ActionText: All the ways to render an ActionText Attachment

There’s so many ways to render an ActionText attachment, we can change the app/views/active_storage/blobs/_blob.html.erb as we saw in a previous post. This will apply to all ActiveStorage blobs. However, you may want more fine grained control for things like CustomAttachments. You’ll also find some of the ways to change a models ActionText rendering method:

https://github.com/rails/rails/blob/b96ddea5f0b4ff8ed6e9dfe4df62f7571b147b11/actiontext/lib/action_text/attachable.rb#L70-L76

These methods are particularly useful when creating Custom Attachments. We won’t cover those in this post, but that’s where the above methods will come into play.

Let’s talk about what each does:

to_trix_content_attachment_partial_path

Under the hood Rails calls value.to_trix_html when you render within your Trix editor using the rich_text_area form helper.

Erb 
<%= form_with model: @post do |f| %>
  <!-- calls @post.body.to_trix_html -->
  <% f.rich_text_area :body %>
<% end %>

https://github.com/rails/rails/blob/0c97d1db023de4df6d2df8829e5ee311ff0d0e28/actiontext/app/helpers/action_text/tag_helper.rb#L36

So to_trix_content_attachment_partial_path is what users will see in their editor.

to_attachable_partial_path

When the user hits save, then the editor will show the final output by calling:

to_attachable_partial_path

This allows you to create 2 experiences, one for the editor, and one for the final rendering.

to_partial_path

to_partial_path is a standard rendering path for models. This is used as a shortcut for to_attachable_partial_path and to_trix_content_attachment_partial_path.

For more on to_partial_path it’s worth checking out this Thoughtbot article on rendering.

https://thoughtbot.com/blog/rendering-collections-in-rails

Here’s what it may look like all together in an actual attachable model:

With an ActiveRecord Model

Ruby 
class User < ApplicationRecord
  include ActionText::Attachable

  # app/views/users/_mention.html.erb
  # rendered in final rendering
  def to_attachment_partial_path
    "users/mention"
  end

  # app/views/users/_thumbnail.html.erb
  # rendered in Trix editor
  def to_trix_content_attachment_partial_path
    "users/thumbnail"
  end

  # app/views/users/_user.html.erb
  # rendered when calling <%= render User.first %>
  def to_partial_path
    "users/user"
  end
end

With a non-ActiveRecord model

Ruby 
class Youtube
  include ActiveModel::Model
  include ActiveModel::Attributes
  include GlobalID::Identification
  include ActionText::Attachable

  # to be eligible to create an "sgid" we need to implement an
  #   "id" attribute.
  attribute :id

  # app/views/youtubes/_embed.html.erb
  # rendered in final rendering
  def to_attachment_partial_path
    "youtubes/embed"
  end

  # app/views/youtubes/_thumbnail.html.erb
  # rendered in Trix editor
  def to_trix_content_attachment_partial_path
    "youtubes/thumbnail"
  end

  # app/views/youtubes/_youtube.html.erb
  # rendered when calling <%= render Youtube.first %>
  def to_partial_path
    "youtubes/youtube"
  end
end

Conclusion

For more on Attachments, particularly custom attachments checkout the following resources:

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