Jason Posts - Answer Overflow

Jason

•Created by Jason on 5/6/2025 in #support

After-commit hook?

I'm running into a race condition issue when I insert a row to a table with the resource's create action, and the subscriber to the notification calculates the resulting row count. What's the right way to do this in Ash? Adding 'Process.sleep(1000)' seems to help but I'm hoping there is a better way. Thanks.

11 replies

AEAsh Elixir

•Created by Jason on 9/17/2023 in #support

Filter check is returning an error tuple, rather than filtering rows.

I'm trying to use policies to filter out rows whose visibility attribute is not 1. The table contains some rows where visibility == 2, so I expected the query will filter those out.

    policy action_type(:read) do
      forbid_if Invisible
    end

    policy action_type(:read) do
      forbid_if Invisible
    end

But Task |> Ash.Query.for_read(:read) |> Tasks.read() returns an error tuple like this. What am I missing?

{:error,
 %Ash.Error.Forbidden{
   errors: [
     %Ash.Error.Forbidden.Policy{
       scenarios: [],
       facts: %{
         false => false,
         true => true,
         {Ash.Policy.Check.ActionType, [type: :read, access_type: :filter]} => true
       },
       filter: nil,
       policy_breakdown?: false,

{:error,
 %Ash.Error.Forbidden{
   errors: [
     %Ash.Error.Forbidden.Policy{
       scenarios: [],
       facts: %{
         false => false,
         true => true,
         {Ash.Policy.Check.ActionType, [type: :read, access_type: :filter]} => true
       },
       filter: nil,
       policy_breakdown?: false,

23 replies

AEAsh Elixir

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

Resource MyApp.Accounts.FriendLink is not present in any known Ash.Api module.

I'm getting the above warning even though this module is indeed listed in the registry. What am I missing?

defmodule MyApp.Accounts.Registry do
  use Ash.Registry,
    extensions: Ash.Registry.ResourceValidations

  entries do
    entry MyApp.Accounts.User
    entry MyApp.Accounts.FriendLink

defmodule MyApp.Accounts.Registry do
  use Ash.Registry,
    extensions: Ash.Registry.ResourceValidations

  entries do
    entry MyApp.Accounts.User
    entry MyApp.Accounts.FriendLink

config :myapp, ash_apis: [MyApp.Accounts, ]

config :myapp, ash_apis: [MyApp.Accounts, ]

12 replies

AEAsh Elixir

•Created by Jason on 9/10/2023 in #support

(Postgrex.Error) ERROR 42P18 (indeterminate_datatype) could not determine data type of parameter $1

Gotting the above error while try this code for a regex search. Ash.Query.filter(fragment("task_id ~* '?\\d+'", ^prefix)) The Ecto doc suggests explicitly defining type withtype(^prefix, :string) but I'm not sure how it's supposed to fit in as an Ash.Query. expression.

17 replies

AEAsh Elixir

•Created by Jason on 7/17/2023 in #support

How to determine if the current page is the last or first page in Keyset pagination

I may be missing this from the documentation, but is there a way to find out if the current "page" is the firsrt or the last?

3 replies

AEAsh Elixir

•Created by Jason on 6/25/2023 in #support

no route found for POST /admin

With 1 ash_admin("/admin")` in the router.ex, I can open the admin site and see it perform some actions, but for some others, I get "no route found for POST /admin ". These are some simple read actions with a couple of arguments that I'm running, if that matters. Thanks.

