Add calendar shortcode

README.md

@@ -47,6 +47,25 @@ For a different event than the page's section, pass its name: `{{< schedule 39c3
 
 Without a data file, or without any tours in it, the shortcode renders nothing and the build logs a warning. To silence it, for example for an upcoming event, add `warning-schedule-empty` to `ignoreLogs` in `hugo.yaml`.
 
+## Shortcode: Calendar entry
+
+`{{< calendar >}}` adds two links after a tour date: a calendar file (`.ics`) and a link that adds the date in Google Calendar. Hackertours-Admin puts it into the list of dates on each tour page:
+
+```markdown
+* Tag 1 (27.12.) **17:30 Uhr** {{< calendar date="2026-12-27" time="17:30" duration="210" >}}
+```
+
+| Param | Required | Content |
+|---|---|---|
+| `date` | yes | `YYYY-MM-DD` |
+| `time` | yes | Start time `HH:MM`, local time in Hamburg |
+| `duration` | no | Length in minutes. Without it, `duration` of the tour in `tours` in the schedule file is used (see "Map data in the schedule file"); without either, the calendar entry has no end time and the build logs a warning with the ID `warning-calendar-duration`. |
+| `title` | no | Title of the calendar entry. Without it, the `title` of this date in the schedule file is used, then the page title. |
+
+The `.ics` file is in the iCalendar format (RFC 5545), which Apple Calendar, Outlook, Thunderbird and most other calendar apps open directly, as does Google Calendar when importing a file. The extra Google Calendar link is there because the Google Calendar app on Android doesn't open downloaded `.ics` files.
+
+Each entry starts at the time given, in Hamburg time, at the Hackertours desk (with `map.origin` from the schedule file as the address, if there is one). Its description is the tour summary and a link to the tour page. The files are generated next to the tour page, one per date and language, e.g. `/de/40c3/tour-of-the-giants/tour-of-the-giants-2026-12-27-1730.ics`.
+
 ## Shortcode: Tour map
 
 `{{< tour-map >}}` on an event's overview page shows a map of the tour locations, with the routes from the Congress, on OpenStreetMap. For a different event than the page's section, pass its name: `{{< tour-map 39c3 >}}`. It uses [Leaflet](https://leafletjs.com), which is kept in [assets/vendor/leaflet/](assets/vendor/leaflet/).
@@ -101,6 +120,7 @@ days:
 | `icon` | no | Name of an icon for the marker, see "Map icons" below. Without it, or with an unknown name, the marker is a plain coloured circle; an unknown name also logs a build warning. |
 | `directions` | no | How to get there from the origin, per language (`de`, `en`) as Markdown, usually a short list of steps. |
 | `route` | no | The way from `map.origin` to `geo` as a list of legs in travel order. Without it the tour only gets a marker. |
+| `duration` | no | Length of the tour in minutes, used by the calendar entries when the `calendar` shortcode doesn't pass one. |
 
 Each leg in `route` has:
 

assets/css/_custom.css

@@ -106,3 +106,11 @@ span.content-image {
   font-size: var(--fs-xs);
   color: var(--color-text-meta);
 }
+
+/* Calendar links after a tour date, see layouts/_shortcodes/calendar.html. */
+.tour-calendar {
+  margin-inline-start: 0.5em;
+  font-family: var(--ff-alt);
+  font-size: var(--fs-s);
+  white-space: nowrap;
+}

i18n/de.yaml

@@ -5,3 +5,6 @@ tour_map_osm: "auf OpenStreetMap"
 skip_to_content: "Zum Inhalt springen"
 logo_alt: "Hamburg Hackertours – Startseite"
 map_39c3_title: "Karte der 39C3-Touren mit Wegen vom CCH (uMap)"
+calendar_meeting_point: "Hackertours-Desk"
+calendar_ics: "Kalendereintrag (.ics)"
+calendar_google: "Google Kalender"

i18n/en.yaml

@@ -5,3 +5,6 @@ tour_map_osm: "on OpenStreetMap"
 skip_to_content: "Skip to content"
 logo_alt: "Hamburg Hackertours – home page"
 map_39c3_title: "Map of the 39C3 tours with routes from the CCH (uMap)"
+calendar_meeting_point: "Hackertours Desk"
+calendar_ics: "Calendar entry (.ics)"
+calendar_google: "Google Calendar"

