module Roda::RodaPlugins::PermissionsPolicy

  1. lib/roda/plugins/permissions_policy.rb

A permissions_policy plugin has been added that allows you to easily set a Permissions-Policy header for the application, which browsers can use to determine whether to allow specific functionality on the returned page (mainly related to which JavaScript APIs the page is allowed to use).

You would generally call the plugin with a block to set the default policy:

plugin :permissions_policy do |pp| :none
  pp.fullscreen :self
  pp.clipboard_read :self, ''

Then, anywhere in the routing tree, you can customize the policy for just that branch or action using the same block syntax:

r.get 'foo' do
  permissions_policy do |pp| :self
  # ...

In addition to using a block, you can also call methods on the object returned by the method:

r.get 'foo' do :self
  # ...

You can use the :default plugin option to set the default for all settings. For example, to disallow all access for each setting by default:

plugin :permissions_policy, default: :none

The following methods are available for configuring the permissions policy, which specify the setting (substituting _ with -):

  • accelerometer

  • ambient_light_sensor

  • autoplay

  • bluetooth

  • camera

  • clipboard_read

  • clipboard_write

  • display_capture

  • encrypted_media

  • fullscreen

  • geolocation

  • gyroscope

  • hid

  • idle_detection

  • keyboard_map

  • magnetometer

  • microphone

  • midi

  • payment

  • picture_in_picture

  • publickey_credentials_get

  • screen_wake_lock

  • serial

  • sync_xhr

  • usb

  • web_share

  • window_management

All of these methods support any number of arguments, and each argument should be one of the following values:


Grants permission to all domains (must be only argument)


Does not allow permission at all (must be only argument)


Allows feature in current document and any nested browsing contexts that use the same domain as the current document.


Allows feature in current document and any nested browsing contexts that use the same domain as the src of the iframe.


Specifies origin domain where access is allowed

When calling a method with no arguments, the setting is removed from the policy instead of being left empty, since all of these setting require at least one value. Likewise, if the policy does not have any settings, the header will not be added.

Calling the method overrides any previous setting. Each of the methods has add_* and get_* methods defined. The add_* method appends to any existing setting, and the get_* method returns the current value for the setting (this will be :all if all domains are allowed, or any array of strings/:self/:src).

permissions_policy.fullscreen :self, ''
# fullscreen (self "")

permissions_policy.add_fullscreen 'https://*'
# fullscreen (self "" "https://*")

# => [:self, "", "https://*"]

The clear method can be used to remove all settings from the policy.


Public Class

  1. configure

Public Class methods

configure(app, opts=OPTS)

Yield the current Permissions Policy to the block.

[show source]
    # File lib/roda/plugins/permissions_policy.rb
275 def self.configure(app, opts=OPTS)
276   policy = app.opts[:permissions_policy] = if policy = app.opts[:permissions_policy]
277     policy.dup
278   else
280   end
282   if default = opts[:default]
283     SUPPORTED_SETTINGS.each do |setting|
284       policy.send(setting.gsub('-', '_'), *default)
285     end
286   end
288   yield policy if defined?(yield)
289   policy.freeze
290 end