getting-started-with-ash-json-api.md

Getting started with AshJsonApi

Installing AshJsonApi

Using Igniter (recommended)

mix igniter.install ash_json_api

Manually

This manual setup branches off from the Getting Started with Ash guide. If you aren't starting from there, replace the application name, Helpdesk, with your application name, and replace the Ash.Domain name, Helpdesk.Support with a domain or domains from your own application.

Add the ash_json_api dependency

In your mix.exs, add the Ash JSON API dependency:

  defp deps do
    [
      # .. other dependencies
      {:ash_json_api, "~> 1.0"},
    ]
  end

Accept json_api content type

Add the following to your config/config.exs.

# config/config.exs
config :mime,
  extensions: %{"json" => "application/vnd.api+json"},
  types: %{"application/vnd.api+json" => ["json"]}

This configuration is required to support working with the JSON:API custom mime type.

After adding the configuration above, compiling the project might throw an error:

ERROR! the application :mime has a different value set for key :types during runtime compared to compile time.

This can happen if :mime was already compiled before the configuration was changed and can be fixed by running

mix deps.compile mime --force

Create a router

Create a separate Router Module to work with your Domains. It will generate the routes for your Resources and provide the functions you would usually have in a Controller.

We will later forward requests from your Applications primary (Phoenix) Router to you Ash JSON API Router.

defmodule HelpdeskWeb.JsonApiRouter do
  use AshJsonApi.Router,
    # The api modules you want to serve
    domains: [Module.concat(["Helpdesk.Support"])],
    # optionally an open_api route
    open_api: "/open_api"
end

Whats up with Module.concat/1? {: .info}

This Module.concat/1 prevents a compile-time dependency from this router module to the domain modules. It is an implementation detail of how forward/2 works that you end up with a compile-time dependency on the schema, but there is no need for this dependency, and that dependency can have drastic impacts on your compile times in certain scenarios.

Additionally, your Resource requires a type, a base route and a set of allowed HTTP methods and what action they will trigger.

Add AshJsonApi.Plug.Parser to your endpoint

This handles any file uploads, if you have resource actions with the :file type.

plug Plug.Parsers,
  parsers: [:urlencoded, :multipart, :json, AshJsonApi.Plug.Parser], # <- add it to this list.
  pass: ["*/*"],
  json_decoder: Jason

You don't have to add this if you don't plan on doing any file uploads, but there is no cost to adding it, even if you don't use it.

Add the routes from your domain module(s)

To make your Resources accessible to the outside world, forward requests from your Phoenix router to the router you created for your domains.

For example:

scope "/api/json" do
  pipe_through(:api)

  forward "/helpdesk", HelpdeskWeb.JsonApiRouter
end

Configure your Resources and Domain and expose actions

These examples are based off of the Getting Started with Ash guide.

Add the AshJsonApi extension to your domain and resource

Using Igniter (recommended)

To set up an existing resource of your own with AshJsonApi, run:

mix ash.patch.extend Your.Resource.Name json_api

Manually

Add to your domain:

defmodule Helpdesk.Support do
  use Ash.Domain, extensions: [AshJsonApi.Domain]
  ...

And to your resource:

defmodule Helpdesk.Support.Ticket do
  use Ash.Resource, extensions: [AshJsonApi.Resource]
  # ...
  json_api do
    type "ticket"
  end
end

Define Routes

Routes can be defined on the resource or the domain. If you define them on the domain (which is our default recommendation), the resource in question must still use the AshJsonApi.Resource extension, and define its own type.

Defining routes on the domain

defmodule Helpdesk.Support do
  use Ash.Domain, extensions: [AshJsonApi.Domain]

  json_api do
    routes do
      # in the domain `base_route` acts like a scope
      base_route "/tickets", Helpdesk.Support.Ticket do
        get :read
        index :read
        post :open
      end
    end
  end
end

And then add the extension and type to the resource:

defmodule Helpdesk.Support.Ticket do
  use Ash.Resource, extensions: [AshJsonApi.Resource]
  # ...
  json_api do
    type "ticket"
  end
end

Defining routes on the resource

Here we show an example of defining routes on the resource.

defmodule Helpdesk.Support.Ticket do
  use Ash.Resource, extensions: [AshJsonApi.Resource]
  # ...
  json_api do
    type "ticket"

    routes do
      # on the resource, the `base` applies to all routes
      base "/tickets"

      get :read
      index :read
      post :open
      # ...
    end
  end
end

Check out the AshJsonApi.Resource documentation on Hex for more information.

Run your API

From here on out its the standard Phoenix behavior. Start your application with mix phx.server and your API should be ready to try out. Should you be wondering what routes are available, you can print all available routes for each Resource:

Helpdesk.Support.Ticket
|> AshJsonApi.Resource.Info.routes(Helpdesk.Support)

Make sure that all requests you make to the API use the application/vnd.api+json type in both the Accept and Content-Type (where applicable) headers. The Accept header may be omitted.

Examples:

1. Create a ticket

   curl -X POST 'localhost:4000/api/json/helpdesk/tickets' \
   --header 'Accept: application/vnd.api+json' \
   --header 'Content-Type: application/vnd.api+json' \
   --data-raw '{
     "data": {
       "type": "ticket",
       "attributes": {
         "subject": "This ticket was created through the JSON API"
       }
     }
   }'

2. Get all tickets

   curl 'localhost:4000/api/json/helpdesk/tickets'

3. Get a specific ticket

   # Add the uuid of a Ticket you created earlier
   curl 'localhost:4000/api/json/helpdesk/tickets/<uuid>'

Open API

If you want to expose your API via Swagger UI or Redoc, see the open api documentation.