Error trying to change database

Question

I'm following a tutorial to change the database depending on the subdomain, the subdomain must be the name of an existing database to which the system will connect as shown in this tutorial at 15:30 minute and works quite well, The problem comes when the system is accessed with a subdomain whose database does not exist, showing me the following error: Cannot open database "another_database" requested by the login. The login failed and displaying the error does not allow access to the system, regardless of whether it is accessed with the name of an existing database in the subdomain unless the rails server is restarted.

This is my code in my ApplicationController:

class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception
  before_action :connect_to_database


  def connect_to_user_database(name)
    config = ActiveRecord::Base.configurations["development"].merge("database" => "#{name}")
    ActiveRecord::Base.establish_connection(config)
    #auth = name
    #raise auth.to_yaml #podemos ver los datos que nos ofrece el parametro
  end


  private

  def connect_to_database
    connect_to_user_database(request.subdomains(0).first)
  end

end

For security and to avoid errors, you should check if subdomain is valid before `connect_to_database`. — wesley6j, May 31 '17 at 21:52
@wesley6j thanks for answer, but how can I check if the database exist? — Ing.LuisC, May 31 '17 at 21:56
If you have a list of subdomains that you want to use, save the array somewhere in your codebase or config file. — wesley6j, May 31 '17 at 22:01
Are you able to `rescue StandardError render file: "#{Rails.root}/public/404", layout: true, status: :not_found end` — Md. Farhan Memon, Jun 01 '17 at 04:55

Michael Gorman · Answer 1 · 2017-06-01T13:25:42.073

0

Using something like what is done in this answer https://stackoverflow.com/a/25592558/8088139 build a catch situation to fail gracefully if the database doesn't exist

something like

def connect_to_user_database(name)
  config = ActiveRecord::Base.configurations["development"].merge("database" => "#{name}")
  ActiveRecord::Base.establish_connection(config)
rescue ActiveRecord::NoDatabaseError
  clear_cache!
  #set response to forbidden
  #log the failure
end

EDIT: added clear_cache! to NoDatabaseError rescue

edited Jun 01 '17 at 13:25

answered May 31 '17 at 21:50

Michael Gorman

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Thanks for replying, I pasted the code but it still shows me the same error – Ing.LuisC May 31 '17 at 22:27
Try running this command in the rescue case "clear_cache!" editing answer with this – Michael Gorman Jun 01 '17 at 13:24
I placed your code and I started the rails server but I still get the same error when I enter the name of an existing database when I first enter a database that does not exist. – Ing.LuisC Jun 01 '17 at 18:40
Then I would suggest what wesley6j suggested, creating a white list of acceptable subdomains, and not even attempting a db connection if the incoming domain isn't in the whitelist – Michael Gorman Jun 01 '17 at 18:46
Thanks, I'll go for that option. – Ing.LuisC Jun 07 '17 at 16:54

Error trying to change database

1 Answers1