# SilverBullet iCalendar Plug

`silverbullet-icalendar` is a [Plug](https://silverbullet.md/Plugs) for [SilverBullet](https://silverbullet.md/) which I made for my girlfriend.
It reads external [iCalendar](https://en.wikipedia.org/wiki/ICalendar) data, also known as iCal and `.ics` format, used in CalDAV protocol.

**Note**: This version (0.2.0+) is compatible with **SilverBullet v2 only**. For SilverBullet v1, use version 0.1.0.

## Installation

Run the {[Library: Install]} command and paste the following URL:
`https://github.com/Maarrk/silverbullet-icalendar/blob/main/PLUG.md`

Alternatively, you can use the older way with the {[Plugs: Add]} command:
`ghr:Maarrk/silverbullet-icalendar`

Then run the {[Plugs: Update]} command and off you go!

### Configuration

This plug is configured with [Space Config](https://silverbullet.md/Space%20Config), short example:

```yaml
icalendar:
  # where to get the iCalendar data from
  sources:
  - url: https://example.com/calendar.ics
    # this will be set as sourceName on all results from this source
    name: Example calendar
```

Instructions to get the source URL for some calendar services:

- Nextcloud ([source](https://help.nextcloud.com/t/how-to-access-the-calendar-ics-file-via-url/7880)):
  - Edit calendar (pencil icon to the right of the name)
  - Share calendar link
  - Details (three dots icon), copy subscription link
  - Verify that the link ends with `?export`
- Google Calendar ([source](https://support.google.com/calendar/answer/37648?hl=en#zippy=%2Cget-your-calendar-view-only)): 
  - Calendar settings (pencil icon to the right of the name)
  - Settings and Sharing, scroll down to Integrate calendar
  - Copy the link for Secret address in iCal format

![Screenshot of getting the URL from Nextcloud Calendar](./url-nextcloud.png)

## Usage

After configuration, run the `{[iCalendar: Sync]}` command to synchronize calendar events. The plug will cache the results for 6 hours by default (configurable via `cacheDuration` in config).

To bypass the cache and force an immediate sync, use the `{[iCalendar: Force Sync]}` command.

To completely clear all indexed events and cache (useful for troubleshooting), use the `{[iCalendar: Clear All Events]}` command.

Events are indexed with the tag `ical-event` and can be queried using Lua Integrated Query (LIQ).

### Examples

Select events that start on a given date:

~~~
```md
${query[[
  from index.tag "ical-event" 
  where start:startsWith "2024-01-04"
  select {summary=summary, description=description}
]]}
```
~~~

Get the next 5 upcoming events:
```md
${query[[
  from index.tag "ical-event"
  where start > os.date("%Y-%m-%d")
  order by start
  limit 5
]]}
```
~~~

## Roadmap

- Cache the calendar according to `REFRESH-INTERVAL` or `X-PUBLISHED-TTL`
- More indexed object types:
  - `ical-todo` for `VTODO` components
  - `ical-calendar` showing information about configured calendars
- Support `file://` URL scheme (use an external script or filesystem instead of authentication on CalDAV)

## Contributing

Pull requests with short instructions for various calendar services are welcome.
If you find bugs, report them on the [issue tracker on GitHub](https://github.com/Maarrk/silverbullet-icalendar/issues).

### Building from source

To build this plug, you need [Deno](https://deno.land/) installed. Then, build the plug with:

```shell
deno task build
```

Or to watch for changes and rebuild automatically:

```shell
deno task watch
```

The compiled plug will be written to `icalendar.plug.js`. This file is tracked by Git in this repository to allow for easy installation via the `PLUG.md` file.

## License

MIT, following SilverBullet
