Access to an ApplicationController property from a view


#1

Hi there,

How is it possible to get access to an ApplicationController property
from a view?

Consider this (simplified) situation:

class ApplicationController < ActionController::Base
def folder_id
@folder_id = params[:id]
return @folder_id
end
end

class FolderController < ApplicationController
def show
@folder = Folder.find_by_id(folder_id)
end
end

So far, so good, BUT… when trying to access folder_id in the show-view
like this <%= folder_id %>, I get an error (undefined local variable or
method `folder_id’). Is this possible or do I NEED to use instance
variables – which I’d rather not do?

Thanks.

Mischa.


Open source file management webapp :: Boxroom ::
http://boxroom.rubyforge.org/


#2

Hi Mischa,

Mischa B. wrote:

So far, so good, BUT… when trying to access folder_id in the show-view
like this <%= folder_id %>, I get an error (undefined local variable or
method `folder_id’). Is this possible or do I NEED to use instance
variables – which I’d rather not do?

You’ll need to use instance variables. By definition, the scope of a
local
variable is the block within which it’s declared. A local variable
declared
in a controller action method only has meaning within that action
method.
Not only is it not available in a view, it’s not available in any of the
other action methods in the controller.

Just as a point of information, what’s your issue with using instance
variables?

Best regards,
Bill


#3

You’ll need to use instance variables. By definition, the scope of a
local variable is the block within which it’s declared. A local
variable declared in a controller action method only has meaning within
that action method. Not only is it not available in a view, it’s not
available in any of the other action methods in the controller.

Yeah, but I’m not trying to use a local variable, I’m trying to access
the method folder_id which returns @folder_id.

Why IS it possible to use params[:id] instead of @params[:id] in a view
and why ISN’T it possible to use folder_id instead of @folder_id like
I’m trying to do in my example?

Just as a point of information, what’s your issue with using instance
variables?

I’m trying to encapsulate @folder_id. The view only has to know about
folder_id. In the method I can set @folder_id to different values
according to the situation and return the appropriate value.

Best regards,
Bill

Thanks again.


#4

On Thu, May 18, 2006 at 10:11:29PM +0200, Mischa B. wrote:
} Hi there,
}
} How is it possible to get access to an ApplicationController property
} from a view?
}
} Consider this (simplified) situation:
}
} class ApplicationController < ActionController::Base
} def folder_id
} @folder_id = params[:id]
} return @folder_id
} end
} end
}
} class FolderController < ApplicationController
} def show
} @folder = Folder.find_by_id(folder_id)
} end
} end
}
} So far, so good, BUT… when trying to access folder_id in the
show-view
} like this <%= folder_id %>, I get an error (undefined local variable
or
} method `folder_id’). Is this possible or do I NEED to use instance
} variables – which I’d rather not do?

<%= controller.folder_id %>

} Thanks.
} Mischa.
–Greg