Export an icalendar file from a listing search

[stevepiercy]

Is your feature request related to a problem? Please describe.

After resolving #226, we now have the ability to download a single event's icalendar file.

The next step would be to export a single icalendar file of a collection of events. Examples of collections include:

• Future events only
• Future sprint events
• Future Volto Team events EDIT: open to Volto Team members only due to disruptive GSoC aspirants crashing the event and asking for technical support. This collection is not needed.
• Future events with a virtual or remote participation component

Such a collection would have its own unique URL to download the icalendar file. This would allow visitors to import a complete icalendar file into their personal calendar applications.

Describe the solution you'd like

@acsr put together a proof of concept that does that.

• https://tagung.plone.de/2025/tagung/programm-plone-tagung/event-collection/ics_view
• https://tagung.plone.de/2025/tagung/programm-plone-tagung/event-collection/

The steps included the following.

• Go to Classic UI and enable Collections as implicitly addable in ZMI portal types.
• Make sure you can add a Collection and configure it to collect what you need.
• Append /ics_view to the regular, non-Classic UI URL, and you get an iCalendar file with all events.
• If you ask yourself why reccuring events are not explicitly listed as separate events, read this: Don't include occurrences in ical exports of containers and event_listing plone.app.event#103
• Fun Fact: You can still use the configurable Table view to export the list as CSV.

Describe alternatives you've considered

Another option would be to allow users to first search for events, then export the search results into a single or individual icalendar files, but I don't think there's much demand for this use case.

Additional context

This idea came about from the relaunch of Open Tech Calendar, a demo of Open Web Calendar, and @stevepiercy's ongoing documentation project on icalendar.

Further discussion took place in Discord in the ploneorg-marketing Discord channel discussion.

This issue description may be revised, depending on further comments, including the steps that Armin took to make the demo successful.

[acsr]

I could reproduce this on https://tagung.plone.de/2025/tagung/programm-plone-tagung/event-collection/ics_view

it seems to be a good idea to set the view layout of the collection to tabularview from the classic UI or otherwise it looks messy in VLT.

The nice thing is that youn can configure the tabular view fields without affecting the iCal export.
To tweak the iCal Export you need to customize plone.app.event.ical.exporter or whatever is responisble to build the export today.
(older) docs are at:

• https://ploneappevent.readthedocs.io/en/latest/api/ical/exporter.html
• https://5.docs.plone.org/_modules/plone/app/event/ical/exporter.html

I am not into the details current state of the iCal export from Volto. I just contributed this approach as a workaround.

The actual collection in tabular view looks in Volto like this:

https://tagung.plone.de/2025/tagung/programm-plone-tagung/event-collection

This needs some CSS love (for the collection view) to fence that into the usual VLT layout, but that s something I could only fix later.

After adding the collection that way, you can safely remove the implicitly addable checkbox in ZMI/portal_types (ClassicUI/portal_types/Collection/manage_propertiesForm) to avoid unintended adding of collections, if you keep the Volto VLT way.

NOTE: The Rich Text content you add in Classic is not visible in Volto unless you change more. The iCal Download Link therefore cannot be substituted. Only the html table is rendered as content inside the Volto site (useful for other tasks, using )

[jarofgreen]

Hello, James from Open Tech Calendar here.

I've added World Plone Day for now by just importing the ICAL for one event only - https://opentechcalendar.co.uk/group/plone

When there's a collection of future events I'll switch to that. So partly commenting so I'm watching the issue and get updates.

I'm hoping the UID field for each event will be consistent, whether it's in a individual event URL or a collection URL. That will be important for people tracking the data and wanting to be clear whether it's a new event or an update to an existing event.

Also as we list virtual or hybrid events but not in-person only events, I'm looking for a way to filter for that - I see for World Plone Day the LOCATION field has the word "Online" in, if that's always true I can use that, or maybe there could be a special collection?

Thanks for working on a good open data feed!
James

[acsr]

@jarofgreen wrote:

UID field for each event will be consistent, whether it's in a individual event URL or a collection URL. That will be important for people tracking the data and wanting to be clear whether it's a new event or an update to an existing event.

Thanks for pointing that out here. I absolutely agree. I am not involved in the final process for now, but writing down the full lifecycle User Service Blueprint as a Swimlane Diagram is one of my internal tasks and goes much further than just publishing the iCal files. When I finish to publish my wrapup, this is maybe also useful for you. Great Work!

[erral]

@stevepiercy I have created the following Collection in Classic UI interface:

• Future events only: https://plone.org/++api++/news-and-events/events/collection/ics_view
• Future sprint events: https://plone.org/++api++/news-and-events/events/collection-sprints/ics_view

If that's OK, we can edit the Events page and create links to such icalendar files.

Do we have any listing of "Future Volto Team Events"? If so point me to that please and I will create the collection

[stevepiercy]

@erral sorry for the delay. These look great! Please go ahead and edit the Events page.

I'll ask at the next Volto Team meeting how they want to be listed, if at all. We had to go to invitation only because of the GSoC aspirants crashing the meeting asking for support. IOW, if you know, you know.

@jarofgreen the future events only URL (https://plone.org/++api++/news-and-events/events/collection/ics_view) is ready for Open Tech Calendar. Please let me know if you need anything further from us. Thank you!

[stevepiercy]

The Volto Team meetings are for Volto Team members only and it's private, so we don't want to publish it on plone.org. However, we'll update the page with current information.