Rails getting started 5.7 - ruby-on-rails

Question

I'm programming for the first time in ruby and so I'm doing the 'getting started' tutorial from the official website:
http://guides.rubyonrails.org/getting_started.html
I have a problem with 5.7. The tutorial says:
If you submit the form again now, Rails will complain about not
finding the show action. That's not very useful though, so let's add
the show action before proceeding.
And then there is the following code:
post GET /posts/:id(.:format) posts#show
But where do I have to put this code?
Thanks!

Answer 1

What you've depicted is the show member for the posts resource routes. It's not actually code, but rather, a pattern for URL routing. You can see all your routes in this fashion by typing rake routes from the command line.
Breaking down the route:
post GET /posts/:id(.:format) posts#show
# `post` => named route name (available by default only to singular routes)
# `GET` => HTTP method
# `/posts/:id(.:format)` => path made accessible by route
# :id => specifies that the argument passed in as `:id` is available to the controller as `params[:id]`
# `posts#show` => controller is `posts`, action is `show`
You need to create a corresponding show controller action that the route will map to:
# app/controllers/posts_controller.rb
def show
#post = Post.find(params[:id])
end

Answer 2

I just ran into this same problem going through the tutorial. A more direct response to this question is "no where". The reference to that line int the tutorial is only informational. It reads in a way that leads you to believe that you are supposed to add it but there is nothing to add. Just keep going through the rest of the tutorial and all will be well. Maybe someday the author will read this and fix it.

Answer 3

Adding the following (bolded) sentence would make the instructions in 5.7 more clear:
If you submit the form again now, Rails will complain about not finding the show action. That's not very useful though, so let's add the show action before proceeding. Running 'rake routes`now results in the following:
post GET /posts/:id(.:format) posts#show

Answer 4

If you have the PostsController in your application, then you must have the following in the config/routes.rb
resources :posts
So that it will generate 7 default routes for the posts controller where show is a default action.
When you do rake routes in your console, it will show you all the routes for your application. From those routes, you can get
post GET /posts/:id(.:format) posts#show
The above is the routes, not the code. So it states that you have a controller named "posts" and "show" is an action of it. Which can be accessible via '/posts/:id' with "get" method.

Answer 5

Make sure the private section comes after the def show block
class PostsController < ApplicationController
def new
end
def create
#render text: params[:post].inspect
#post = Post.new(post_params)
#post.save
redirect_to #post
end
def show
#post = Post.find(params[:id])
end
private
def post_params
params.require(:post).permit(:title, :text)
end
end

Answer 6

Nothing needs to be added to the config file, as some guys already said, is the information that appears after run the command
rake routes
Just adding the show action to the post_controller.rb and the show.html.erb view is enough to be able to post the information and continue with the example.