Getting Started With Graphql

Get familiar with Ash resources

If you haven't already, read the getting started guide for Ash. This assumes that you already have resources set up, and only gives you the steps to add AshGraphql to your resources/apis.

Bring in the ash_graphql, and absinthe_plug dependencies

def deps()
  [
    ...
    {:ash_graphql, "~> x.x"}
    {:absinthe_plug, "~> x.x"},
  ]
end

Use mix hex.info ash_graphql and mix hex.info absinthe_plug to quickly find the latest versions.

Add the API Extension

defmodule MyApi do
  use Ash.Api, extensions: [
    AshGraphql.Api
  ]

  graphql do
    authorize? false # Defaults to `true`, use this to disable authorization for the entire API (you probably only want this while prototyping)
  end
end

Add graphql to your resources

defmodule Post do
  use Ash.Resource,
    extensions: [
      AshGraphql.Resource
    ]

  graphql do
    type :post

    queries do
      get :get_post, :read # <- create a field called `get_post` that uses the `read` read action to fetch a single post
      read_one :current_user, :current_user # <- create a field called `current_user` that uses the `current_user` read action to fetch a single record
      list :list_posts, :read # <- create a field called `list_posts` that uses the `read` read action to fetch a list of posts
    end

    mutations do
      # And so on
      create :create_post, :create
      update :update_post, :update
      destroy :destroy_post, :destroy
    end
  end
end

Add AshGraphql to your schema

If you don't have an absinthe schema, you can create one just for ash.

Define a context/1 function, and call AshGraphql.add_context/2 with the current context and your apis. Additionally, add the Absinthe.Middleware.Dataloader to your plugins, as shown below. If you're starting fresh, just copy the schema below and adjust the module name and api name.

defmodule MyApp.Schema do
  use Absinthe.Schema

  @apis [MyApp.Api]

  use AshGraphql, apis: @apis

  # The query and mutation blocks is where you can add custom absinthe code
  query do
  end

  mutation do
  end

  def context(ctx) do
    AshGraphql.add_context(ctx, @apis)
  end

  def plugins() do
    [Absinthe.Middleware.Dataloader | Absinthe.Plugin.defaults()]
  end
end

Connect your schema

Using Plug

If you are unfamiliar with how plug works, this guide will be helpful for understanding it. It also guides you through adding plug to your application.

Then you can use a Plug.Router and forward to your plugs similar to how it is done for phoenix:

forward "/gql",
  to: Absinthe.Plug,
  init_opts: [schema: YourSchema]

forward "/playground",
  to: Absinthe.Plug.GraphiQL,
  init_opts: [
    schema: YourSchema,
    interface: :playground
  ]

Using Phoenix

You will simply want to add some code to your router, like so.

You will also likely want to set up the "playground" for trying things out.

scope "/" do
  forward "/gql", Absinthe.Plug, schema: YourSchema

  forward "/playground",
          Absinthe.Plug.GraphiQL,
          schema: YourSchema,
          interface: :playground
end

If you started with mix new ... instead of mix phx.new ... and you want to still use phoenix, the fastest path that way is typically to just create a new phoenix application and copy your resources/config over.

3.5 KiB Raw Blame History