Is there a way to return error code in addition to error message in rails active record validation?

Question

In rails activerecord validation, normally if a validation fails, it will add an error message in the errors attribute of models, however our clients demands an error code be returned in addition to error message, for example, we have a Bill model, which has a msisdn attribute, if msisdn is null, the error code is 101, if the msisdn doesn't complaint with MSISDN format, the error code is 102, when the client submits a request through REST interface, and if the validation fails, we should return a json object like

bill: {
    error_code: 101,
    error_message: "msisdn can't be null"
}

Is there a way to tell activerecord to generate an error code in addition to error messages? Thanks a lot.

Answer 1

Rails 5 will include a similar feature with foo.errors.details. You can easily use this to build better api errors.

class Person < ActiveRecord::Base
 validates :name, presence: true
end

person = Person.new
person.valid?
person.errors.details
# => {name: [{error: :blank}]}

If you prefer code errors as numbers, you can easily match numbers with the error keys.

For Rails 3 & 4 you can use this gem https://github.com/cowbell/active_model-errors_details witch is the exact same feature backported.