layouts/_partials/ics-line.html

@@ -0,0 +1,22 @@
+{{- /*
+One iCalendar (RFC 5545) content line: "NAME:value" plus CRLF, folded so that no line is
+longer than 75 bytes (continuation lines start with a space). Params: name, value, text
+(true to escape the value as TEXT: backslash, semicolon, comma and newlines).
+*/ -}}
+{{- $value := .value | default "" -}}
+{{- if .text -}}
+  {{- $value = $value | replaceRE `\\` `\\` | replaceRE `;` `\;` | replaceRE `,` `\,` | replaceRE `\r?\n` `\n` -}}
+{{- end -}}
+{{- $out := "" -}}
+{{- $line := "" -}}
+{{- $bytes := 0 -}}
+{{- range split (printf "%s:%s" .name $value) "" -}}
+  {{- if gt (add $bytes (len .)) 75 -}}
+    {{- $out = printf "%s%s\r\n " $out $line -}}
+    {{- $line = "" -}}
+    {{- $bytes = 1 -}}
+  {{- end -}}
+  {{- $line = printf "%s%s" $line . -}}
+  {{- $bytes = add $bytes (len .) -}}
+{{- end -}}
+{{- return printf "%s%s\r\n" $out $line -}}

layouts/_shortcodes/calendar.html

@@ -0,0 +1,84 @@
+{{- /*
+Calendar links for one date of a tour: an .ics file (iCalendar, for Apple Calendar, Outlook,
+Thunderbird and most other apps) and a link that adds the event in Google Calendar.
+Meant for the list of dates on a tour page:
+
+  * Tag 1 (27.12.) **17:30 Uhr** {{< calendar date="2026-12-27" time="17:30" duration="210" >}}
+
+Params: date (YYYY-MM-DD), time (HH:MM, local time in Hamburg), duration in minutes
+(optional, else tours.<slug>.duration in data/schedule/<event>.yaml), title (optional, else the
+title of this date in the schedule data, else the page title).
+*/ -}}
+{{- $page := .Page -}}
+{{- $lang := $page.Language.Name -}}
+{{- $other := cond (eq $lang "de") "en" "de" -}}
+{{- $event := $page.Section -}}
+{{- $slug := $page.File.ContentBaseName -}}
+{{- $date := .Get "date" -}}
+{{- $time := .Get "time" -}}
+{{- if not (and (findRE `^\d{4}-\d{2}-\d{2}$` $date) (findRE `^\d{2}:\d{2}$` $time)) -}}
+  {{- errorf "calendar: date must be YYYY-MM-DD and time HH:MM, got %q %q: %s" $date $time .Position -}}
+{{- end -}}
+
+{{- $data := dict -}}
+{{- with hugo.Data.schedule }}{{ with index . $event }}{{ $data = . }}{{ end }}{{ end -}}
+{{- $tourData := dict -}}
+{{- with $data.tours }}{{ with index . $slug }}{{ $tourData = . }}{{ end }}{{ end -}}
+{{- /* This date in the schedule, for its title. */ -}}
+{{- $slot := dict -}}
+{{- range $data.days -}}
+  {{- if eq .date $date -}}
+    {{- range .tours }}{{ if and (eq .tour $slug) (eq .time $time) }}{{ $slot = . }}{{ end }}{{ end -}}
+  {{- end -}}
+{{- end -}}
+
+{{- $title := .Get "title" -}}
+{{- if not $title }}{{ with $slot.title }}{{ $title = index . $lang | default (index . $other) }}{{ end }}{{ end -}}
+{{- $title = $title | default $page.Title -}}
+
+{{- $minutes := int (.Get "duration" | default ($tourData.duration | default 0)) -}}
+{{- if not $minutes -}}
+  {{- warnidf "warning-calendar-duration" "calendar: no duration for %s on %s %s, the calendar entry has no end time: %s" $slug $date $time .Position -}}
+{{- end -}}
+
+{{- $start := time.AsTime (printf "%sT%s:00" $date $time) "Europe/Berlin" -}}
+{{- $end := $start.Add (time.ParseDuration (printf "%dm" $minutes)) -}}