73 replies

AEAsh Elixir

•Created by Jason on 6/20/2023 in #support

How to assign a default value to existing rows via Ash.postgres generated migration code

When a non-null column is added, is there a way to specify a default value to assign to the new column for existing records? I believe in Ecto, it's done something like this, but I'm curious if this can be done through Ash DSL.

add :new_field, :string, default: "default value"

add :new_field, :string, default: "default value"

If it makes a difference, the new column in my case is a source attribute for a relationship as in something like this. (So manually adding default: "default value" actually causes a foreign_key_violation., which is a different issue on its own.)

    belongs_to :theme, Items.Theme do
      api Items
      allow_nil? false
      destination_attribute :destination_new_field
      source_attribute :new_field
      attribute_type :integer
    end

    belongs_to :theme, Items.Theme do
      api Items
      allow_nil? false
      destination_attribute :destination_new_field
      source_attribute :new_field
      attribute_type :integer
    end

4 replies

AEAsh Elixir

•Created by Jason on 6/17/2023 in #support

attribute match constraints error message

When validating email format using regex, is there an easier way to show a more user friendly validation error message such as "invalid email format" rather than the default "must match the pattern ~r/[a-z...."? I believe it can be done inside action definition, but thought I might be missing an easier way to do the same in the attribute definition.

    attribute :email, :ci_string do
      allow_nil? false
      constraints match: ~r/^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$/
    end

    attribute :email, :ci_string do
      allow_nil? false
      constraints match: ~r/^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$/
    end

4 replies

AEAsh Elixir

•Created by Jason on 6/14/2023 in #support

An aggregate field loaded in create action isn't available for pub_sub?

publish :create, ["update", :aggregate_field1] in one of my resources fails with the following error, despite the fact that change load(:aggregate_field1) is in the action definition. If I remove the publish setting from pub_sub, the create action succeeds, with the :aggregate_field1 properly loaded to the changeset. I wonder if something changed about how pub_sub works in Ash lately, because my pub_sub and create action codes used to work fine. I did recently update ash to the latest version. Thanks.

89 replies

AEAsh Elixir

•Created by Jason on 6/9/2023 in #support

What happens when :prev page request is used but there is no previous page?

Need help understanding how keyset pagination works. Here are the steps I took. 1. 'search-change' handle_event does the initial search properly. The query output is saved in a variable called page. 2. When the 'prev'' button is clicked triggering 'prev-page' handler, (as expected) nothing happens. 3. When the "next" button is clicked triggering 'next-page' handler, nothing happens. I expected it to return the iintial search results again, or the set after that.

  def handle_event("search-change", %{"search" => search}, socket) do
 
    query = Ash.Query.filter(User, ilike(username, "%" <> ^search <> "%"))

    page = User.read!(query: query)

    searched_users = page.results

    {:noreply,
     socket
     |> assign(:page, page)
     |> stream(:searched_users, searched_users, reset: true)}
  end

  def handle_event("prev-page", params, socket) do
    page = MyApp.Accounts.page!(socket.assigns.page, :prev)

    {:noreply,
     socket
     |> assign(:page, page)
     |> stream(:searched_users, page.results, at: 0)}
  end

  def handle_event("search-change", %{"search" => search}, socket) do
 
    query = Ash.Query.filter(User, ilike(username, "%" <> ^search <> "%"))

    page = User.read!(query: query)

    searched_users = page.results

    {:noreply,
     socket
     |> assign(:page, page)
     |> stream(:searched_users, searched_users, reset: true)}
  end

  def handle_event("prev-page", params, socket) do
    page = MyApp.Accounts.page!(socket.assigns.page, :prev)

    {:noreply,
     socket
     |> assign(:page, page)
     |> stream(:searched_users, page.results, at: 0)}
  end

` Do I need to do something to prevent :prev page request where there is no previous page? If so, how do I do that? I saw this example, but thought page request is a simpler way to do the same.

next_page = Api.read(Resource, page: [limit: 10, after: last_record.__metadata__.keyset])

next_page = Api.read(Resource, page: [limit: 10, after: last_record.__metadata__.keyset])

15 replies

AEAsh Elixir

•Created by Jason on 5/31/2023 in #support

Deleting intermediary table record in a many_to_many relationship

In this example (https://hexdocs.pm/ash/2.6.18/managing-relationships.html) that Post and Tag have a many_to_many relationshp through PostTag, how do I make it so that the deletion of Post also deletes the record in PostTag , but not Tag? In post.ex, I have this action

destroy :delete_post do
end

destroy :delete_post do
end

which issues this error.

