Exception: ActionController::ParameterMissing
| Relationships & Source Files | |
| Super Chains via Extension / Inclusion / Inheritance | |
| Class Chain: 
          self,
          KeyError
         | |
| Instance Chain: 
          self,
          KeyError
         | |
| Inherits: | KeyError 
 | 
| Defined in: | actionpack/lib/action_controller/metal/strong_parameters.rb | 
Overview
Raised when a required parameter is missing.
params = ActionController::Parameters.new(a: {})
params.fetch(:b)
# => ActionController::ParameterMissing: param not found: b
params.require(:a)
# => ActionController::ParameterMissing: param not found: a