Absinthe 1.4.2 -- "Cannot query field" on explicit join ecto query that contains select: %{custom struct}

Questions / Help
,
1

I have a Book table which has_many BookTitle.

the Book Ecto schema is:

  schema "book" do
    field :absolute_id, :integer
    field :basename, :string
    field :uuid, Ecto.UUID

    has_many :chapter, Allscripture.Chapter
    has_many :booktitle, Allscripture.BookTitle
    
  end

BookTitle(book_title.ex):

  schema "booktitle" do
    field :language_id, :string
    field :localizedname, :string
    field :uuid, Ecto.UUID
    field :book_id, :id
  end

and my absinthe schema is(schema.ex):

  object :book do
    field :uuid, :string
    field :languageId, :string
    field :title, :string
    field :localizedTitle, :string
  end

it does not match the postgresql db schema because the API is meant to return a join of information from Book and BookTitle.

this is my graphql query(schema.ex):

  alias Allscripture.{Book, BookTitle, Repo}
  query do
    field :books, list_of(:book) do
      arg :language, :string
      resolve fn 
        _, %{language: lang}, _ when is_binary(lang) ->
          query = from book in Book,
            join: title in BookTitle, 
            on: book.id == title.book_id,
            where: title.language_id == ^lang,
            select: %{uuid: book.uuid, 
                        languageId: title.language_id, 
                        title: book.basename, 
                        localizedTitle: title.localizedname},
            order_by: book.absolute_id   

          {:ok, Repo.all(query)}
...

I used an explicit join to join BookTitle to Book because my efforts with preload were a dead-end. Anyway, when I do a graphql query (localhost:4000/graphiql):

{
  books(language: "pt") {
    languageId
    localizedTitle
    title
    uuid
  }
}

Absinthe gives me an error array:

{
  "errors": [
    {
      "message": "Cannot query field \"languageId\" on type \"Book\". Did you mean \"languageId\"?",
      "locations": [
        {
          "line": 3,
          "column": 0
        }
      ]
    },
    {
      "message": "Cannot query field \"localizedTitle\" on type \"Book\". Did you mean \"localizedTitle\"?",
      "locations": [
        {
          "line": 4,
          "column": 0
        }
      ]
    }
  ]
}

when testing the ecto query in iex, it seems to return the correct data set.

What is the correct way to tell Absinthe that it shouldn’t depend upon the database schema but the database query response to validate the graphql query response? Or am I doing things wrong?

Michael

1 Like
2

Try to name your fields in snake_case like :language_id. Absinthe will convert your query accordingly.

3

Yup this is spot on advice. The issue is that if you are querying for localizedTitle it’s gonna expect an internal field called :localized_title.

4

That did it! Thanks @zimt28

BTW @benwilson512 I’m going through b3 of your book. Lovin it!

1 Like