I am facing the routing error in rails as uninitialized constant UserController

Question

I am going create a rail application which takes input from an csv file and show it on the webpage.

After doing all the needful stuffs I am facing this: Routing Error

uninitialized constant UserController

My app\controllers\users_controller.rb file is:-

class UsersController < ApplicationController
   def index
    @users=User.all
   end

   def import
    User.import(params[:file])
    redirect_to root_url, notice: "Activity data imported!"
   end
end

My app\model\user.rb file is:- class User < ActiveRecord::Base require 'csv'

  def self.import(file)
    CSV.foreach(file.path, headers:true) do |row|
        User.create! row.to_hash
    end
  end
end

My app/views/users/index.html.erb file is:-

 <%= flash[:notice] %>

 <table>
 <thead>
    <tr>
        <th>Name</th>
        <th>Name</th>
    </tr>
 </thead>

<tbody>
    <% @users.each do |user| %>
    <tr>
        <td><%= user.user %></td>
        <td><%= user.age %></td>
    </tr>
    <% end %>
</tbody>
</table>

<div>
<h4>Import the data!</h4>
<%= form_tag import_users_path, multipart: true do %>
<%= file_field_tag :file %>
<%= submit_tag "Import CSV" %>
<% end %>
</div>

My config\routes.rb file is:-

Rails.application.routes.draw do
get 'users/index'

get 'users/import'

resources :users do
 collection {post :import}
end
root to: "user#index"
end

I have not posted any #marked commented line from routes.rb file here. The snapshot of the output screen is here:- when clicking on the import csv button the following error is shown:

Answer 1

You just have a mismatch in the pluralization of UsersController vs UserController. The convention in Rails is to use plural for controller names.

Change the line in your routes.rb file to:

root to: "users#index"

Answer 2

Change controller file from app\controllers\users_controller.rb to app\controllers\user_controller.rb

Answer 3

As per the error the problem is Routing error so check the route.rb file and as per the above answers you need to change the line

root to: "user#index"

to

root to: "users#index"

in the config\routes.rb file.