序列化器嵌套关联仅包含某些属性

Question

My serializer looks like this:

class RegistrationSerializer < ActiveModel::Serializer
 attributes :id, :status
 has_one :student
 has_one :professor
 has_one :course
end

Instead of returning all of the student data, I would like to do something like this:

class RegistrationSerializer < ActiveModel::Serializer
 attributes :id, :status
 has_one :student [//only include :first_name]
 has_one :professor
 has_one :course
end

I dont want to edit student serializer directly because in other cases I will need all of the data.

Answer 1

You can accomplish this by also specifying a serializer for student. Here is an example:

class RegistrationSerializer < ActiveModel::Serializer
 attributes :id, :status
 has_one :student, serializer: StudentSerializerFirstNameOnly
 has_one :professor
 has_one :course
end

class StudentSerializerFirstNameOnly < ActiveModel::Serializer
 attributes :first_name
end

An alternative would be to flatten the data and have the student first name as a top level attribute:

class RegistrationSerializer < ActiveModel::Serializer
 attributes :id, :status, :student_first_name
 has_one :professor
 has_one :course

 def student_first_name
   object.student.first_name
 end
end