Extension to validate?

[SkyCrawl]

Would there be an easy way to add validations to certain declared properties or hash keys?

For example:

class Mine < ::Hashie::Dash
    include ::Hashie::Extensions::MethodAccess
    include ::Hashie::Extensions::MethodValidation

    property :title, required: true, validated: true

    def title_valid?(value)
      ...
    end
end

Perhaps even:

class Mine < ::Hashie::Dash
    include ::Hashie::Extensions::MethodAccess
    include ::Hashie::Extensions::MethodValidation

    property :title, required: true, validated_common: true

    def property_valid?(name, value)
      ...
    end
end

[michaelherold]

What types of things would you want to validate? Type "validations" can be done using the property translation mixin (i.e. the behavior that Trash adds to Dash).

[SkyCrawl]

Specifically, I'd like the hash classes to provide a mechanism for validating semantics (values). Using the above example:

def title_valid?(value)
    value.length < 16
end

def property_valid?(name, value)
      false if value.nil?
      value =~ /email_regex/ if name.start_with?('email-')
      ...
end

It'd be great to know that (e.g.) Dash refuses to accept (whether silently or with error - depending on what the user wants) entries that have a value of nil :).

[martinstreicher]

I have been doing this to get validations:

      include ActiveModel::Validations

[dblock]

I think @martinstreicher is onto something, ActiveModel is the "golden standard" and just works out of the box. Any reason why we would still want this here?

[martinstreicher]

This is a code snippet from a class derived from Hashie.

require 'hashie/dash'

module DSL
  module Keywords
    class Base < Hashie::Dash
      include ActiveModel::Validations

I can then do things like validate :method and valid? There is some overlap with things like Hashie::Dash require and validates_presence_of, but I can use all the rest of the common validators, plus write any of my own.

[dblock]

I wonder whether we should add this to the docs, what do you think @martinstreicher ?

[martinstreicher]

I think it worthwhile. In my recent use cases, I am using Hashie::Dash as a stand-in for ActiveModel where I don’t require persistence. I use the other features of Hashie like coercion and dot access and mix in ActiveModel components to do validation, etc.

On Aug 22, 2015, at 3:43 PM, Daniel Doubrovkine (dB.) @dblockdotorg notifications@github.com wrote:

I wonder whether we should add this to the docs, what do you think @martinstreicher ?

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[dblock]

I'm looking forward to a PR from @martinstreicher :)