Craft GraphQL APIs in Elixir with Absinthe/

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Login API

Login API

Learn about how to define the mutation for your API.

We'll cover the following...

Mutation for API

With the underlying database work all set, the next task is to define the mutation for our API. We head over to our Absinthe schema and add a :login mutation field to the root mutation type:

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mutation do
  field :login, :session do
    arg :email, non_null(:string)
    arg :password, non_null(:string) 
    arg :role, non_null(:role)
    resolve &Resolvers.Accounts.login/3
  end
  # «Other mutation fields»
end

The mutation requires an email address, password, and role, and it returns a :session type. We will create a new type module to house this type and others like it:

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defmodule PlateSlateWeb.Schema.AccountsTypes do 
  use Absinthe.Schema.Notation
  object :session do
     field :token, :string 
     field :user, :user
  end
  enum :role do 
    value :employee 
    value :customer
  end
  interface :user do
    field :email, :string 
    field :name, :string 
    resolve_type fn
       %{role: "employee"}, _ -> :employee
       %{role: "customer"}, _ -> :customer 
    end
  end
  object :employee do 
    interface :user
    field :email, :string 
    field :name, :string
  end
  object :customer do
    interface :user
    field :email, :string
    field :name, :string
    field :orders, list_of(:order)
  end
end

There are a couple of interesting types here. At the top, we have the :session object that returns from the :login mutation, which contains an API token ...