Add support for previewing publishable articles on home page

Author: rossta

app/content/models/article_page.rb

@@ -7,17 +7,20 @@ class ArticlePage < Sitepress::Model
 
   delegate :mime_type, :handler, to: :page
 
-  def self.published
-    all.filter(&:published?)
+  def self.published(params = {})
+    all
+      .filter { |article| article.published?(preview: params[:preview]) }
       .sort { |a, b| b.published_on <=> a.published_on } # DESC order
   end
 
   def self.draft
     all.filter(&:draft?)
   end
 
-  def published?
-    published_on.presence && published_on <= Date.today
+  # Consider an article published if it has a published date prior to today.
+  # If preview is true, consider the article published regardless of the date.
+  def published?(preview: false)
+    published_on.presence && (preview || published_on <= Date.today)
   end
 
   def draft? = !published?

app/content/pages/index.html.erb

@@ -4,7 +4,7 @@ title: Joy of Rails
 
 <section style="min-height: 51vh">
   <div class="main-content container py-gap lg:py-3xl">
-    <% ArticlePage.published.take(4).zip(%w[left right].cycle).each do |(page, side)| %>
+    <% ArticlePage.published(params).take(4).zip(%w[left right].cycle).each do |(page, side)| %>
       <%= render Pages::Summary.from_page(page, side: side) %>
     <% end %>
   </div>

spec/requests/site/articles_spec.rb

@@ -6,6 +6,20 @@
   # Filter out index.html.erb from article pages before selecting first draft
   let(:first_draft) { ArticlePage.draft.lazy.filter { |article| article.page.request_path != "/articles" }.first }
 
+  describe "GET /" do
+    it "lists recent published articles" do
+      get "/"
+
+      expect(response).to have_http_status(:ok)
+    end
+
+    it "supports preview flag" do
+      get "/", params: {preview: true}
+
+      expect(response).to have_http_status(:ok)
+    end
+  end
+
   describe "GET /articles" do
     it "lists published articles" do
       get "/articles"