Handle has_many nested forms

[paulcsmith]

class TaskForm < Task::BaseForm
  allow title
end

class TaskListForm < TaskList::BaseForm
  allow title
  has_many task_forms : TaskForm
end

# Use in an action
TaskListForm.create(params) do |task_list, form|
  # Handle like a normal form
end

# In a page
text_input @task_list_form.title
@task_list_form.task_forms.each do |task_form|
  text_input task_form.title
end

Some ideas for implementation

I think that a good starting point would be adding many_nested and many_nested? to LuckyRecord::Paramable Basically this would just be an abstract def that would need to then be implemented by LuckyRecord::Params.

Then you'd need to go the lucky repo and implement many_nested in Lucky::Params. For that it should:

• Look for form params in this format: form_name:field_name[position]. Example: tasks:title[0] would be the title for the first task. tasks:body[0] would be the body for the first task. Get it with params.many_nested(:task)
• JSON is much easier. It looks for an array under the given form name. E.g. params.many_nested(:tasks) gets {tasks: [{title: "title", body: "body"}]}
• It treats all JSON fields as string. So: {users: [{age: 30}]} would return [{"age" => "30"}] in Crystal

Prior art

• https://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html
• https://www.pluralsight.com/guides/ruby-on-rails-nested-attributes

[paulcsmith]

This one also might be really tricky, but if someone wants to give it a go I'd be grateful!

[repomaa]

see https://github.com/luckyframework/lucky/pull/681

[repomaa]

I'm not quite sure what the implementation of many_nested in https://github.com/luckyframework/lucky_record/blob/topic/many_nested/src/lucky_record/params.cr should look like...

[jkthorne]

I am curious in a resolution to this

[jwoertink]

There's already a PR https://github.com/luckyframework/avram/pull/53 I think it just needs to be revisited.

[paulcsmith]

Unfortunately that PR only adds the method for accessing the params, but then you'd still need a ton of logic for handling it in the operation :(

@wontruefree this will definitely be done, but it requires quite a lot of work and handling of many edge-cases. Also needs to be flexible enough that you can use it for the varying ways people might use it. 😅 I've got some ideas for how this will work, but I need to find time to just sit down and focus as it will require a lot of work

[jkthorne]

Awesome thanks for the update.

[jkthorne]

Has anyone looked more into this?

[paulcsmith]

@wontruefree On the list of things to do. I just have a lot of things to do :P

[jwoertink]

Yeah, there's already that PR open for it. We just need to revisit it. Make sure it's up to date with master, and all that stuff.

[paulcsmith]

Unfortunately that PR is the tip of the iceberg :( Will require lots of work on the save operation to actually implement it :(