** (Ash.Error.Invalid) Input Invalid
* Invalid value provided for id: would leave records behind.
nil

** (Ash.Error.Invalid) Input Invalid
* Invalid value provided for id: would leave records behind.
nil

I tried adding manage_relationship with various type options to this but couldn't get it to do what I want.

5 replies

AEAsh Elixir

•Created by Jason on 5/14/2023 in #support

authorize_url for Google oauth

Hi @jart I was able to get github oauth to work following the getting started with Github guide, and now trying to get google oauth to work using oauth2. The doc's example for the authorize_url value is this.

authorize_url fn _, _ -> {:ok, "https://exampe.com/authorize"} end

authorize_url fn _, _ -> {:ok, "https://exampe.com/authorize"} end

If the path 'authorize' should be added to the router, I'm not sure what kind of module it should point to. Can you give me some pointers? I tried /auth/user/google/ as the authorize_url but it causes an ERR_TOO_MANY_REDIRECTS browser error, so I'm guessing that's not the right url.

3 replies

AEAsh Elixir

•Created by Jason on 5/9/2023 in #support

submit_errors: [id: {"has already been taken", []}],

When a for_create form is submitted, I get this error. Assuming the id it's referring to is "form", I'm not sure why it thinks it has been taken.

  api: MyApp.Tweets,
  method: "post",
  submit_errors: [id: {"has already been taken", []}],
  id: "form",
  transform_errors: nil,
...

  api: MyApp.Tweets,
  method: "post",
  submit_errors: [id: {"has already been taken", []}],
  id: "form",
  transform_errors: nil,
...

The form is created using apply_action called from the mount action (similar to the Ash twitter clone example).

  defp apply_action(socket, :new, _params) do
    current_user = socket.assigns.current_user

    form =
      AshPhoenix.Form.for_create(MyApp.Tweets.Tweet, :create,
        api: MyApp.Tweets,
        forms: [
          items: [

  defp apply_action(socket, :new, _params) do
    current_user = socket.assigns.current_user

    form =
      AshPhoenix.Form.for_create(MyApp.Tweets.Tweet, :create,
        api: MyApp.Tweets,
        forms: [
          items: [

7 replies

AEAsh Elixir

•Created by Jason on 5/9/2023 in #support

Could not relate to actor, as no actor was found (and :allow_nil? is false

When I submit a form that triggers :create action which contains change relate_actor(:author), I get this error. What causes no actor to be found despite that there is a logged in user?

  submit_errors: [
    author: {"Could not relate to actor, as no actor was found (and :allow_nil? is false)",
     []}
  ],

  submit_errors: [
    author: {"Could not relate to actor, as no actor was found (and :allow_nil? is false)",
     []}
  ],

8 replies

AEAsh Elixir

•Created by Jason on 5/7/2023 in #support

MyApp.Secrets must implement the 'AshAuthentication.Secret` behaviour.

I followed the example here (https://ash-hq.org/docs/guides/ash_authentication/latest/github-quickstart) but ran into this error. It talks about password_reset which I'm not sure where it's coming from.

** (EXIT from #PID<0.104.0>) an exception was raised:
    ** (Spark.Error.DslError) [nil]
 password_reset:
  `MyApp.Secrets` must implement the `AshAuthentication.Secret` behaviour.
        lib/MyApp/accounts/resources/user.ex:1: anonymous fn/1 in MyApp.Accounts.User.__verify_ash_dsl__/1
        (elixir 1.14.1) lib/enum.ex:975: Enum."-each/2-lists^foreach/1-0-"/2
        lib/MyApp/accounts/resources/user.ex:1: MyApp.Accounts.User.__verify_ash_dsl__/1
        (elixir 1.14.1) lib/enum.ex:975: Enum."-each/2-lists^foreach/1-0-"/2
        (elixir 1.14.1) lib/module/parallel_checker.ex:239: Module.ParallelChecker.check_module/2
        (elixir 1.14.1) lib/module/parallel_checker.ex:78: anonymous fn/5 in Module.ParallelChecker.spawn/3

