Google Calendarで公開されている日本の祝日のiCal形式のファイルを読み込んで取得する。

事前準備

icalendar の gem をインストールするか、Gemfileに追加して bundle install する。

gem install icalendar

日本の祝日データを取得

require 'net/http'
require 'icalendar'
holiday_ical = Net::HTTP.get(URI::parse("https://calendar.google.com/calendar/ical/ja.japanese%23holiday%40group.v.calendar.google.com/public/basic.ics")).force_encoding("UTF-8")
cals = Icalendar.parse(holiday_ical)
events = cals.first.events

以下の形で現在日周辺の祝日名と祝日の日付を取得できる。

events.map{|e| [e.dtstart, e.summary]}
=> [[Mon, 23 Sep 2024, "秋分の日 振替休日"], [Sun, 22 Sep 2024, "秋分の日"], 
[Sat, 23 Sep 2023, "秋分の日"], [Mon, 15 Jul 2024, "海の日"], 
[Mon, 17 Jul 2023, "海の日"], [Mon, 29 Apr 2024, "昭和の日"],
[Sat, 29 Apr 2023, "昭和の日"], [Wed, 20 Mar 2024, "春分の日"], 
[Tue, 21 Mar 2023, "春分の日"], [Mon, 04 Nov 2024, "文化の日 振替休日"], 
[Sun, 03 Nov 2024, "文化の日"], [Fri, 03 Nov 2023, "文化の日"],
[Thu, 03 Nov 2022, "文化の日"], [Mon, 16 Sep 2024, "敬老の日"], 
[Mon, 18 Sep 2023, "敬老の日"], [Mon, 08 Jan 2024, "成人の日"], 
[Mon, 09 Jan 2023, "成人の日"], [Fri, 03 May 2024, "憲法記念日"], 
[Wed, 03 May 2023, "憲法記念日"], [Mon, 12 Feb 2024, "建国記念の日 振替休日"],
[Sun, 11 Feb 2024, "建国記念の日"], [Sat, 11 Feb 2023, "建国記念の日"],
[Sun, 11 Aug 2024, "山の日"], [Fri, 11 Aug 2023, "山の日"], 
[Fri, 23 Feb 2024, "天皇誕生日"], [Thu, 23 Feb 2023, "天皇誕生日"],
[Sat, 23 Nov 2024, "勤労感謝の日"], [Thu, 23 Nov 2023, "勤労感謝の日"], 
[Wed, 23 Nov 2022, "勤労感謝の日"], [Mon, 01 Jan 2024, "元日"],
[Sun, 01 Jan 2023, "元日"], [Mon, 12 Aug 2024, "休日 山の日"],
[Mon, 02 Jan 2023, "休日 元日"], [Mon, 14 Oct 2024, "スポーツの日"],
[Mon, 09 Oct 2023, "スポーツの日"], [Mon, 10 Oct 2022, "スポーツの日"],
[Sat, 04 May 2024, "みどりの日"], [Thu, 04 May 2023, "みどりの日"], 
[Mon, 06 May 2024, "こどもの日 振替休日"], [Sun, 05 May 2024, "こどもの日"],
[Fri, 05 May 2023, "こどもの日"], [Mon, 19 Sep 2022, "敬老の 日"], 
[Wed, 23 Feb 2022, "天皇誕生日"], [Wed, 04 May 2022, "みどりの日"], 
[Fri, 23 Sep 2022, "秋分の日"], [Fri, 11 Feb 2022, "建国記念の日"], 
[Thu, 11 Aug 2022, "山の日"], [Sat, 01 Jan 2022, "元日"], 
[Thu, 05 May 2022, "こどもの日"], [Fri, 29 Apr 2022, "昭和の日"], 
[Mon, 21 Mar 2022, "春分の日"], [Mon, 10 Jan 2022, "成人の日"],
[Mon, 18 Jul 2022, "海の日"], [Tue, 03 May 2022, "憲法記念日"]]