Install ActionText

Add JS/CSS to the admin layout only.

To prevent deprecation warnings we set the following as this will be the
default in Rails 7.1:
  `config.active_storage.replace_on_assign_to_many = true`

app/assets/stylesheets/actiontext.css

@@ -0,0 +1,31 @@
+/*
+ * Provides a drop-in pointer for the default Trix stylesheet that will format the toolbar and
+ * the trix-editor content (whether displayed or under editing). Feel free to incorporate this
+ * inclusion directly in any other asset bundle and remove this file.
+ *
+ *= require trix
+*/
+
+/*
+ * We need to override trix.css’s image gallery styles to accommodate the
+ * <action-text-attachment> element we wrap around attachments. Otherwise,
+ * images in galleries will be squished by the max-width: 33%; rule.
+*/
+.trix-content .attachment-gallery > action-text-attachment,
+.trix-content .attachment-gallery > .attachment {
+  flex: 1 0 33%;
+  padding: 0 0.5em;
+  max-width: 33%;
+}
+
+.trix-content .attachment-gallery.attachment-gallery--2 > action-text-attachment,
+.trix-content .attachment-gallery.attachment-gallery--2 > .attachment, .trix-content .attachment-gallery.attachment-gallery--4 > action-text-attachment,
+.trix-content .attachment-gallery.attachment-gallery--4 > .attachment {
+  flex-basis: 50%;
+  max-width: 50%;
+}
+
+.trix-content action-text-attachment .attachment {
+  padding: 0 !important;
+  max-width: 100% !important;
+}

app/assets/stylesheets/admin.scss

@@ -1,3 +1,5 @@
+//= require "actiontext"
+
 /* As we're namespacing bootstrap to class admin, which is applied to the body
 element in the admin interface (no id or class allowed on the HTML element
 in HTML 4.01) and to the navbar also, so it can be styled with bootstrap

app/views/active_storage/blobs/_blob.html.erb

@@ -0,0 +1,14 @@
+<figure class="attachment attachment--<%= blob.representable? ? "preview" : "file" %> attachment--<%= blob.filename.extension %>">
+  <% if blob.representable? %>
+    <%= image_tag blob.representation(resize_to_limit: local_assigns[:in_gallery] ? [ 800, 600 ] : [ 1024, 768 ]) %>
+  <% end %>
+
+  <figcaption class="attachment__caption">
+    <% if caption = blob.try(:caption) %>
+      <%= caption %>
+    <% else %>
+      <span class="attachment__name"><%= blob.filename %></span>
+      <span class="attachment__size"><%= number_to_human_size blob.byte_size %></span>
+    <% end %>
+  </figcaption>
+</figure>

app/views/layouts/action_text/contents/_content.html.erb

@@ -0,0 +1,3 @@
+<div class="trix-content">
+  <%= yield -%>
+</div>

app/views/layouts/admin.html.erb

@@ -11,6 +11,9 @@
     <%= javascript_include_tag "admin" %>
     <%= stylesheet_link_tag "admin", :title => "Main", :rel => "stylesheet" %>
     <%= stylesheet_link_tag 'admin/print', :rel => "stylesheet", :media => "print"  %>
+
+    <script type="text/javascript" src="https://unpkg.com/trix@2.0.8/dist/trix.umd.min.js"></script>
+
     <%= render :partial => 'layouts/favicon' %>
 
   </head>

config/application.rb

@@ -9,7 +9,7 @@
 require "action_controller/railtie"
 require "action_mailer/railtie"
 # require "action_mailbox/engine"
-# require "action_text/engine"
+require "action_text/engine"
 require "action_view/railtie"
 # require "action_cable/engine"
 require "sprockets/railtie"
@@ -34,6 +34,7 @@ class Application < Rails::Application
     config.autoloader = :zeitwerk
     config.active_record.legacy_connection_handling = false
     config.active_support.use_rfc4122_namespaced_uuids = true
+    config.active_storage.replace_on_assign_to_many = true
 
     # The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
     # config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]

db/migrate/20240228122324_create_action_text_tables.action_text.rb

@@ -0,0 +1,29 @@
+# This migration comes from action_text (originally 20180528164100)
+class CreateActionTextTables < ActiveRecord::Migration[6.0]
+  def change
+    # Use Active Record's configured type for primary and foreign keys
+    primary_key_type, foreign_key_type = primary_and_foreign_key_types
+
+    create_table :action_text_rich_texts, id: primary_key_type do |t|
+      t.string     :name, null: false
+      t.text       :body, size: :long
+      t.references :record,
+        null: false, polymorphic: true, index: false, type: foreign_key_type
+
+      t.timestamps
+
+      t.index [:record_type, :record_id, :name],
+        name: "index_action_text_rich_texts_uniqueness", unique: true
+    end
+  end
+
+  private
+
+  def primary_and_foreign_key_types
+    config = Rails.configuration.generators
+    setting = config.options[config.orm][:primary_key_type]
+    primary_key_type = setting || :primary_key
+    foreign_key_type = setting || :bigint
+    [primary_key_type, foreign_key_type]
+  end
+end