** (EXIT from #PID<0.104.0>) an exception was raised:
    ** (Spark.Error.DslError) [nil]
 password_reset:
  `MyApp.Secrets` must implement the `AshAuthentication.Secret` behaviour.
        lib/MyApp/accounts/resources/user.ex:1: anonymous fn/1 in MyApp.Accounts.User.__verify_ash_dsl__/1
        (elixir 1.14.1) lib/enum.ex:975: Enum."-each/2-lists^foreach/1-0-"/2
        lib/MyApp/accounts/resources/user.ex:1: MyApp.Accounts.User.__verify_ash_dsl__/1
        (elixir 1.14.1) lib/enum.ex:975: Enum."-each/2-lists^foreach/1-0-"/2
        (elixir 1.14.1) lib/module/parallel_checker.ex:239: Module.ParallelChecker.check_module/2
        (elixir 1.14.1) lib/module/parallel_checker.ex:78: anonymous fn/5 in Module.ParallelChecker.spawn/3

6 replies

AEAsh Elixir

•Created by Jason on 4/30/2023 in #support

Publish :create, ["created", deeply_nested_item_id]

Let's say my resources have this relationship, chat_room has many posts which then has many comments. and I want to have this pub_sub definedin comment.ex.

   pub_sub do
     ...
     publish :create, ["created", :chat_room_id]

   relationships do
     belongs_to :post, MyApp.Chat.Post do
       api MyApp.Chat
      ..

   aggregates do
     first  :chat_room_id, :post, :chat_room_id

   pub_sub do
     ...
     publish :create, ["created", :chat_room_id]

   relationships do
     belongs_to :post, MyApp.Chat.Post do
       api MyApp.Chat
      ..

   aggregates do
     first  :chat_room_id, :post, :chat_room_id

Unfortuantely, this gives me the following error. What's the right way to do this?

** (Protocol.UndefinedError) protocol String.Chars not implemented for #Ash.NotLoaded<:aggregate> of type Ash.NotLoaded (a struct)

** (Protocol.UndefinedError) protocol String.Chars not implemented for #Ash.NotLoaded<:aggregate> of type Ash.NotLoaded (a struct)

My chat_room_load() function that feeds the data to the form is defined like this.

def chat_room_load() do
  comments =
     Comment
     |> Ash.Query.load([:post, :chat_room_id])
  posts =
     Post
     |> Ash.Query.load([
        comment: comments
        ...
         ])

def chat_room_load() do
  comments =
     Comment
     |> Ash.Query.load([:post, :chat_room_id])
  posts =
     Post
     |> Ash.Query.load([
        comment: comments
        ...
         ])

16 replies

AEAsh Elixir

•Created by Jason on 4/25/2023 in #support

Nested form with filtered subform elements

Let's say there is a nested form with Tweet as the main and Comment as the sub. The requirement is to only show and make editable the comments entered by the current user in the subform. I'm hoping to accomplish this without using CSS tricks of hiding other users' comments. By loading filtered records into the form using the code below, I was able to make the form look like what I want, but when I submit the form, comments previously made by other users (apparently, filtered out from the form) seem to be removed. Is this the expected behavior of a nested form? Is there a relatively easy way to make it save the change without removing other users' comments?

  def tweet_load(current_user) do
    comments=
      Comment
      |> Ash.Query.filter(user_id == ^current_user.id)

    tweets=
      Tweet
      |> Ash.Query.sort(row_order: :asc)
      |> Ash.Query.load([     
        comments: comments
      ])

  def tweet_load(current_user) do
    comments=
      Comment
      |> Ash.Query.filter(user_id == ^current_user.id)

    tweets=
      Tweet
      |> Ash.Query.sort(row_order: :asc)
      |> Ash.Query.load([     
        comments: comments
      ])

14 replies

AEAsh Elixir

•Created by Jason on 4/24/2023 in #support

Not getting pub_sub notification

Trying pub_sub the first time using Ash, so I could be missing something very simple. The console shows a debug message like this, but the liveview handle_info isn't triggered. Do I need any other plumbing code than what's shown in the code excerpts below?

