Merge pull request rails#53811 from p8/guides/canonical-link

Add canonical link tag to guides head

Author: rafaelfranca

guides/rails_guides/generator.rb

@@ -186,13 +186,14 @@ def generate_guide(guide, output_file)
 
         view = ActionView::Base.with_empty_template_cache.with_view_paths(
           [@source_dir],
-          edge:         @edge,
-          version:      @version,
-          epub:         "epub/#{epub_filename}",
-          language:     @language,
-          direction:    @direction,
-          uuid:         SecureRandom.uuid,
-          digest_paths: @digest_paths
+          edge:          @edge,
+          version:       @version,
+          epub:          "epub/#{epub_filename}",
+          language:      @language,
+          direction:     @direction,
+          uuid:          SecureRandom.uuid,
+          digest_paths:  @digest_paths,
+          canonical_url: canonical_url(output_file)
         )
         view.extend(Helpers)
 
@@ -223,6 +224,12 @@ def generate_guide(guide, output_file)
         end if !dry_run?
       end
 
+      def canonical_url(path)
+        url = "https://guides.rubyonrails.org/"
+        url += path unless path == "index.html"
+        url
+      end
+
       def warn_about_broken_links(html)
         anchors = extract_anchors(html)
         check_fragment_identifiers(html, anchors)

guides/source/layout.html.erb

@@ -13,6 +13,8 @@
 
   <link rel="apple-touch-icon" href="images/icon.png">
 
+  <link rel="canonical" href="<%= @canonical %>">
+
   <script src="<%= digest_path('javascripts/@hotwired--turbo.js') %>" data-turbo-track="reload"></script>
   <script src="<%= digest_path('javascripts/clipboard.js') %>" data-turbo-track="reload"></script>
   <script src="<%= digest_path('javascripts/guides.js') %>" data-turbo-track="reload"></script>