Errors.md

Error handling with ActiveFormObjects

By default, most ActiveFormObjects error will be very familiar to you. In order to stick to Rails spirit, we have decided to let ActiveRecord raise its own errors.

In other words, you won't be forced to handle your errors any differently compared to a standard Rails stack.

Since ActiveFormObjects uses ActiveModel, ActiveFormObjects errors are standard ActiveModel::Validation errors. They look very similar to an ActiveRecord::RecordInvalid error.

If you need more control over ActiveFormObjects errors, you may use the following method anywhere in your form code.

map_errors_to

class RegistrationForm < ActiveFormObjects::Base
  save do
    map_errors_to(:something) do
      OtherForm.new({}).save!
    end
  end
end

This will allow you to scope errors coming from other models or classes to your parent form. The use cases we use it for is the following

class CustomForm < ActiveFormObjects::Base
  set_default value: {}, to: [:retailer, :program, :user_program]

save do
    map_errors_to(:retailer)     { @retailer = RetailerForm.new(@retailer).save! }
    map_errors_to(:program)      { @program  = ProgramForm.new(@program.merge(retailer: @retailer)).save! }
    map_errors_to(:user_program) { @resource = UserProgramForm.new(@user_program.merge(entity: @program, user: @user), @resource).save! }
  end
end

When an error is raised by RetailerForm or ProgramForm, map_errors_to will change ActiveRecord error hash from this :

{
  "name": ["name is mandatory"],
  "value": ["barcode value must be valid"]
}

to this :

{
  "retailer": {
    "name": ["name is mandatory"]
  },
  "user_program": {
    "value": ["barcode value must be valid"]
  }
}

allowing us to give the user a much more detailed feedback on where the error comes from.