Unpermitted parameter in Rails 5

Question

First of all, I want to just get the object inside the current object, which I send to my back-end .

I have this simple JSON (generated from a form):

 { "name": "Project 1", "project_criteria": [ { "name": "Criterium 1", "type": "Type 1", "benefit": "1" }, { "name": "Criterium 2", "type": "Type 2", "benefit": "3" } ] } 

My classes :

 class Project < ApplicationRecord has_many :project_criteria accepts_nested_attributes_for :project_criteria end class ProjectCriterium < ApplicationRecord belongs_to :project end 

ProjectsController:

 def project_params params.require(:project).permit(:name, project_criteria: [] ) end 

But I still cannot access the project_criteria parameter, as you can see below:

 Started POST "/projects" for 127.0.0.1 at 2016-08-19 16:24:03 -0300 Processing by ProjectsController#create as HTML Parameters: {"project"=>{"name"=>"Project 1", "project_criteria"=>{"0"=>{"benefit"=>"1", "name"=>"Criterium 1", "type"=>"Type 1"}, "1"=>{"benefit"=>"3", "name"=>"Criterium 2", "type"=>"Type 2"}}}} Unpermitted parameter: project_criteria # <----------- 

Note:

By the way, I already tried to use the criterion instead of the criteria (which , in my opinion, is correct, since it should be pluralized) in has_many and accepts_nested_attributes_for , but it also does not work.

Does anyone have a solution for this?

Answer 1

This is not an inflection of the word “criteria” that gives you problems (although you can add a custom inflector to get the unique and multiple versions that you prefer if you want).

The problem is that you must explicitly allow fields of nested objects.

Change the current settings:

 params.require(:project).permit(:name, project_criteria: [] ) 

To this (for one nested object):

 params.require(:project).permit(:name, project_criteria: [:name, :type, :benefit] ) 

Your business is somewhat compounded by the fact that you are dealing with several nested objects, so you have to pass the hash instead:

 params.require(:project).permit(:name, { project_criteria: [:name, :type, :benefit]} )