无法通过Rail应用程序导出csv文件

Question

I am trying to export a csv file through a rail application. I have a previous application which imports the data from a csv file and shows it in the webpage. That application was fired from the url http://localhost:3000/ and it was working fine.

But now I am trying to get back the data shown in the webpage back to a csv file which I can download from the page.

Now I am not sure why I am facing the error. The localhost page is not working and server is running in a loop.

I think I have some problems with in the user.rb file in all.each do section.

Actually I want to add a csv file download link in the same page.

My code is as follows:-

I created my app name is names My app\\controllers\\users_controller.rb file is:

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

 @users= User.order(:name)
 respond_to do |format|
  format.html { redirect_to root_url }
  format.csv {send_data @users.to_csv}

 end

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

My app\\models\\user.rb file is:

class User < ActiveRecord::Base
require 'csv'

def self.to_csv(options = {}) 
CSV.generate(headers: true) do |csv|
    csv << column_names
      all.each do |name|
        csv << name.attributes.values_at(*column_names)
      end
end
end




def self.import(file)
quote_chars = %w(" | ~ ^ & *)
begin
    CSV.foreach(file.path, headers: :first_row, quote_char:     quote_chars.shift) do |row|
    User.create! row.to_hash
end

rescue CSV::MalformedCSVError
    quote_chars.empty? ? raise : retry 
 end
end
end

My app\\views\\users\\index.html.erb file is:

<%= flash[:notice] %>

<p>
Download:
<%= link_to "CSV", names_path(format: "csv") %> |

</p>

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

<tbody>
    <% @users.each do |user| %>
    <tr>
        <td><%= user.age %></td>
        <td><%= user.name %></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 previous application database screenshot is:-

Answer 1

You are not following Rails conventions. You defined name controller, model and view but you didn't define routes for them. Something like resources :names or just for index action get '/names' => 'names#index' On the other hand you have routes defined for user, with resources :users, so you need to have UsersController(if you have defined users_controller check file name for it, this error may happen if you mistyped name for it).