Module: Dry::Transaction::Extra::Steps::Maybe::DSL

Defined in:
lib/dry/transaction/extra/steps/maybe.rb

Defined Under Namespace

Classes: NoValidatorError

Instance Method Summary collapse

Instance Method Details

#maybe(txn_or_container, key = nil, as: nil) ⇒ Object

Just like the ‘use` step, this invokes another transaction. However, it first checks to see if the transaction implements a `validator` method (usually provided by the validation_dsl extension), and if so, will call it before invoking the transaction.

If the validation succeeds, then it invokes the transaction as normal. If it fails, it continues on with the next step, passing the original input through.

step :create_user maybe VerifyEmail



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# File 'lib/dry/transaction/extra/steps/maybe.rb', line 27

def maybe(txn_or_container, key = nil, as: nil, **)
  if key
    container = txn_or_container
    method_name = as || :"#{container.name}.#{key}"
  else
    txn = txn_or_container
    method_name = as || txn.name.to_sym
  end

  merge(method_name, as:, **)
  define_method method_name do |*args|
    txn = container[key] if key
    txn_class = txn.is_a?(Class) ? txn : txn.class
    raise NoValidatorError, txn unless txn_class.respond_to? :validator

    result = txn_class.validator.new.call(*args)
    if result.failure?
      steps
        .detect { |step| step.name == method_name }
        .publish(:maybe_step_validation_failed,
                 step_name: method_name,
                 args:,
                 value: result)
      return Success(*args)
    end

    txn.call(*args)
  end
rescue NoMethodError => e
  raise e unless e.name == :name

  raise ArgumentError, "unable to determine step name from #{key_or_container}.\
      Pass an explicit step name using `as:` keyword argument."
end