ParameterMissing - 参数缺失或值为空：user

Question

I need to change the user type. Doing through STI.

Clicking the link passes the parameter :type.

My models:

class User < ApplicationRecord
class Admin < User
class Seller < User
class Guest < User

Views

tbody
    - @users.each do |user|
      tr 
        td = user.email
        td = user.type
        td = link_to "admin", edit_user_path(user, type: 'Admin')
        td = link_to "guest", edit_user_path(user, type: 'Guest')
        td = link_to "seller", edit_user_path(user, type: 'Seller')

routes.rb

  resources :users 
  resources :admins, controller: :users, :type => "Admin"
  resources :guests, controller: :users, :type => "Guest"
  resources :sellers, controller: :users, :type => "Seller"

Error

ActionController::ParameterMissing in UsersController#update
param is missing or the value is empty: user

Parameters:

{"_method"=>"patch", "authenticity_token"=>"56bC4iWSsYd+VrN7RV0NCMj4YD+fIMQKb8uKKC9dUkMtOORAilwPlk3oAgT2L8j5qMsH4tNdzy6zbdL5nVVi7Q==", "type"=>"Admin", "id"=>"3"}

controller

  def update
    if current_admin
      if @user.update(user_params)
        redirect_to users_path
      else
        render 'edit'
      end
    end
  end

  private
  def user_params
    params.require(:user).permit(:type)
  end

Why this error? action expects that one parameter :the user, but it is not?

Answer 1

require ensures that a parameter is present. If it's present, returns the parameter at the given key, otherwise raises an ActionController::ParameterMissing error .

You are requiring user parameter but it's missing from the params.

To get this you have many ways.

Method 1:

Removing require should do the trick.

params.permit(:type)

Method2:

Add a user[] as a name to the input in the edit form.

Will elaborate the method 1 if you add the edit form.

Method3:

The other solution is to add the user key to the parameters.

def update
    if current_admin
        params.user = {
            "type": params.type,
            "id": params.id
        }
      if @user.update(user_params)
        redirect_to users_path
      else
        render 'edit'
      end
    end
  end

  private
  def user_params
    params.require(:user).permit(:type)
  end

reference to api documentaiton