Is Rails shared-nothing or can separate requests access the same runtime variables?

Question

PHP runs in a shared-nothing environment, which in this context means that every web request is run in a clean environment. You can not access another request\'s data excep

Answer 1

Here is a relatively simple example that illustrates what can happen if you are not careful about modifying shared objects.

1. Create a new Rails project: rails test

2. Create a new file lib/misc.rb and put in it this:

   class Misc
     @xxx = 'Hello'
     def Misc.contents()
       return @xxx
     end
   end
   

3. Create a new controller: ruby script/generate controller Posts index

4. Change app/views/posts/index.html.erb to contain this code:

   <%
     require 'misc'; y = Misc.contents() ; y << ' (goodbye) '
   %>
   <%= y %>
   

   (This is where we modify the implicitly shared object.)

5. Add RESTful routes to config/routes.rb.
6. Start the server ruby script/server and load the page /posts several times. You will see the number of ( goodbye) strings increasing by one on each successive page reload.