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| pp.camera :none pp.fullscreen :self pp.clipboard_read :self, 'https://example.com' end
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| pp.camera :self end # ... end
In addition to using a block, you can also call methods on the object returned by the method:
r.get 'foo' do permissions_policy.camera :self # ... end
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:
:all |
Grants permission to all domains (must be only argument) |
:none |
Does not allow permission at all (must be only argument) |
:self |
Allows feature in current document and any nested browsing contexts that use the same domain as the current document. |
:src |
Allows feature in current document and any nested browsing contexts that use the same domain as the src of the iframe. |
String |
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, 'https://example.com' # fullscreen (self "https://example.com") permissions_policy.add_fullscreen 'https://*.example.com' # fullscreen (self "https://example.com" "https://*.example.com") permissions_policy.get_fullscreen # => [:self, "https://example.com", "https://*.example.com"]
The clear method can be used to remove all settings from the policy.
Classes and Modules
Public Class methods
Yield the current Permissions Policy
to the block.
# 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 279 Policy.new 280 end 281 282 if default = opts[:default] 283 SUPPORTED_SETTINGS.each do |setting| 284 policy.send(setting.gsub('-', '_'), *default) 285 end 286 end 287 288 yield policy if defined?(yield) 289 policy.freeze 290 end