How to access nested attributes in ruby on rails?

Question

I want to access usr_additional_users_attributes in the following params? how can i do that ?

 params.require(:usr_contact).permit(:first_name, :last_name, :dob, :gender,
                                    :mobile, :email, :password,
                                    :password_confirmation,
                                    :image,
                                    usr_contact_vendors_attributes:
                                        [:id, usr_vendor_property_attributes:
                                            [:shop_name, :specified_area, :mobile, :website,
                                             usr_vendor_branches_attributes:
                                                 [:address_line1, :address_line2, :city ,:zip_code ],
                                             usr_additional_users_attributes:[:id,:email,:role, :_destroy]]] )

end

I want to get it like this in my controller and put emails to an array. this one showing an error

 params[:usr_contact][:usr_contact_vendors_attributes][:usr_vendor_property_attributes][:usr_additional_users_attributes].values.each do |item|
      @emailSet << item[:email]
    end

undefined method `[]' for nil:NilClass

any suggestions ?

I would say, go step by step to check params[:usr_contact], then params[:usr_contact][:usr_contact_vendors_attributes], and so on. One of these is nil. — Jagdeep Singh
– Jagdeep Singh, Commented May 3, 2017 at 8:34

Community · Accepted Answer · 2017-05-23 12:18:08Z

2

You would have to use dig because when you're trying to access one of these params, they're null, so Ruby raise this exception. By using dig, it's like it's checking every attribute before you're accessing it. It would be good to check inside the item too with item[:email].present?

Your code would look like:

 params.dig(:usr_contact, :usr_contact_vendors_attributes, :usr_vendor_property_attributes, :usr_additional_users_attributes).values.each do |item|
   @emailSet << item[:email] if item[:email].present?
 end

edited May 23, 2017 at 12:18

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answered May 3, 2017 at 11:50

diofeher

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Comments

Chetan Mehta · Accepted Answer · 2017-05-03 06:28:38Z

I have an example of how I did it in my scenario:

def patient_params
    params.require(:patient).permit(*permited_patient_attributes)
  end

  def permited_patient_attributes
    [
      :user_id,
      :start,
      patient_demographic_attributes: [
        :id,
        :patient_id,
        :start_date,
        :end_date,
        :first_name,
        :middle_name,
        :last_name,
        :date_of_birth,
        :gender,
        :ethnicity,
        :marital_status],
      patient_contact_attributes: [
        :id,
        :patient_id,
        :street_address,
        :extended_address,
        :locality,
        :region,
        :postal_code,
        :country],
      patient_email_attributes: [
        :id,
        :email],
      patient_mrn_attributes: [
        :id,
        :patient_id,
        :mrn],
      contact_telephones_attributes: [
        :id,
        :party_type,
        :party_id,
        :name,
        :number,
        :_destroy],
      patient_physicians_attributes: [
        :id,
        :patient_id,
        physician_id: []]
    ]
  end

Here patient_demographic_attributes, patient_contact_attributes. are nested one.Have a try

omarshariffd · Accepted Answer · 2017-05-03 08:35:18Z

0

You need to make sure that your item is not nil before pushing it to your array. Easiest way is to do this is by adding a check if item is nil.

@emailSet << item[:email] unless item.nil?

answered May 3, 2017 at 8:35

omarshariffd

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Comments

Chanaka · Accepted Answer · 2017-05-05 10:23:42Z

0

I fixed it by printing params. It was something like this

{"0"=>{"usr_vendor_property_attributes"=>{"shop_name"=>"cbhcvbcvb", "specified_area"=>"cbcvbcb", "website"=>"[email protected]", "mobile"=>"3543243", "usr_vendor_branches_attributes"=>{"1493800739760"=>{"address_line1"=>"", "address_line2"=>"", "city"=>"", "zip_code"=>""}}, "usr_additional_users_attributes"=>{"1493800739774"=>{"email"=>"sdgdfgd", "role"=>"Role1", "_destroy"=>"false"}}}}} permitted: false>

I have miss that ["0"], that was the issue. Then params can access in the controller like this.

 @test = params[:usr_contact][:usr_contact_vendors_attributes]["0"][:usr_vendor_property_attributes][:usr_additional_users_attributes]

Thanks for helping :D

answered May 5, 2017 at 10:23

Chanaka

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1 Comment

helenatxu Over a year ago

Yes, but if one of the params in the middle is nil, it will raise an error.

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