Rails 4 Method Not Allowed after Upgrading from Rails 3

It turns out the problem was with the name 'assets' I can't find any documentation to confirm this, but renaming the asset model and controller to something else fixed the problem.

This isn't just about the word assets. Rails does not like when a route path and the asset directory are in the same subdirectory.

When making a post request, you will get method not allowed. The problem is there can be no overlap with paths and the asset directory. The problem is specifically with POST requests in that path. I am assuming somewhere in rails, they must have disabled all non-GET requests for the assets directory.

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In this very simple app below, you will get a method not allowed error. Because the path /welcomes is being used for a route and for an asset prefix.

File: config/environment/development.rb

config.assets.prefix = '/welcomes'

File: config/routes.rb

resources :welcomes, path: 'welcomes', only: ['index', 'create']

File: app/controllers/welcomes_controller.rb

class WelcomesController < ApplicationController
  def index
    @welcome = 'hello';
  end

  def create
    @welcome = 'world';
  end
end

File: app/views/welcomes/index.html.rb

<%= form_for(@welcome) do |f| %>
    <%= f.submit 'Submit' %>
<% end %>

File: app/views/welcomes/create.html.rb

<h1>Welcomes#create</h1>
<p>Find me in app/views/welcomes/create.html.erb</p>