[debug] Broadcasting to topics ["items:update:bcb9b300-22b9-474e-8a8a-81473568e438"] via MyAppWeb.Endpoint.broadcast

Notification:

%Ash.Notifier.Notification{resource: ...

[debug] Broadcasting to topics ["items:update:bcb9b300-22b9-474e-8a8a-81473568e438"] via MyAppWeb.Endpoint.broadcast

Notification:

%Ash.Notifier.Notification{resource: ...

Here are the relevant codes currently in place. ``` <Liveview> @impl true def handle_info( %Phoenix.Socket.Broadcast{ topic: "items:update:" <> id }, socket ) do IO.inspect(id, "items:update id") ### This doesn't show up in the console. <Resource> pub_sub do module MyAppWeb.Endpoint prefix "items" broadcast_type :phoenix_broadcast publish :update, ["update", :id] end update :update do accept [ :name ] end ...

3 replies

AEAsh Elixir

•Created by Jason on 4/19/2023 in #support

Refresh "calculations" during form.validate

This question is kind of similar to https://discordapp.com/channels/711271361523351632/1071883200378445854/1071883200378445854 However, that example is a simple calculation involving two of the readily available form fields, whereas mine isn't as simple in that one of the inputs needs an aggregation of counts from an embedded array field as shown below. I want to be able to display the remaining count of an item which would decrease as the user increases the usage count.

calculate :item_remaining_count,
              :integer,
              MyApp.Calculations.ActionCountsHelpers

calculate :item_remaining_count,
              :integer,
              MyApp.Calculations.ActionCountsHelpers

defmodule MyApp.Calculations.ActionCountsHelpers do
  use Ash.Calculation

  @impl true
  def calculate(records, opts, params) do
    Enum.map(records, fn record ->
      ActionCountHelpers.item_remaining_count(records) ## << Error happens here.
    end)
  end
end

  def sum_usage_count(%Item{} = item) do
    if item.usage_embeds do
      Enum.reduce(item.usage_embeds , 0, fn cnt, acc -> acc + cnt.usage_count end)

    else
      0
    end
  end

  def item_remaining_count(%Item{} = item) do
    item.item_count - sum_usage_count(item)
  end

defmodule MyApp.Calculations.ActionCountsHelpers do
  use Ash.Calculation

  @impl true
  def calculate(records, opts, params) do
    Enum.map(records, fn record ->
      ActionCountHelpers.item_remaining_count(records) ## << Error happens here.
    end)
  end
end

  def sum_usage_count(%Item{} = item) do
    if item.usage_embeds do
      Enum.reduce(item.usage_embeds , 0, fn cnt, acc -> acc + cnt.usage_count end)

    else
      0
    end
  end

  def item_remaining_count(%Item{} = item) do
    item.item_count - sum_usage_count(item)
  end

I'm not sure how to initiate the re-calculation, but here is what I tried.

  def handle_event("validate", %{"form" => form_params} = params, socket) do

    form = AshPhoenix.Form.validate(socket.assigns.form, form_params)
    MyApp.Projects.Item.item_remaining_count() # <<<
    
    {:noreply, assign(socket, form: form)}
  end

  def handle_event("validate", %{"form" => form_params} = params, socket) do

    form = AshPhoenix.Form.validate(socket.assigns.form, form_params)
    MyApp.Projects.Item.item_remaining_count() # <<<
    
    {:noreply, assign(socket, form: form)}
  end

5 replies

AEAsh Elixir

•Created by Jason on 4/14/2023 in #support

Re-sort items in a form without submitting the form

Let's say I have a form to input a lit of to-do items, and want to give the user up/down buttons to reorder them based on priority. I can probably change the priority value via phx-click event, but I'm not sure what's the best way to display the items reordered based on the new priority values, without submitting the form. I'm guessing it should be done in the 'validate' handle_event, which currently only includes this.

form = AshPhoenix.Form.validate(socket.assigns.form, form_params)

form = AshPhoenix.Form.validate(socket.assigns.form, form_params)

30 replies

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