instance method `rescue_from`

Ruby on Rails 6.0.6

Since v2.2.3

Available in: v2.2.3 v2.3.18 v3.0.20 v3.1.12 v3.2.22.5 v4.0.13 v4.1.16 v4.2.9 v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

rescue_from(*klasses, with: nil, &block)

Rescue exceptions raised in controller actions.

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

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

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

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

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

  private
    def deny_access
      ...
    end

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

Exceptions raised inside exception handlers are not propagated up.

Parameters

klasses rest
with key = nil
block block

Source

# File activesupport/lib/active_support/rescuable.rb, line 51
      def rescue_from(*klasses, with: nil, &block)
        unless with
          if block_given?
            with = block
          else
            raise ArgumentError, "Need a handler. Pass the with: keyword argument or provide a block."
          end
        end

        klasses.each do |klass|
          key = if klass.is_a?(Module) && klass.respond_to?(:===)
            klass.name
          elsif klass.is_a?(String)
            klass
          else
            raise ArgumentError, "#{klass.inspect} must be an Exception class or a String referencing an Exception class"
          end

          # Put the new handler at the end because the list is read in reverse.
          self.rescue_handlers += [[key, with]]
        end
      end

Defined in activesupport/lib/active_support/rescuable.rb line 51 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveSupport::Rescuable::ClassMethods

Signature

Parameters