Getting Started With GraphQL

Get familiar with Ash resources

If you haven't already, read the Ash Getting Started Guide. This assumes that you already have resources set up, and only gives you the steps to add AshGraphql to your resources/domains.

Installation

mix igniter.install ash_graphql

def deps()
  [
    ...
    {:ash_graphql, "~> 1.7.9"}
  ]
end

defmodule Helpdesk.GraphqlSchema do
  use Absinthe.Schema

  # Add your domains here
  use AshGraphql,
    domains: [Your.Domains]

  query do
    # Custom absinthe queries can be placed here
    @desc "Remove me once you have a query of your own!"
    field :remove_me, :string do
      resolve fn _, _, _ ->
        {:ok, "Remove me!"}
      end
    end
  end

  mutation do
    # Custom absinthe mutations can be placed here
  end
end

pipeline :graphql do
  plug AshGraphql.Plug
end

scope "/gql" do
  pipe_through [:graphql]

  forward "/playground",
          Absinthe.Plug.GraphiQL,
          schema: Module.concat(["Helpdesk.GraphqlSchema"]),
          interface: :playground

  forward "/",
    Absinthe.Plug,
    schema: Module.concat(["Helpdesk.GraphqlSchema"])
end

plug AshGraphql.Plug

forward "/gql",
  to: Absinthe.Plug,
  init_opts: [schema: Module.concat(["Helpdesk.GraphqlSchema"])]

forward "/playground",
  to: Absinthe.Plug.GraphiQL,
  init_opts: [
    schema: Module.concat(["Helpdesk.GraphqlSchema"]),
    interface: :playground
  ]

Select domains to show in your GraphQL

In the use AshGraphql call in your schema, you specify which domains you want to expose in your GraphQL API. Add any domains that will have AshGraphql queries/mutations to the domains list. For example:

use AshGraphql, domains: [Your.Domain1, Your.Domain2]

Adding Queries and Mutations

Some example queries/mutations are shown below. If no queries/mutations are added, nothing will show up in the GraphQL API, so be sure to set one up if you want to try it out.

Queries & Mutations on the Resource

Here we show queries and mutations being added to the resource, but you can also define them on the domain. See below for an equivalent definition

defmodule Helpdesk.Support.Ticket do
  use Ash.Resource,
    ...,
    extensions: [
      AshGraphql.Resource
    ]

  graphql do
    type :ticket

    queries do
      # Examples

      # create a field called `get_ticket` that uses the `read` read action to fetch a single ticke
      get :get_ticket, :read
      # create a field called `most_important_ticket` that uses the `most_important` read action to fetch a single record
      read_one :most_important_ticket, :most_important

      # create a field called `list_tickets` that uses the `read` read action to fetch a list of tickets
      list :list_tickets, :read
    end

    mutations do
      # Examples

      create :create_ticket, :create
      update :update_ticket, :update
      destroy :destroy_ticket, :destroy
    end
  end

  ...
end

Queries & Mutations on the Domain

defmodule Helpdesk.Support.Ticket do
  use Ash.Resource,
    ...,
    extensions: [
      AshGraphql.Resource
    ]

  # The resource still determines its type, and any other resource/type-based
  # configuration
  graphql do
    type :ticket
  end

  ...
end

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

  ...
  graphql do
    # equivalent queries and mutations, but the first argument
    # is the resource because the domain can define queries for
    # any of its resources
    queries do
      get Helpdesk.Support.Ticket, :get_ticket, :read
      read_one Helpdesk.Support.Ticket, :most_important_ticket, :most_important
      list Helpdesk.Support.Ticket, :list_tickets, :read
    end

    mutations do
      create Helpdesk.Support.Ticket, :create_ticket, :create
      update Helpdesk.Support.Ticket, :update_ticket, :update
      destroy Helpdesk.Support.Ticket, :destroy_ticket, :destroy
    end
end

What's next?

Topics:

• GraphQL Generation

How Tos:

• Authorize With GraphQL
• Handle Errors
• Use Enums with GraphQL
• Use JSON with GraphQL