drumusician Posts - Answer Overflow

drumusician

•Created by drumusician on 9/22/2023 in #support

Cannot return null for non-nullable field

Hi Guys, I have an attribute in a resource that is a jsonb object in postgres and am defaulting it to an empty object in the db and also want to return it as an emoty object in GraphQL. However it seems to be returning null if the the object is empty... Is this something AshGraphQL is doing under the hood?

15 replies

AEAsh Elixir

•Created by drumusician on 9/13/2023 in #support

sort many_to_many

I thought I had asked this question before, but can't seem to find it... It seems like a very common use case, but not sure how to go about this. Is it possible to sort a many_to_many relationship based on a field in the join table. ie. if I have a Playlist:

defmodule Playlist do
  relationships do
    has_many :playlist_entries, PlaylistEntry
    many_to_many :items, Item
  end
end

defmodule Playlist do
  relationships do
    has_many :playlist_entries, PlaylistEntry
    many_to_many :items, Item
  end
end

and an Item:

defmodule Item do
...
end

defmodule Item do
...
end

And a PlaylistEntry:

defmodule PlaylistEntry
  relationships do
    belongs_to :item, Item
    belongs_to :playlist, Playlist
  end

  attributes do
    attribute :position, :integer
  end
end

defmodule PlaylistEntry
  relationships do
    belongs_to :item, Item
    belongs_to :playlist, Playlist
  end

  attributes do
    attribute :position, :integer
  end
end

And I want to simply load this in graphql by just adding the items:

query  {
  playlist {
    items {
      name
      //ordered by position in playlist_entry
    }
  }
}

query  {
  playlist {
    items {
      name
      //ordered by position in playlist_entry
    }
  }
}

I know that in graphql not all values that are not needed in the read are selected, but apart from graphQL is there a way to get this sorting happening. Thanks all!

9 replies

AEAsh Elixir

•Created by drumusician on 9/11/2023 in #support

ManualRead not resolving in graphQL

Hi All, I have created a ManualRead module to implement a tricky relationship which has defaults that can be overridden. Before going too much into details, this ManualRead is working fine when I use the code interface, but when I call the same action through graphQL the values I expect are all nil. It is a bit too long to paste here, but was wondering if there is something general I need to think of when doing this?

146 replies

AEAsh Elixir

•Created by drumusician on 9/8/2023 in #support

InvalidFilterValue for read action

I have this relatively simple read action, but it keeps on failing with a %Ash.Error.Query.InvalidFilterValue

 read :for_organisation do
  argument(:organisation_id, :integer) do
    allow_nil?(false)
  end

  prepare(fn query, _context ->
    query
    |> Ash.Query.load([:game_meta])
    |> Ash.Query.filter(game_meta.organisation_id == ^arg(:organisation_id))
  end)
end

 read :for_organisation do
  argument(:organisation_id, :integer) do
    allow_nil?(false)
  end

  prepare(fn query, _context ->
    query
    |> Ash.Query.load([:game_meta])
    |> Ash.Query.filter(game_meta.organisation_id == ^arg(:organisation_id))
  end)
end

This is the relationship in game_meta:

  belongs_to(:organisation, McFun.Games.Organisation,
    attribute_type: :integer,
    attribute_writable?: true
  )

  belongs_to(:organisation, McFun.Games.Organisation,
    attribute_type: :integer,
    attribute_writable?: true
  )

Any ideas why this is happening?

7 replies

AEAsh Elixir

•Created by drumusician on 6/29/2023 in #support

many_to_many with non-default attribute not preloading...

So, I have a many to many relationship I'm strugling with. It must be something silly, but I just can't make it work. I have a resource called Game, which is actually for a table called assets, so in the join table one of the attributes is asset_id and not game_id. The join table is called playlist_entries Any help would be greatly appreciated. Basically it is not loading the games correctly for the playlist. Addng the full resources made the post too long, so hopefully this will shed enough light... Playlist

defmodule McFun.Games.Playlist do
  use Ash.Resource,
    data_layer: AshPostgres.DataLayer,
    extensions: [
      AshGraphql.Resource
    ]

  alias McFun.Games.PlaylistEntry
  alias McFun.Games.Game

  postgres do
    schema("games")
    repo(McCore.Repo)
    table("playlists")
  end

  relationships do
    many_to_many :games, Game do
      through(PlaylistEntry)
      source_attribute_on_join_resource(:playlist_id)
      destination_attribute_on_join_resource(:asset_id)
    end
  end
end

defmodule McFun.Games.Playlist do
  use Ash.Resource,
    data_layer: AshPostgres.DataLayer,
    extensions: [
      AshGraphql.Resource
    ]

  alias McFun.Games.PlaylistEntry
  alias McFun.Games.Game

  postgres do
    schema("games")
    repo(McCore.Repo)
    table("playlists")
  end

  relationships do
    many_to_many :games, Game do
      through(PlaylistEntry)
      source_attribute_on_join_resource(:playlist_id)
      destination_attribute_on_join_resource(:asset_id)
    end
  end
end

PlaylistEntry

  postgres do
    schema("games")
    repo(McCore.Repo)
    table("playlist_entries")
  end

  relationships do
    belongs_to :playlist, Playlist do
      source_attribute(:playlist_id)
      primary_key?(true)
      allow_nil?(false)
      attribute_type(:integer)
    end

    belongs_to :game, Game do
      source_attribute(:asset_id)
      primary_key?(true)
      allow_nil?(false)
      attribute_type(:integer)
    end

  postgres do
    schema("games")
    repo(McCore.Repo)
    table("playlist_entries")
  end

  relationships do
    belongs_to :playlist, Playlist do
      source_attribute(:playlist_id)
      primary_key?(true)
      allow_nil?(false)
      attribute_type(:integer)
    end

    belongs_to :game, Game do
      source_attribute(:asset_id)
      primary_key?(true)
      allow_nil?(false)
      attribute_type(:integer)
    end

Game

  postgres do
    schema("games")
    repo(McCore.Repo)
    table("assets")
  end
end

  postgres do
    schema("games")
    repo(McCore.Repo)
    table("assets")
  end
end

33 replies

AEAsh Elixir

•Created by drumusician on 6/11/2023 in #support

Custom / virtual fields on read

Hi All, I am creating an API based on an old system and can't modify the original, but I want to change the way the resources are read. More specifically I want to set a certain virtual field based on the value of an existing database field. Normally this is something I would achieve with a virtual field and then modify the output in the view layer. But I understand the idiomatic way in Ash is to push as much as possible into the resource. I read in another post that arguments are basically the equivalent of virtual fields, so looked into setting those based on an attribute value. What would be the best approach to achieve something like this. I already experimented with Ash.Query a bit, but not sure how to achieve reading an attribute from the fetched resource and setting an argument based on that. Any advise and/or guidance is much appreciated. I tried to find it in the docs but am a bit lost where to look... Thanks!

17 replies

AEAsh Elixir

•Created by drumusician on 5/30/2023 in #support

@derive Jason.Encoder

Hi All, I have an embedded Json object in Ash which is consumed by GraphQL. I have configured graphQL to use json instead of json_string like described here => https://hexdocs.pm/ash_graphql/use-json-with-graphql.html But now I get a Jason.Encoder error. In Ecto this can be solved by adding @derive Jason.Encoder in the module. Is there a way in Ash to do this?

8 replies

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