Rails: NoMethodError - undefined method `record_type`

Question

I am working on a Rails 6 API only application using jsonapi-serializer gem.

I am using namespaces for the resources in my application, I also used namespaces for the serializer files.

So my serializer file looks like this:

module Applyportal
  class ApplicantSerializer
    include JSONAPI::Serializer
    attributes :first_name, :middle_name, :last_name, :phone, :email, :username, :password,  :nationality, :state_of_origin, :local_government

    belongs_to :local_government, serializer: Personalinfo::LocalGovernment
    belongs_to :marital_status, serializer: Personalinfo::MaritalStatus
    belongs_to :nationality, serializer: Personalinfo::Nationality
    has_many :applications, serializer: Applyportal::Application
    cache_options store: Rails.cache, namespace: 'jsonapi-serializer', expires_in: 1.hour
  end
end

But when I try to make a Post request to this resource I get the error below:

NoMethodError (undefined method `record_type' for #<Class:0x00007f05d4d451f8>
Did you mean?  record_timestamps)

I can't seem to figure out what the issue is.

Answer 1

The issue was coming from how I defined my serializer associations

Here's how I solved it:

So I used namespaces for the resources in my application, I also used namespaces for the serializer files.

So my serializer file looked like this:

module Applyportal
  class ApplicantSerializer
    include JSONAPI::Serializer
    attributes :first_name, :middle_name, :last_name, :phone, :email, :username, :password,  :nationality, :state_of_origin, :local_government

    belongs_to :local_government, serializer: Personalinfo::LocalGovernment
    belongs_to :marital_status, serializer: Personalinfo::MaritalStatus
    belongs_to :nationality, serializer: Personalinfo::Nationality
    has_many :applications, serializer: Applyportal::Application
    cache_options store: Rails.cache, namespace: 'jsonapi-serializer', expires_in: 1.hour
  end
end

I was missing to add Serializer at the end of each association which was making it difficult for the rails application to find the record_type, so instead of:

belongs_to :local_government, serializer: Personalinfo::LocalGovernment

it should be

belongs_to :local_government, serializer: Personalinfo::LocalGovernmentSerializer

So my serializer file looked like this afterwards:

module Applyportal
  class ApplicantSerializer
    include JSONAPI::Serializer
    attributes :first_name, :middle_name, :last_name, :phone, :email, :username, :password,  :nationality, :state_of_origin, :local_government

    belongs_to :local_government, serializer: Personalinfo::LocalGovernmentSerializer
    belongs_to :marital_status, serializer: Personalinfo::MaritalStatusSerializer
    belongs_to :nationality, serializer: Personalinfo::NationalitySerializer
    has_many :applications, serializer: Applyportal::ApplicationSerializer
    cache_options store: Rails.cache, namespace: 'jsonapi-serializer', expires_in: 1.hour
  end
end

That's all.

I hope this helps