+{{- $utc := "20060102T150405Z" -}}
+
+{{- /* Everyone meets at the Hackertours desk, which is where the routes on the map start. */ -}}
+{{- $location := i18n "calendar_meeting_point" -}}
+{{- with $data.map }}{{ with .origin }}{{ with .name -}}
+  {{- $location = printf "%s, %s" $location (index . $lang | default (index . $other)) -}}
+{{- end }}{{ end }}{{ end -}}
+{{- /* The front matter summary: .Summary would render this page again from inside its own shortcode. */ -}}
+{{- $summary := $page.Params.summary | default $page.Description | default "" -}}
+{{- $description := printf "%s\n\n%s" ($page.RenderString $summary | plainify | htmlUnescape | strings.TrimSpace) $page.Permalink -}}
+
+{{- $ics := printf "BEGIN:VCALENDAR\r\nVERSION:2.0\r\nPRODID:-//CCC Hansestadt Hamburg//Hackertours//%s\r\nCALSCALE:GREGORIAN\r\nMETHOD:PUBLISH\r\nBEGIN:VEVENT\r\n" (upper $lang) -}}
+{{- $ics = printf "%s%s" $ics (partial "ics-line.html" (dict "name" "UID" "value" (printf "%s-%s-%s-%s@%s" $event $slug $date (replace $time ":" "") (urls.Parse site.BaseURL).Host))) -}}
+{{- $ics = printf "%s%s" $ics (partial "ics-line.html" (dict "name" "DTSTAMP" "value" ($page.Lastmod.UTC.Format $utc))) -}}
+{{- $ics = printf "%s%s" $ics (partial "ics-line.html" (dict "name" "DTSTART" "value" ($start.UTC.Format $utc))) -}}
+{{- if $minutes }}{{ $ics = printf "%s%s" $ics (partial "ics-line.html" (dict "name" "DTEND" "value" ($end.UTC.Format $utc))) }}{{ end -}}
+{{- $ics = printf "%s%s" $ics (partial "ics-line.html" (dict "name" "SUMMARY" "value" $title "text" true)) -}}
+{{- $ics = printf "%s%s" $ics (partial "ics-line.html" (dict "name" "LOCATION" "value" $location "text" true)) -}}
+{{- with $data.map }}{{ with .origin }}{{ with .geo -}}
+  {{- $ics = printf "%s%s" $ics (partial "ics-line.html" (dict "name" "GEO" "value" (printf "%v;%v" .lat .lon))) -}}
+{{- end }}{{ end }}{{ end -}}
+{{- $ics = printf "%s%s" $ics (partial "ics-line.html" (dict "name" "DESCRIPTION" "value" $description "text" true)) -}}
+{{- $ics = printf "%s%s" $ics (partial "ics-line.html" (dict "name" "URL" "value" $page.Permalink)) -}}
+{{- $ics = printf "%sEND:VEVENT\r\nEND:VCALENDAR\r\n" $ics -}}
+
+{{- $file := printf "%s-%s-%s.ics" $slug $date (replace $time ":" "") -}}
+{{- $icsFile := resources.FromString (path.Join (strings.TrimPrefix "/" $page.RelPermalink) $file) $ics -}}
+{{- $google := printf "https://calendar.google.com/calendar/render?%s" (querify
+  "action" "TEMPLATE"
+  "text" $title
+  "dates" (printf "%s/%s" ($start.UTC.Format $utc) ($end.UTC.Format $utc))
+  "details" $description
+  "location" $location
+  "ctz" "Europe/Berlin"
+) -}}
+{{- /* The visible link texts repeat for every date; the hidden part says which date it is. */ -}}
+{{- $when := printf "%s %s" ($start | time.Format "Mon 2.1.") $time -}}
+<span class="tour-calendar"><a href="{{ $icsFile.RelPermalink }}" download="{{ $file }}">{{ i18n "calendar_ics" }}<span class="visually-hidden"> {{ $when }}</span></a> · <a href="{{ $google }}">{{ i18n "calendar_google" }}<span class="visually-hidden"> {{ $when }}</span></a></span>
+{{- /* chomp */ -}}