, then presented some of the thoughts we have had in the TC and also in TC TASKS about a new task assignment poll mode. We also talked about signup modes which could support informal event planning, and discussed the possible use of VPOLL for simple resource management. The TC also offered a quick demo of a VPOLL client.
3.9. TC FSC
TC FSC (Federated Shared Calendars) was formed from the FSC Ad Hoc Committee following CalConnect XXX. The TC presented the current design for federated shared calendars. There was a lot of discussion of enhancing subscribed calendar behavior versus using CalDAV, with the consensus moving towards a more CalDAV-like approach via links to upgrade subscriptions directly into CalDAV — used in either a server-to-server or client-to-server mode. Ultimately we will use TC-API work for the sharing protocol. The nature of invites (iCalendar or XML) still needs to be decided. We are leaning towards a more generic TC SHARING type of sharing mode.
3.10. TC IOPTEST
A busy and productive session. As always much testing of various CalDAV features. Some new implicit scheduling implementations testing against clients. Two participants were trying to get VPOLL up and running across multiple servers but ran into some implementation issues and eventually ran out of time. TC IOPTEST will start building a list of areas to test next time immediately — starting early may help to provide some specific implementation goals. Will be building this in the TESTING-NOTES etherpad. Finally we hope to have PUSH implementations for testing in January. The event report may be found at CalConnect Interoperability Test Event Reports once completed.
3.11. TC ISCHEDULE
The proposed solution to the “identity crisis” problem was presented; namely webfinger, SCHEDULE-TO-URI and SCHEDULE-ADDRESS property parameter. Lots of discussion about using SCHEDULE-ADDRESS as opposed to setting the routing address as the value of the property. Major pushback for changing the property value is that it may break existing clients which don’t understand SCHEDULE-TO-URIs. The session ended without a clear consensus. The TC will investigate how clients will handle the property value being changed. This will probably wait on IETF to start a Working Group to progress the iSchedule draft, and we will leave it as as open issue in the draft.
3.12. TC PUSH
We presented the latest output of the TC, including the new architecture, discovery of push-transports and a push protocol. There was a discussion about who defines what a topic is. Clients might want to be able to define in more detail what they are interested in. We might add that as an extension later on. Also, we briefly discussed the option to use an asynchronous call to the gateway-select URL and return an id the client can use to check if the subscription is still valid. Finally, we discussed how to proceed in the matter of the IETF webpush working group. There was consensus in that we should contact the WG and let them know about our use cases and our work.
3.13. TC RESOURCE
A presentation on the resource schema work so far was followed by a discussion of resource schemas for building management, etc. We need to look at ways to integrate or provide APIs for information relevant to the calendaring and scheduling world. Information in the structured location draft as to how to provide it so it is always available for users. The TC is now waiting on its drafts to begin progression at the IETF so will be dormant unless an issue comes up that must be addressed by the TC.
3.14. TC SHARING
This TC was formed from the Contacts Sharing Provisional Committee following CalConnect XXX. The TC presented a plan for the 4 specifications we’d like to release. There were lots of discussions around semantics and general approach, such as:
Dropping UID from xml bodies
CardDAV sharing collections. Is there only one sharee collection per sharer.
Attaching principal information to notifications.
Per-user and global properties for iCalendar. What should be the default?
Requiring vCard 4.
Sharing draft collections.
No strong decisions have been made, will have to pick those up during the post-event TC calls going forward.
3.15. TC TASKS
We discussed work done over the last few months: history/comments use cases, task assignment and VPOLL, and changes to relationships draft. We had a detailed discussion on the use of RELATED-TO, RELID/REFID, CATEGORIES. We decided we would use a URI value for REFID. We decided we needed a new property for “formal” categories. We will continue to discuss the need for an event type registry. Next up we will work on finishing the drafts, ongoing VPOLL work, and time planning.
3.16. TC TIMEZONE
No session was held at the conference. The TC is on hold pending the progression of its two drafts now adopted as TZDIST Working Group drafts in the IETF for progression to become RFCs: Time Zone Data Distribution Service and CalDAV: Timezones by Reference.
3.17. Workshop on Groups Attendees and Sharing
Reviewed proposals for server-side support. Attendees approach involved client-driven model, decided right approach was for server to make decisions on expansions. Same would apply to sharing as well. Still open questions as to how it would work, at this time decided to continue discussions within TC CALDAV once it finishes current work, and discuss again at next conference either at another workshop or as part of TC CALDAV.
3.18. Workshop on History and Comments Streams in iCalendar Data
Discussed general use cases; reached a general agreement on the need to address this in particular TC TASKS has a requirement. Approaches using external feeds through existing protocols, links to photo stream sites, etc.. The CONFERENCE property in EVENTPUB was driven by Google’s interest in a PUT to Google Hangout. Also discussed TC TASKS requirement by using VJOURNAL. Decision: we don’t have time before January to get into the topic in depth, and will return to it at the January event. In the meantime, TC TASKS will evaluate whether VJOURNAL is sufficient for its needs and the requirement can be met that way.
4. Plenary Decisions
The offer from Gershon Janssen to host the Autumn 2015 event in Amsterdam, The Netherlands was confirmed.
A Planning Committee will be formed for CalConnect’s Tenth Anniversary meeting, CalConnect XXXII, in January 2015.
5. Future Events
CalConnect XXXII: January 26-30, 2015, Kerio Technologies, San Jose, California
CalConnect XXXIII: Spring, 2015, TBD
CalConnect XXXIV: Autumn, 2015, Gershon Janssen, Amsterdam, The Netherlands
The general format of the CalConnect week is:
Monday morning through Wednesday noon, CalConnect Interoperability Test Event
Wednesday noon through Friday afternoon, CalConnect Conference (presentations, TC sessions, BOFs, networking, Plenary)
The format for European events is to move TC sessions to the afternoon and offer symposia and BOFs during Thursday and Friday mornings, and continue through Friday afternoon.
6. Pictures from CalConnect XXXI
Figure 1 — Photograph courtesy of Graham Wilson, www.grahamphotographer.co.uk
Figure 2 — The interoperability test event at The Higgins, with attendent Sarcophagus