module ActiveSupport::Rescuable::ClassMethods

Exceptions raised inside exception handlers are not propagated up.

end
end
exception.record.new_record? ? ...
def show_errors(exception)

end
...
def deny_access
protected

end
render xml: exception, status: 500
rescue_from 'MyAppError::Base' do |exception|

rescue_from ActiveRecord::RecordInvalid, with: :show_errors
rescue_from User::NotAuthorized, with: :deny_access # self defined exception
class ApplicationController < ActionController::Base

any.
which exception.is_a?(klass) holds true is the one invoked, if
bottom to top, and up the hierarchy. The handler of the first class for
Handlers are inherited. They are searched from right to left, from

that the exception can be inspected when dealing with it.
Handlers that take one argument will be called with the exception, so

be given.
or a Proc object to be called to handle them. Alternatively a block can
names, and a trailing :with option with the name of a method
rescue_from receives a series of exception classes or class

Rescue exceptions raised in controller actions.

def rescue_from(*klasses, &block)
  options = klasses.extract_options!
  unless options.has_key?(:with)
    if block_given?
      options[:with] = block
    else
      raise ArgumentError, "Need a handler. Supply an options hash that has a :with key as the last argument."
    end
  end
  klasses.each do |klass|
    key = if klass.is_a?(Class) && klass <= Exception
      klass.name
    elsif klass.is_a?(String)
      klass
    else
      raise ArgumentError, "#{klass} is neither an Exception nor a String"
    end
    # put the new handler at the end because the list is read in reverse
    self.rescue_handlers += [[key, options[:with]]]
  end
end