2 field validation in Hanami + dry-validation

Question

I've been trying to validate a sign in process using Hanami (which is on top of dry-validation).

The point is: how to validate someting related to 2 fields: email + password?

I've read about custom predicates, but they seem to be only per field. Another concept is rule, but according to the examples it doesn't relate 2 things the way I need.

Here is my code:

module Web::Controllers::Sessions
  class Create
    include Web::Action

    expose :validation # my standard way to show errors in the template

    def call(params)
      @validation = SigninValidator.new(params[:user]).validate
      if @validation.success? 
      # more stuff here
    end
  end
end

class SigninValidator
  include Hanami::Validations::Form

  validations do
    required(:email) { format?(EMAIL_REGEX)}
    required(:password).filled(:str?)

    # I GOT CONFUSED HERE
    # how could I use someting like a repository and relate something like 
    # predicate + message for "email or password doesn't match"

  end
end

Unfortunately the validations section in Hanami Guide is empty and I couldn't find a solution looking at the sources (hanami-validation and dry-validation).

Any help would be appreciated.

score 3 · Answer 1 · answered Jun 13 '17 at 17:05

You can use either High-Level Rules or Custom Validation Blocks. Something like this:

validations do
  required(:email) { format?(EMAIL_REGEX)}
  required(:password).filled(:str?)

  rule(:email_and_password: [:email, :password]) do |email, password|
    # Example, do what you need here
    # Only dry-rb rules are valid here
    email.filled? & password.filled?
  end

  # Or

  validate(:email_and_password: [:email, :password]) do |email, password|
    # Example, do what you need here
    # Any Ruby code is valid here
    email.filled? && password.filled?
  end
end

Maybe you will need to set :email and :password to optional here, and ensure they're filled inside rule or validate block.

Hey, Diego! Also, as you said you want to validate against an external dependency (repository) it would be a good idea take a look on this http://dry-rb.org/gems/dry-validation/basics/working-with-schemas/ See the `option` inside the `configure` block. The `option` combined with the `validate` mentioned by @m45t3r should do the trick! — Kleber S., Jun 13 '17 at 17:14

score 0 · Answer 2 · answered Jun 05 '19 at 10:55

I don't fully understand what you're trying to achieve, it seems as though you're attempting to validate whether the email and/or password match the ones in your database? If so then you're doing it in the wrong place, validators are intended to validate the params only. So if the email is in the wrong format, or the password and password confirmation don't match, a validation can catch that and provide the right error message. If you're looking to verify details against the database then this is something that should be done in the interactor.

m45t3r is correct in saying that if you do want to validate two dependent attributes then a rule is probably the way to go.

As for your broken link, the Hanami guides got moved a while back and the old links don't seem to have been forwarded too well! The current docs for validations, and specifically rules, can be found here.

2 field validation in Hanami + dry-validation

2 Answers2