[dry-validation] how to write rules for nested array of hashes

Support dry-validation
1

How does one apply rules to nested arrays of hashes? Toy example:

class MyContract < Dry::Validation::Contract
  schema do
    required(:stores).array(:hash) do
      required(:products).array(:hash) do
        required(:name).filled(:string)
      end
    end
  end
end

What is the right way to apply validation to all the product names (specifically, stores[i][:products][j][:name])? The only thing I can come up with uses nested loops and is really ugly.

Basically, my goal would be something like this:

rule("stores.products.name") do
  key.failure("is not valid") unless validate(name)
end
1 Like
2

You can write your rule as follows:

rule(:stores).each do
    value[:products].each_with_index do |product, index|
      name_key = key(key.path.keys + [:product, index])
      name_key.failure('must have a name') unless validate(product[:name])
    end
  end

Hope it helps

1 Like
3

I tried something like that, but tbh it feels like a hack. And I actually have a more deeply nested structure I need to validate. For example:

class MyContract < Dry::Validation::Contract
  schema do
    required(:stores).array(:hash) do
      required(:products).array(:hash) do
        required(:sizes).array(:hash) do
          required(:text).filled(:integer)
        end
      end
    end
  end
end

With something like this, I think Iā€™d need nested loops in the rule, which starts to get tedious.

4

This is not yet supported by each but the goal is to eventually be able to write something like rule("stores[].products[].sizes[]").each { .... } that would trigger the rule for each element in the sizes array that passed schema checks.

1 Like
5

Wow, that would be great syntax! Looking forward to it. Thanks for the info.

1 Like