Instance variables in helpers?

rubyonrails-talk
1

Hi,

Can someone tell me why the following isn’t setting an instance variable? Perhaps they can’t be set/used in helpers? I have a revision_info method in ApplicationHelper that returns the current SVN revision number (used for debugging info in the footer):

module ApplicationHelper def revision_info logger.info(“In revision_info(); rev=#{@rev}”) # @rev is always nil if (@rev ||= (capistrano_revision_info || svn_revision_info)).blank?

  return nil
else
  return 'Revision ' + @rev
end

end end

capistrano_revision_info returns the revision number from the REVISION file

capistrano_revision_info returns the revision number from svn info --xml

Thanks in advance for any replies.

Cheers, Lee

2

At least I can tell you that it *is* possible to set instance variables in helper methods *and* get them when calling the same helper later on, so the problem must be somewhere else in the code. Did you try going to the console and check what the two methods #capistrano_revision_info and #svn_revision_info actually returns? Maybe that's the problem, I don't know, but it's definitely not the instance variables.

3

But you can only use the member variables from the class(es) which include the module.

James.

4

maybe i misunderstand, but what i see is a helper-method in application_helper. i don't know how many times you call that method in one single view, but if you call it only once @rev is not yet set when you write it into your log file.

does the method return your revision-number correctly?

if so, why don't you just write something like this:

  Footer ... <%= revision_info %>