I am not sure that this is specific to ash_phoenix, but that’s what I am using
ash_phoenix makes it pretty easy to build nested forms, but things get ugly pretty fast when some logic or non-standard controls appear in the form.
I have 3 resources: EntityType, Entity and Account. Entity belongs to EntityType, and Account belongs to EntityType optionally (entity_type_id in Account can be null).
I need to build a form that creates a resource call Template:
defmodule F0nance.Templates.TemplateEntry do
use Ash.Resource, data_layer: :embedded
actions do
defaults [:read, :destroy, create: :*, update: :*]
end
attributes do
uuid_v7_primary_key :id
attribute :debet_entity_param, :uuid_v7, allow_nil?: true
attribute :credit_entity_param, :uuid_v7, allow_nil?: true
end
relationships do
belongs_to :debet, F0nance.Accounts.Account, allow_nil?: false, public?: true
belongs_to :debet_entity, F0nance.Accounts.Entity, allow_nil?: true, public?: true
belongs_to :credit, F0nance.Accounts.Account, allow_nil?: false, public?: true
belongs_to :credit_entity, F0nance.Accounts.Entity, allow_nil?: true, public?: true
end
end
defmodule F0nance.Templates.TemplateParam do
use Ash.Resource, data_layer: :embedded
actions do
defaults [:read, :destroy, create: :*, update: :*]
end
validations do
validate present(:entity_type_id) do
where attribute_equals(:type, :entity)
end
end
attributes do
uuid_v7_primary_key :id
attribute :name, :string, allow_nil?: false, public?: true
attribute :type, :atom, allow_nil?: false, constraints: [one_of: [:entity]], public?: true
end
relationships do
belongs_to :entity_type, F0nance.Accounts.EntityType, allow_nil?: true, public?: true
end
end
defmodule F0nance.Templates.Template do
alias F0nance.Templates.TemplateEntry
alias F0nance.Templates.TemplateParam
use Ash.Resource, domain: F0nance.Templates, data_layer: AshPostgres.DataLayer
postgres do
table "templates"
repo F0nance.Repo
end
actions do
defaults [:read]
create :create do
primary? true
accept [:name, :description, :entries, :params]
end
end
attributes do
uuid_v7_primary_key :id
attribute :name, :ci_string, allow_nil?: false
attribute :description, :string
attribute :params, {:array, TemplateParam}, allow_nil?: false, default: []
attribute :entries, {:array, TemplateEntry}, allow_nil?: false, default: []
create_timestamp :created_at
update_timestamp :updated_at
end
identities do
identity :name, [:name], message: "Template names must be unique"
end
end
And this is the current prototype
One thing is that complicates things is that I am using a custom-built combo box to search for different related items (for example, accounts or entity types), and since the form only has ID of the resource that is selected, I need to make a database query to find the name. And since there is no way to put this into the form struct, I need to put it to a separate assign, and the fact that the form is nested makes the code too verbose. Another thing is that there will be more param types besides Entity, so I will need conditional display of other controls in place of Entity type. Again, the template becomes too verbose.
In journal entries sections, I also need to check if account belongs to an entity type, and if it does, I need to display a select with options listing all the params with “entity” type, and an additional option saying “fixed entity”. And again, if that “fixed entity” option is selected, an additional control has to be added to select an entity.
What I am doing is on form change I go through the nested forms and collect information about which resources need to be loaded ( “Participants” entity type and “Expenses” account in the example above) , and also generate the select options.
I think I will have to traverse the nested forms and collect and reorganize data in any case. But for the template, probably I could make a bunch of components and move all that conditional logic into the components’ modules. It’s just trading one complexity for another, but at least the HTML would be cleaner and easier to read
How do you approach similar problems?
