fix: timezones in ical

Author: JesperDramsch

Gemfile

@@ -18,3 +18,7 @@ gem "jekyll-include-cache", "~> 0.2.1"
 gem "execjs", "~> 2.9"
 
 gem "nokogiri", "~> 1.16"
+
+gem "tzinfo", "~> 2.0"
+
+gem "tzinfo-data", "~> 1.2024"

Gemfile.lock

@@ -95,6 +95,10 @@ GEM
       google-protobuf (>= 3.25, < 5.0)
     terminal-table (3.0.2)
       unicode-display_width (>= 1.1.1, < 3)
+    tzinfo (2.0.6)
+      concurrent-ruby (~> 1.0)
+    tzinfo-data (1.2024.2)
+      tzinfo (>= 1.0.0)
     unicode-display_width (2.5.0)
     webrick (1.8.2)
 
@@ -114,6 +118,8 @@ DEPENDENCIES
   jekyll-sitemap
   kramdown-parser-gfm
   nokogiri (~> 1.16)
+  tzinfo (~> 2.0)
+  tzinfo-data (~> 1.2024)
   webrick (~> 1.8)
 
 BUNDLED WITH

_layouts/calendar-deadlines.ics

@@ -10,7 +10,8 @@ DTSTART:19700101T000000Z
 TZOFFSETFROM:+0000
 TZOFFSETTO:+0000
 END:STANDARD
-END:VTIMEZONE{% for conf in site.data.conferences %}
+END:VTIMEZONE
+{% for conf in site.data.conferences %}
 {%- if conf.cfp_ext -%}
     {%- assign cfp = conf.cfp_ext -%}
     {%- assign extended = "(extended)" -%}
@@ -19,34 +20,34 @@ END:VTIMEZONE{% for conf in site.data.conferences %}
     {%- assign extended = "" -%}
 {%- endif -%}
 {%- capture desc -%}<a href="{{conf.link}}">{{ conf.conference }} {{ conf.year }}</a> found on <a href="https://pythondeadlin.es">PythonDeadlin.es</a>.{%- endcapture -%}
-{% if conf.workshop_deadline and conf.workshop_deadline != "TBA" %}
+{%- if conf.workshop_deadline and conf.workshop_deadline != "TBA" -%}
 BEGIN:VEVENT
 SUMMARY:{{ conf.conference }} {{ conf.year }} Workshop Deadline
 UID:{{ conf.conference | slugify: "latin" }}-{{ conf.year }}[email protected]
 DTSTAMP:{{ site.time | date: "%Y%m%dT%H%M%SZ" }}
-DTSTART:{{ conf.workshop_deadline | date: "%Y%m%dT%H%M%SZ" }}
+DTSTART:{{ conf.workshop_deadline | to_utc: conf.timezone }}
 {{ desc | prepend: "DESCRIPTION:" | normalize_whitespace | wrap_lines }}
 ORGANIZER;CN=PythonDeadlines:mailto:[email protected]
 END:VEVENT
-{% endif %}
-{% if conf.tutorial_deadline and conf.tutorial_deadline != "TBA" %}
+{%- endif -%}
+{%- if conf.tutorial_deadline and conf.tutorial_deadline != "TBA" -%}
 BEGIN:VEVENT
 SUMMARY:{{ conf.conference }} {{ conf.year }} Tutorial Deadline
 UID:{{ conf.conference | slugify: "latin" }}-{{ conf.year }}[email protected]
 DTSTAMP:{{ site.time | date: "%Y%m%dT%H%M%SZ" }}
-DTSTART:{{ conf.tutorial_deadline | date: "%Y%m%dT%H%M%SZ" }}
+DTSTART:{{ conf.tutorial_deadline | to_utc: conf.timezone }}
 {{ desc | prepend: "DESCRIPTION:" | normalize_whitespace | wrap_lines }}
 ORGANIZER;CN=PythonDeadlines:mailto:[email protected]
 END:VEVENT
-{% endif %}
-{% if cfp != "TBA" and cfp != "None" and cfp != "Cancelled" %}
+{%- endif -%}
+{%- if cfp != "TBA" and cfp != "None" and cfp != "Cancelled" -%}
 BEGIN:VEVENT
 SUMMARY:{{ conf.conference }} {{ conf.year }} Deadline {{ extended }}
 UID:{{ conf.conference | slugify: "latin" }}-{{ conf.year }}@pythondeadlin.es
 DTSTAMP:{{ site.time | date: "%Y%m%dT%H%M%SZ" }}
-DTSTART:{{ cfp | date: "%Y%m%dT%H%M%SZ" }}
+DTSTART:{{ cfp | to_utc: conf.timezone }}
 {{ desc | prepend: "DESCRIPTION:" | normalize_whitespace | wrap_lines }}
 ORGANIZER;CN=PythonDeadlines:mailto:[email protected]
 END:VEVENT
-{% endif %}{% endfor %}
+{%- endif -%}{% endfor %}
 END:VCALENDAR

_plugins/jekyll-timezone-finder.rb

@@ -0,0 +1,33 @@
+# _plugins/timezone_filters.rb
+require 'tzinfo'
+
+module Jekyll
+  module TimezoneFilters
+    def to_utc(date, timezone = "Etc/GMT+12")
+      return nil if date.nil? || date == "TBA" || date == "None" || date == "Cancelled"
+
+      date = Time.parse(date.to_s) unless date.is_a?(Time)
+
+      begin
+        if timezone&.start_with?("UTC")
+          offset = timezone[3..-1].to_i
+          offset_seconds = offset * 3600
+          time_with_offset = Time.at(date.to_i - offset_seconds).utc
+          time_with_offset.strftime("%Y%m%dT%H%M%SZ")
+        else
+          tz = TZInfo::Timezone.get(timezone)
+          local = tz.local_datetime(date.year, date.month, date.day, date.hour, date.min, date.sec)
+          utc = tz.local_to_utc(local)
+          utc.strftime("%Y%m%dT%H%M%SZ")
+        end
+      rescue TZInfo::InvalidTimezoneIdentifier
+        tz = TZInfo::Timezone.get("Etc/GMT+12")
+        local = tz.local_datetime(date.year, date.month, date.day, date.hour, date.min, date.sec)
+        utc = tz.local_to_utc(local)
+        utc.strftime("%Y%m%dT%H%M%SZ")
+      end
+    end
+  end
+end
+
+Liquid::Template.register_filter(Jekyll::TimezoneFilters)