how to show article's content from another view - ruby-on-rails

Question

I was making a blog and I've got problem when I want to show an article
I've generate scaffold article title content:text and I just generate new controller called welcome with a view called homepage. I created new controller+view just to show articles. for this part I did not find the problem and then I created a new controller called post with a view called show is intended only to show the contents of the selected articles from the homepage.
how to show article's content from another view ?
I just added #article = Article.find(params[:id]) to post_controller
and then when I click an article's title in homepage I got error like this
Couldn't find Article with 'id'=
did I miss some code?
so this is my welcome_controller
class WelcomeController < ApplicationController
def homepage
#articles = Article.all
end
end
welcome/homepage.html.erb
<div class="post-preview">
<% #articles.each do |article|%>
<h2 class="post-title"><%= link_to article.title, welcome_show_path %></h2>
<%= truncate article.content, length: 160 %>
<hr>
<% end %>
</div>
post/show.html.erb
<div class="post-heading">
<h1><%= #article.title %></h1>
</div>
<div class="col-lg-8 col-lg-offset-2 col-md-10 col-md-offset-1">
<p><%= #article.content %></p>
</div>
post_controller
class PostController < ApplicationController
def show
#article = Article.find(params[:id])
end
end
routes.rb
Rails.application.routes.draw do
resources :articles
get 'welcome/homepage'
get 'post', to: 'post#show'
root 'welcome#homepage'
end
thanks :)

Answer 1

The problem seems to be in your link:
<h2 class="post-title"><%= link_to article.title, welcome_show_path %></h2>
welcome_show_path needs an id. Try welcome_show_path(id: article.id).
<h2 class="post-title"><%= link_to article.title, welcome_show_path(id: article.id) %></h2>
If that doesn't work, try: post_show_path(id: article.id).

Answer 2

You have 3 Controllers:
Article => generated by scaffolding, it means with predefined routes.
Welcome => only one method, called homepage
Post => only one method, called show.
Routes:
resources :articles ##generate default routes
get 'welcome/homepage' ##generate only one route, URL would be -> homepage_welcome_path.
get 'post', to: 'post#show' ##it will call show method without any parameter.
root 'welcome#homepage'
First:
get 'photos/:id', to: 'photos#show'
In your homepage.html.erb
<h2 class="post-title"><%= link_to article.title, welcome_show_path %></h2>
welcome_show_path ## expect show method in welcome controller, which is not exist.
Second:
To call show method of articles, you must pass ID of that article.
get 'articles/:id', to: 'articles#show' ##This route is already defined as you have `resource articles`. URL would be articles_path for the same.
Replace in homepage.html.erb
<h2 class="post-title"><%= link_to article.title, articles_path(id: article.id) %></h2>