Shorthand for accessing values from params hash

Question

I often feel the need to access the individual key-value pairs from the 'params' hash, as if they were local variables.

I find that using local variables instead of writing 'params' every time, makes my code easier to understand.

So instead of using the values like params[:first_variable] I would do something like :

first_var  = params[:first_variable]

second_var = params[:second_variable]
... 

and in my program i would use this short notation instead of writing params[:first_var] every time.

The problem with this is that the size of my functions can grow significantly, when I have many values in params.

Is there a better way to reference the objects from 'params' as local variables in my function ?

Answer 1

You could redefine method_missing in which class you want this functionality. If you do, remember the cardinal rules of method_missing - if you can't handle it, call pass it on (to super); and update respond_to? in parallel.

Something like this, perhaps.

class Foo
  def method_missing(name, *args, &block)
    if params.include? name
      params[:name]
    else
      super
    end
  end

  def respond_to?(name)
    if params.include? name
      true
    else
      super
    end
  end
end

Remember that Rails makes heavy use of method_missing already, so either only redefine it on your own classes, or alias the existing version and call that instead of super when you aren't handling.