How recursively fetch a relationship to generate a non table field in a resource?

Questions & Help Questions
,
7

Oh right, ty! Updated and had to add to add this to the calculation to stop errors:

  @impl true
  def load(_query, _opts, _context) do
    [:parent]
  end

on the resource :path is defined as

  calculations do
    calculate :path,
              {:array, :string},
              ContentCove.Calculations.Path
  end

However the values displayed dont seem correct since path is supposed to return an array of strings. In the admin ui i see single string values that are seemingly incorrect for each topic.

image
image1200×467 43.9 KB

defmodule ContentCove.Calculations.Path do
  use Ash.Resource.Calculation

  alias ContentCove.Articles.Topic

  require Ash.Query

  @impl true
  def calculate(topic, _, _) do
    fetch_all_topics(topic)
    |> Enum.map(fn {_, topic} -> to_string(topic.slug) end)
    |> IO.inspect()
    |> Enum.reverse()
  end

  @impl true
  def load(_query, _opts, _context) do
    [:parent]
  end

  defp fetch_all_topics(topics, acc \\ %{}) do
    acc = Map.merge(acc, Map.new(topics, fn topic -> {topic.id, topic} end))

    #dbg(acc)

    topics
    |> Enum.map(& &1.parent_id)
    |> Enum.filter(fn parent_id ->
      parent_id && !Map.has_key?(acc, parent_id)
    end)
    |> case do
      [] ->
        acc

      unfetched_parent_ids ->
        Topic
        |> Ash.Query.filter(id in ^unfetched_parent_ids)
        |> Ash.read!()
        |> fetch_all_topics(acc)
    end
  end
end

Judging by the terminal output it looks like a single array is built and somehow each row in the admin ui is being given 1 value from the array i.e ["entertainment", "local-sport", "celebrities", "sport", "cricket"] that is the output from the inspect above in calculate.

If i hardcode ["test1", "test2"] to be returned from the calculate function in the admin ui it shows 1 value from the array for each row and only returns 2 rows instead of the correct number shown in the screenshot. Furthermore I though maybe its supposed to return an array of arrays for each row but that too only displays s single value in the admin for each row :thinking: