Absinthe.Plug.Types (absinthe_plug v1.5.7) View Source

This module provides GraphQL types that may be useful in Absinthe schema and type modules.

:upload

Absinthe.Plug can be used to upload files via GraphQL.

For example, the following schema includes a mutation field that accepts multiple uploaded files as arguments (:users and :metadata):

defmodule MyAppWeb.Schema do
  use Absinthe.Schema

  # Important: Needed to get the `:upload` type
  import_types Absinthe.Plug.Types

  mutation do
    field :upload_file, :string do
      arg :users, non_null(:upload)
      arg :metadata, :upload

      resolve fn args, _ ->
        args.users # this is a `%Plug.Upload{}` struct.

        {:ok, "success"}
      end
    end
  end
end

To send a mutation that includes a file upload, you need to use the multipart/form-data content type. For example, using cURL:

$ curl -X POST -F query='mutation { uploadFile(users: "users_csv", metadata: "metadata_json") }' -F users_csv=@users.csv -F metadata_json=@metadata.json localhost:4000/graphql

Note how there is a correspondance between the value of the :users argument and the -F option indicating the associated file.

By treating uploads as regular arguments we get all the usual GraphQL argument benefits (such as validation and documentation), something we wouldn't get if we were merely putting them in the context.