[With explanation of why to do it] How to prevent others from editing with Rails' CRUD app with authentication function

Introduction

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This time, I will explain the function that does not allow others to edit your own posts, which is common in CRUD apps with authentication function.

Premise

--Those who are familiar with crud apps --Those who are creating a simple Rails app --Those who are new to Rails or have a short period of time and are currently learning --Authentication settings and implementation of crud function have been completed with devise etc.

final goals

Implementation of a function to redirect to a list page etc. when the poster and editor are different when entering the URL to edit the post in solid

# post/1/Enter a URL such as edit
#If the poster and editor are different/Redirect to posts

① Make a method that always passes when trying to edit

"When you try to edit someone else's post, redirect it" means that when you try to edit, you must ** call that function **. First, let's create a situation where a certain process can be read when trying to edit or update.

posts_controller.rb

class PostssController < ApplicationController
  before_action :correct_user, only: [:edit, :update]

  #Omission

  def edit
    @book = Post.find(params[:id])
  end
end

before_action is explained in an easy-to-understand manner in this article. In other words, it always executes the specified method before the specified action.

This time, before edit and update… correct_user… that is, we are calling a method to check if we are the correct user.

② Define the method to be called

posts_controller.rb

#Omission
private
  def correct_user
    @post = Post.find(params[:id]) #Identify Post based on id
    @user = @post.user             #Identify the User associated with the identified Post and@Put in user
    if current_user != @user       #With the currently logged in user (editor)@If the user (poster) is different
      redirect_to posts_path       #Redirect to list page
    end
  end

As I wrote in the comment, it looks like this.

Since there were many articles that could be implemented by pasting this, I tried to summarize "why it happens". We hope for your reference.