📆 Add iCal schedule export feature (#127) (#140)

- Create schedule-ical.html template to generate .ics calendar file
- Include all talks with proper timezone handling
- Add "Add to Calendar" button to schedule page
- Calendar includes event details: time, location, presenter, description

Closes #127

Author: jefftriplett

src/schedule-ical.html

@@ -0,0 +1,59 @@
+---
+permalink: /schedule.ics
+eleventyExcludeFromCollections: true
+---
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//DjangoCon US {{ site.conf_year }}//Schedule//EN
+CALSCALE:GREGORIAN
+METHOD:PUBLISH
+X-WR-CALNAME:DjangoCon US {{ site.conf_year }}
+X-WR-TIMEZONE:{{ site.timezone }}
+X-WR-CALDESC:DjangoCon US {{ site.conf_year }} Conference Schedule
+BEGIN:VTIMEZONE
+TZID:{{ site.timezone }}
+BEGIN:DAYLIGHT
+TZOFFSETFROM:-0600
+TZOFFSETTO:-0500
+TZNAME:CDT
+DTSTART:19700308T020000
+RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:-0500
+TZOFFSETTO:-0600
+TZNAME:CST
+DTSTART:19701101T020000
+RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
+END:STANDARD
+END:VTIMEZONE
+{%- for talk in collections.talks %}
+BEGIN:VEVENT
+DTSTART;TZID={{ site.timezone }}:{{ talk.data.start_datetime | formatDateTime: "yyyyMMdd'T'HHmmss" }}
+DTEND;TZID={{ site.timezone }}:{{ talk.data.end_datetime | formatDateTime: "yyyyMMdd'T'HHmmss" }}
+DTSTAMP:{{ talk.data.start_datetime | formatDateTime: "yyyyMMdd'T'HHmmss'Z'" }}
+UID:{{ talk.fileSlug }}@{{ site.domain }}
+SUMMARY:{{ talk.data.title | replace: ",", "\," | replace: ";", "\;" | replace: "\n", " " | replace: "\r", " " }}
+{%- if talk.data.room %}
+LOCATION:{{ talk.data.room | replace: ",", "\," | replace: ";", "\;" }}
+{%- endif %}
+{%- if talk.data.presenter_slugs or talk.templateContent %}
+DESCRIPTION:
+{%- if talk.data.presenter_slugs -%}
+{%- for slug in talk.data.presenter_slugs -%}
+{%- assign presenter = collections.presenters | find: slug -%}
+{%- if presenter %}Presenter: {{ presenter.data.name }}\n{% endif -%}
+{%- endfor -%}
+{%- if talk.templateContent %}\n{% endif -%}
+{%- endif -%}
+{%- if talk.templateContent -%}
+{{ talk.templateContent | strip_html | replace: "\n", "\n " | replace: ",", "\," | replace: ";", "\;" | truncate: 1000 }}
+{%- endif %}
+{%- endif %}
+{%- if talk.data.permalink %}
+URL:{{ site.domain }}{{ talk.data.permalink }}
+{%- endif %}
+STATUS:CONFIRMED
+END:VEVENT
+{%- endfor %}
+END:VCALENDAR

src/schedule.html

@@ -23,6 +23,12 @@ <h1 class="text-center pageheading">{{ title }}</h1>
 
 <div class="pt-6 block-container">
   <div class="wrapper">
+    <div class="max-w-5xl mx-auto mb-8 text-center">
+      <a href="/schedule.ics" class="inline-flex items-center gap-2 px-6 py-3 text-lg font-medium text-white bg-teal hover:bg-teal-dark rounded-lg transition-colors" download>
+        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 7V3m8 4V3m-9 8h10M5 21h14a2 2 0 002-2V7a2 2 0 00-2-2H5a2 2 0 00-2 2v12a2 2 0 002 2z"></path></svg>
+        Add to Calendar
+      </a>
+    </div>
     <nav class="max-w-5xl mx-auto mb-12">
       <h2 class="mb-1 font-bold uppercase sr-only">Jump to day</h2>
       <ul class="flex flex-wrap justify-center gap-6">