Validating nested params

[hanami]

Validating nested params

[jodosha]

@mattbeedle Thanks for mentioning this idea. Our goal is to release a new version of Lotus in a month, so the deadline is really close and we can't have a look to this in the near future.

Have you tried to flatten the params to one level and let the lower components to separate those attributes?

[jodosha]

@mattbeedle @joneslee85 Most of the times we have single level of attributes, but grouped per entity.

Given the following form:

<form action="/books" method="POST">
  <input type="text" name="book[title]" />
</form>

The raw Hash of params that comes from the Rack env is { "book" => { "title" => "Refactoring" } }.
It doesn't work well with the actual implementation of Action.params which only understands top level params.

Instead of having nested blocks, which adds complexity both in Action and in Validations, what if we introduce an optional param name like this:

params :book do
  param :title # ...
end

If present it will extract and consider only that part of the Rack input.
What do you think?

[stevehodgkiss]

It is possible to use Virtus for nested attributes. You'd probably need to use another validation library in the Job class though.

class Job
  include Virtus.model(strict: true)

  attribute :title, String, required: false
end

# action
params do
  param :job, type: Job
end

@jodosha I can imagine a lot of scenarios where you'd still need to access other top level parameters... for example a route parameter /jobs/:id.

[jodosha]

@stevehodgkiss We use Lotus::Validations for the purpose. I would love to include nested capability there.

[jodosha]

Resolved by #71