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Version: v3.0

Using nested resources

This tutorial will walk you through extending the Search, attachments and tags Tutorial to support nested resources.

Prerequisites​

Ensure you have completed the Search, attachments and tags Tutorial.

Data model​

The following data model will be used for this tutorial.

Each blog post can have 1 or more Open Graph meta tags.

Create the model and database schema​

Generate the models and database schema for the application using the following commands

docker compose run --rm backend "rails g model og_meta_tag blog_post:references tag_name:string value:string"
docker compose run --rm backend "rails db:migrate"

Configure the models​

Update the model code files to extend the associations, validations and Rhino configuration for the model files as highlighted below

OgMetaTag​

app/models/og_meta_tag.rb
class OgMetaTag < ApplicationRecord
  belongs_to :blog_post

  # Rhino specific code
  rhino_owner :blog_post
  rhino_references %i[blog_post]

  validates :tag_name, presence: true
  validates :value, presence: true

  # Rhino specific code
  def display_name
    "#{tag_name}: #{value}"
  end
end
tip

By default Rhino will use the name or title attribute of the model, but this can be overridden by defining a display_name method.

BlogPost​

app/models/blog_post.rb
class BlogPost < ApplicationRecord
  belongs_to :blog
  has_many :og_meta_tags, dependent: :destroy

  accepts_nested_attributes_for :og_meta_tags, allow_destroy: true

  acts_as_taggable_on :tags

  # Rhino specific code
  rhino_owner :blog
  rhino_references [:blog, :og_meta_tags]

  validates :title, presence: true
  validates :body, presence: true
end

Configure the REST API​

Update the Rhino configuration so that OgMetaTag is available through the Rest API.

config/initializers/rhino.rb
- config.resources += ['User', 'Account', 'Blog', 'BlogPost', "Category"]
+ config.resources += ['User', 'Account', 'Blog', 'BlogPost', "Category", "OgMetaTag"]
info

accepts_nested_attributes_for is part of Rails and allows for child model attributes to be passed through the parent model.

Restart the server​

docker compose restart backend

Attach OpenGraph meta tags to a blog post​

You will now be able to add one or more OpenGraph meta tags to a blog post, as well as edit and delete them.