Best practise for setting default URL parameters in the controller - Rails

Question

I've been trying to set default URL parameters in the controller, which will also be used within the view. This is what I've got:

@params = params

defaults = { :date_from => '21/1/21014', :date_to => '21/2/21014', :data=>"Expense" }
if @params.any?
 @params = defaults.merge(@params)
else
 @params = defaults
end

.. seems messy, and doesn't work :( When params are present it still uses the default params. Not sure where it's going wrong and search on google yields many varieties. I know using default values in methods is something that I will repeat again so I was wondering what the best practice is for handling this.

Answer 1

That is likely because it should be params not @params. I don't think you need the .any? test either, just let it merge the empty hash into defaults.

If you need to do this in more than one controller method then use a before filter.

Answer 2

Personally, I'd say "best practice" is "don't do that" :-)

Instead of passing raw params to a view, build your model object (or a service object) with them and pass that in. And if you need defaults for missing attributes specified, the model/s.o. would be a better place for them.