RSSフィード作成

Gemfile

@@ -37,6 +37,9 @@ gem 'rack-attack'
 gem 'google_drive'
 gem 'lazy_high_charts'
 
+# For RSS feed
+gem 'ruby-mp3info', :require => 'mp3info'
+
 group :development do
   gem 'web-console'
   gem 'spring'

Gemfile.lock

@@ -285,6 +285,7 @@ GEM
     rspec-retry (0.6.1)
       rspec-core (> 3.3)
     rspec-support (3.8.0)
+    ruby-mp3info (0.8.10)
     ruby_dep (1.5.0)
     ruby_parser (3.12.0)
       sexp_processor (~> 4.9)
@@ -428,6 +429,7 @@ DEPENDENCIES
   rake
   rspec-rails (~> 3.5)
   rspec-retry
+  ruby-mp3info
   sass-rails
   scrivito (~> 1.15.0)
   scrivito_section_widgets

app/controllers/podcasts_controller.rb

@@ -14,4 +14,15 @@ def show
     @content  = Kramdown::Document.new(@episode.content, input: 'GFM').to_html
     @url      = request.url
   end
+
+  def feed
+    @episodes     = Podcast.all.sort_by{|episode| episode.published_at}
+    @base_url     = request.base_url
+    @author       = "一般社団法人 CoderDojo Japan"
+    @art_work_url = "https://coderdojo.jp/podcasts/cover.jpg"
+    @current_year = Time.current.year
+    respond_to do |format|
+      format.rss { render :layout => false }
+    end
+  end
 end

app/models/podcast.rb

@@ -28,6 +28,20 @@ def exists?(offset: 0)
     File.exists?("#{DIR_PATH}/#{self.filename.to_i + offset}.md")
   end
 
+  def filesize
+    @size ||= File.size("#{DIR_PATH}/#{self.filename}.mp3")
+  end
+
+  def duration
+    return @duration if @duration
+
+    path = "#{DIR_PATH}/#{self.filename}.mp3"
+    open_opts = { :encoding => 'utf-8' }
+    Mp3Info.open(path, open_opts) do |mp3info|
+      @duration = Time.at(mp3info.length).utc.strftime('%H:%M:%S')
+    end
+  end
+
   def title
     @title ||= exists? ? self.content.lines.first[2..-1].strip.gsub('<br>', '') : ''
   end
@@ -36,6 +50,10 @@ def description
     @desc  ||= exists? ? self.content.lines.reject{|l| l =~ /^(\n|<)/ }.second.delete('<br>').strip : ''
   end
 
+  def published_at
+    @published_at ||= exists? ? Time.parse(self.content.lines.second.gsub(/<.+?>/, '').delete('収録日: ')) : ''
+  end
+
   def content
     @content ||= exists? ? File.read(path) : ''
   end

app/views/podcasts/feed.rss.builder

@@ -0,0 +1,36 @@
+xml.instruct! :xml, :version => "1.0"
+xml.rss :version => "2.0", "xmlns:itunes" => "http://www.itunes.com/dtds/Podcast-1.0.dtd" do
+  xml.channel do
+    xml.title       full_title ""
+    xml.description full_description ""
+    xml.link        root_url
+    xml.image       @art_work_url
+    xml.author      @author
+    xml.copyright   "Copyright © 2012-#{@current_year} #{@author}"
+    xml.language    "ja"
+    xml.itunes :category, :text => "Technology" do
+      xml.itunes :category, :text => "Software How-To"
+      xml.itunes :category, :text => "Podcasting"
+    end
+    xml.itunes :type,     "serial"
+    xml.itunes :explicit, "clean"
+
+    @episodes.each do |episode|
+      xml.item do
+        xml.title        episode.title
+        xml.author       @author
+        xml.description  episode.description
+        xml.link         "#{@base_url}#{episode.url}"
+        xml.guid({:isPermaLink => "false"}, "#{@base_url}#{episode.url}")
+        xml.itunes       :explicit, "clean"
+        xml.published_at episode.published_at.rfc2822
+        xml.enclosure({
+	  :url    => "#{@base_url}#{episode.url}.mp3",
+	  :length => episode.filesize,
+	  :type   => "audio/mpeg"}
+	)
+        xml.itunes       :duration, episode.duration
+      end
+    end
+  end
+end

config/routes.rb

@@ -11,6 +11,7 @@
   get "/docs/charter_en",       to: redirect('/charter_en')
   get "/docs/financial-report", to: redirect('/financial-report')
   get "/login",                 to: redirect('/login-8717e64efaf19d7d')
+  get "/podcasts/feed"    => "podcasts#feed"
   get "/charter"          => "docs#show", id: 'charter'
   get "/charter_en"       => "docs#show", id: 'charter_en'
   get "/financial-report" => "docs#show", id: 'financial-report'