How can I declare a global variable in Ruby on Rails?
My sample code:
in my controller#application.rb:
def user_clicked()
@current_userid = params[:user_id]
end
in my layout#application.html.haml I have sidebar with this link:
= link_to "John", user_clicked_path(:user_id => 1)
= link_to "Doe", user_clicked_path(:user_id => 2)
= link_to "View clicked user", view_user_path
in my views#view_user.html.haml:
%h2 @current_userid
I want to declare a global variable that can modify my controller and use it anywhere, like controller, views, and etc. The above is only a sample scenario. If I click the John or Doe link, it will send a user_id to the controller and when I click the "View clicked user" link, it will display the last clicked link. It is either John=1 or Doe=2.
Of course if I click the "View clicked user" link first, it will display nil.
In Ruby global variables are declared by prefixing the identifier with $
$foo = 'bar'
Which you rarely see used for a number of reasons. And it's not really what you are looking for.
In Ruby instance variables are declared with @:
class DemoController
def index
@some_variable = "dlroW olleH"
@some_variable = backwards
end
private
def backwards
@some_variable.reverse
end
end
Rails automatically passes the controller's instance variables to the view context.
# /app/views/demos/index.html.haml
%h1= @some_variable
Guess what it outputs and I'll give you a cookie.
In your example @global_variable is nil since controller#sample_1 is not called - the request would go through controller#sample_2.
def sample_2
@global_variable = "Hello World"
end
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