class ActionDispatch::PermissionsPolicy

keep the old header name and implementation for now.
middleware in the future we use the new name for the middleware but
yet supported by all browsers. To avoid having to rename this
The Permissions-Policy requires a different implementation and isn’t
The Feature-Policy header has been renamed to Permissions-Policy.
end
policy.payment :self, “secure.example.com”
policy.fullscreen :self
policy.usb :none
policy.microphone :none
policy.gyroscope :none
policy.camera :none
Rails.application.config.permissions_policy do |policy|
Example global policy:
its iframes can use.
response header to specify which browser features the current document and
Configures the HTTP
= Action Dispatch PermissionsPolicy
:nodoc:

def apply_mapping(source) 

def apply_mapping(source)
  MAPPINGS.fetch(source) do
    raise ArgumentError, "Unknown HTTP permissions policy source mapping: #{source.inspect}"
  end
end

def apply_mappings(sources) 

def apply_mappings(sources)
  sources.map do |source|
    case source
    when Symbol
      apply_mapping(source)
    when String, Proc
      source
    else
      raise ArgumentError, "Invalid HTTP permissions policy source: #{source.inspect}"
    end
  end
end

def build(context = nil) 

def build(context = nil)
  build_directives(context).compact.join("; ")
end

def build_directive(sources, context) 

def build_directive(sources, context)
  sources.map { |source| resolve_source(source, context) }
end

def build_directives(context) 

def build_directives(context)
  @directives.map do |directive, sources|
    if sources.is_a?(Array)
      "#{directive} #{build_directive(sources, context).join(' ')}"
    elsif sources
      directive
    else
      nil
    end
  end
end

def initialize 

def initialize
  @directives = {}
  yield self if block_given?
end

def initialize_copy(other) 

def initialize_copy(other)
  @directives = other.directives.deep_dup
end

def resolve_source(source, context) 

def resolve_source(source, context)
  case source
  when String
    source
  when Symbol
    source.to_s
  when Proc
    if context.nil?
      raise RuntimeError, "Missing context for the dynamic permissions policy source: #{source.inspect}"
    else
      context.instance_exec(&source)
    end
  else
    raise RuntimeError, "Unexpected permissions policy source: #{source.inspect}"
  end
end