How to test if parameters exist in rails

Solution 1:

You want has_key?:

if(params.has_key?(:one) && params.has_key?(:two))

Just checking if(params[:one]) will get fooled by a "there but nil" and "there but false" value and you're asking about existence. You might need to differentiate:

• Not there at all.
• There but nil.
• There but false.
• There but an empty string.

as well. Hard to say without more details of your precise situation.

Solution 2:

I am a fan of

params[:one].present?

Just because it keeps the params[sym] form so it's easier to read.

Solution 3:

use blank? http://api.rubyonrails.org/classes/Object.html#method-i-blank-3F

unless params[:one].blank? && params[:two].blank?

will return true if its empty or nil

also... that will not work if you are testing boolean values.. since

>> false.blank?
=> true

in that case you could use

unless params[:one].to_s.blank? && params[:two].to_s.blank?

Solution 4:

You can write it more succinctly like the following:

required = [:one, :two, :three]
if required.all? {|k| params.has_key? k}
  # here you know params has all the keys defined in required array
else
  ...
end