module Kemal::Shield

Overview

Kemal::Shield is a module that contains a collection of Kemal handlers. These handlers sets/unsets different HTTP response headers adding an extra layer of protection.

Kemal::Shield.activate # => Adds all the handlers

It is also possible to add just the handlers that you are interested in.

add_handler Kemal::Shield::XPoweredBy.new # => Removes the X-Powered-By header
add_handler Kemal::Shield::XXSSProtection.new # => Sets X-XSS-Protection to "0"

The different headers can be configured in the same way as Kemal:

Kemal::Shield.config do |config|
  config.csp_on = true
  config.hide_powered_by = true
  config.no_sniff = true
  config.referrer_policy = ["no-referrer"]
  config.x_xss_protection = false
end

Defined in:

Constant Summary

HANDLERS = [] of Shield::Handler.class

VERSION = "0.4.0"

Class Method Summary

• .activate

  Adds a collection of Kemal::Shield::Handler.

• .add_handler(handler : Shield::Handler)

  Adds a Kemal::Shield::Handler.

• .config(&)
• .config
• .deactivate

  Removes all Kemal::Shield::Handler.

• .remove_handler(handler : Shield::Handler.class)

  Removes a Kemal::Shield::Handler.

Class Method Detail

Kemal::Shield.activate

class CustomHandler < Kemal::Shield::Handler
  def call(context)
    # code ...
    call_next context
  end
end

Kemal::Shield.add_handler CustomHandler.new

Kemal::Shield.add_handler CustomHandler.new # => okay
Kemal::Shield.add_handler CustomHandler.new # => raises DublicateHandlerError

Kemal::Shield.deactivate

Kemal::Shield.activate

Kemal::Shield.remove_handler Kemal::Shield::ExpectCT # => Kemal::Shield::ExpectCT object
Kemal::Shield.remove_handler Kemal::Shield::ExpectCT # => nil