rails post path issue - ruby-on-rails

Question

I've an issue with the paths in the views and I don't know how to solve it.
I've "categories" that has_many "posts" and "posts" that belongs_to "categories".
1.- I want to show on home page the truncate last post of an specific category (the ID number "1"). Then I want that post to link to the show post path but I get this error:
"Unknow Action
The action 'index' could not be found for PostsController"
I think I've my paths wrong because I don't need the index view because I'm only going to show that specific post. So, I think that category_posts_path(#last_post) is not the right path (I don't know where to look for more info about making the route path in the views...). Actually, the browser is showing me that is looking for the "2" category when it is a post of the "1" category...? What am I doing wrong?
This is the browser route:
http://localhost:3000/en/categories/2/posts
This is my views/categories/home.html.erb file:
<div class="post_details">
<h2><%= #last_post.title %></h2>
<%= image_tag #last_post.image(:header), class: "post_image" %>
<p><%= truncate #last_post.body, length: 100 %></p>
<p class="button"><%= link_to "READ MORE", category_posts_path(#last_post) %></p>
</div>
2.- I have another path problem in the views/categories/show.html.erb file. I have a loop to show all the post of one specific category, but when I link in some post (to show it) there is the "index" error again:
"Unknow action
The action 'index' could not be found for PostsController"
This is the browser route:
http://localhost:3000/en/categories/1/posts
This is the views/categories/show.html.erb file:
<div class="post_details">
<h2><%= link_to post.title, category_posts_path(post) %></h2>
<%= image_tag post.image(:header), class: "post_image" %>
<p><%= post.body %></p>
</div>
This is the categories_controller.rb file:
class CategoriesController < ApplicationController
before_action :get_categories
def index
end
def show
#category = Category.find(params[:id])
end
def home
if params[:set_locale]
redirect_to root_url(locale: params[:set_locale])
else
#category = Category.find_by_id(1)
#last_post = #category.posts.order("created_at desc").first
end
end
def get_categories
#categories = Category.all.order("rank asc, name asc")
end
end
This is my posts_controller.rb file:
class PostsController < ApplicationController
def show
#category = Category.find(params[:category_id])
#post = #category.posts.find(params[:id])
end
end
This is my route.rb file:
scope '(:locale)' do
resources :categories do
resources :posts
end
resources :contacts
root 'categories#home'
get "/contact" => "contacts#new"
# static pages
get "/investment" => "contents#investment"
get "/partner-with-us" => "contents#partner", as: "partner"
get "/our-companies" => "contents#companies", as: "companies"
get "/site-map" => "contents#sitemap", as: "sitemap"
get "/terms-and-conditions" => "contents#terms", as: "terms"
get "/privacy" => "contents#privacy"
end

Answer 1

When you are nesting routes you should always consider what is the parent and whats a child in given route. Since your paths don't know anything about your associations you have to explicitly define every object in the nesting.
I.e. since you nested posts in categories linking to last post in given category would look like this:
category_post_path(#category, #last_post)
(I think you have also a typo there - category_posts_paths - which links to posts index index - hence the error. Use category_post_path. instead, and give it both parent category and the post.
You can run rake routes to see exact information on paths (or go to http://localhost:3000/rails/info/routes )