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v7.1.0
class ActionController::ParameterMissing < KeyError

ActionController::ParameterMissing

Raised when a required parameter is missing.

params = ActionController::Parameters.new(a: {})
params.fetch(:b)
# => ActionController::ParameterMissing: param is missing or the value is empty: b
params.require(:a)
# => ActionController::ParameterMissing: param is missing or the value is empty: a
Definition files