Adding attribute to object in jbuilder doesn't work

Question

While building a JSON response with jbuilder, I want to add an attribute "image_full_url" to each of my Employee objects.

In my jbuilder file this looks like follows:

json.branch_companies @companies.select{ |branch| branch.head_company_id == head_company.id}.map{|branch| {
    :branch => branch, 
    :employees => branch.employees.select(employee_attributes).each{ |emp| emp.image_full_url = "#{root_url[0..-2]}#{emp.photo_image.url}" },
    :machine_categories => branch.machine_categories.pluck(:id, :name, :description)
    }
}

In my Emplyoee Model I have a corresponding attr_accessor:

attr_accessor :image_full_url

Adding an attribute to an Employee object works perfectly on the console.

The part I having problems is here:

:employees => branch.employees.select(employee_attributes).each{ |emp| emp.image_full_url = "#{root_url[0..-2]}#{emp.photo_image.url}" }

I would expect that the "image_full_url" attribute was added to the emp object, but it isnn't. The JSON response doesn't contain the "image_full_path" field. What am I doing wrong? Can anyone help here?

Answer 1

Of course you will not get :image_full_url attribute in your json output, because serializer does know nothing about it. You can simply check this by doing next:

Emplyoee.limit(2).each{|e| e.image_full_url = "asdw"}.as_json

As a result, output won't contain :image_full_url attribute. If you want that attribute to be in your final result, add to that next line:

.as_json(:methods => [:image_full_url])