How do I create a button or a link to download a specific file?

I have determined a method that will get the download parameter of a link_to() , so that it would serve several types. To follow this example I have a file called: javascript_the_good_parts.pdf located in / public / .

Create a controller called Pages (app / controllers / pages_controller.rb):

class PagesController < ApplicationController
  def index    
  end
  def download
    send_file "#{Rails.root}/public/#{params[:file_name]}"
  end
end

Add in your routes (config / routes.rb):

root 'pages#index'
get 'download'=> 'pages#download'

And as page (app / views / pages / index.html):

<%= link_to "Fazer Dowload" ,:action => :download, :file_name => "javascript_the_good_parts.pdf" %>

Screenshot Example:

You can treat your file with a different driver if you do not want to handle the HTTP server settings.

For this you could use send_file

There is the download attribute in HTML5 that can be used like this:

<a href="/images/myw3schoolsimage.jpg" download>

First you have to put a iframe hidden and without src in your application

<iframe name="iframe_download" class="hidden"></iframe>

Now you can put the download link with the target to the hidden iframe

<a href="/caminho/para/download.pdf" target="iframe_download">Clique para baixar</a>

I hope I have helped