AshJsonApi allows you to take resources created with Ash and build complete JSON:API compliant endpoints with just a few lines of code.
This is what AshJsonApi does:
- Route Creation: AshJsonApi defines routes and actions in your app based on resource configurations
- Deserialization: When an incoming HTTP request hits a AshJsonApi defined route/action, AshJsonApi will parse it from
/api/users?filter[admin]=trueinto a call to ash
- Query Execution: AshJsonApi then executes the parsed Ash Action (this is the integration point between AshJsonApi and Ash Core, where Ash Actions are defined)
- Serialization: AshJsonApi then serializes the result of the Ash Action into JSON API objects.
- Response: AshJsonApi then sends this JSON back to the client
- Schema Generation: AshJsonApi generates a machine-readable JSON Schema of your entire API and a route/action that can serve it
As you can see, Ash takes care of all of the data related work for a request (CRUD, Sorting, Filtering, Pagination, Side Loading, and Authorization) while AshJsonApi more or less replaces controllers and serializers.
The beauty of putting all of that data functionality into a non-web layer (Ash) is that it can be used in many contexts. A JSON:API is one context - but there are others such as GraphQL or just using an Ash Resource from other code within an Application. The decoupling of the web from data layers is why AshJsonApi is it's own hex package, as opposed to just a module within Ash.
Assume you have already built a resource using Ash such as this Post resource:
defmodule Post do use Ash.Resource, data_layer: Ash.DataLayer.Postgres actions do read :default create :default end attributes do attribute :name, :string end relationships do belongs_to :author, Author end end
As you can see, the resource takes care of interacting with the database, setting up attributes and relationships, as well as specifying actions (CRUD) that can be performed on the resource. What is now needed is to add a configuration for how this resource will interact with JSON:API
defmodule Post do use Ash.Resource, data_layer: AshPostgres, extensions: [AshJsonApi.Resource] ... json_api do routes do base "/posts" # Add a `GET /posts/:id` route, that calls into the :read action called :default get :default # Add a `GET /posts` route, that calls into the :read action called :default index :default end end ...
Then, update your API with the API extension and configuration:
defmodule MyApp.Api do use Ash.Api, extensions: [AshJsonApi.Api] json_api do ... end end
See the hex documentation for more.