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|
# frozen_string_literal: true
# :markup: markdown
module ActionController # :nodoc:
module AllowBrowser
extend ActiveSupport::Concern
module ClassMethods
# Specify the browser versions that will be allowed to access all actions (or
# some, as limited by `only:` or `except:`). Only browsers matched in the hash
# or named set passed to `versions:` will be blocked if they're below the
# versions specified. This means that all other browsers, as well as agents that
# aren't reporting a user-agent header, will be allowed access.
#
# A browser that's blocked will by default be served the file in
# public/406-unsupported-browser.html with a HTTP status code of "406 Not
# Acceptable".
#
# In addition to specifically named browser versions, you can also pass
# `:modern` as the set to restrict support to browsers natively supporting webp
# images, web push, badges, import maps, CSS nesting, and CSS :has. This
# includes Safari 17.2+, Chrome 120+, Firefox 121+, Opera 106+.
#
# You can use https://caniuse.com to check for browser versions supporting the
# features you use.
#
# You can use `ActiveSupport::Notifications` to subscribe to events of browsers
# being blocked using the `browser_block.action_controller` event name.
#
# Examples:
#
# class ApplicationController < ActionController::Base
# # Allow only browsers natively supporting webp images, web push, badges, import maps, CSS nesting, and CSS :has
# allow_browser versions: :modern
# end
#
# class ApplicationController < ActionController::Base
# # All versions of Chrome and Opera will be allowed, but no versions of "internet explorer" (ie). Safari needs to be 16.4+ and Firefox 121+.
# allow_browser versions: { safari: 16.4, firefox: 121, ie: false }
# end
#
# class MessagesController < ApplicationController
# # In addition to the browsers blocked by ApplicationController, also block Opera below 104 and Chrome below 119 for the show action.
# allow_browser versions: { opera: 104, chrome: 119 }, only: :show
# end
def allow_browser(versions:, block: -> { render file: Rails.root.join("public/406-unsupported-browser.html"), layout: false, status: :not_acceptable }, **options)
before_action -> { allow_browser(versions: versions, block: block) }, **options
end
end
private
def allow_browser(versions:, block:)
require "useragent"
if BrowserBlocker.new(request, versions: versions).blocked?
ActiveSupport::Notifications.instrument("browser_block.action_controller", request: request, versions: versions) do
instance_exec(&block)
end
end
end
class BrowserBlocker # :nodoc:
SETS = {
modern: { safari: 17.2, chrome: 120, firefox: 121, opera: 106, ie: false }
}
attr_reader :request, :versions
def initialize(request, versions:)
@request, @versions = request, versions
end
def blocked?
user_agent_version_reported? && unsupported_browser?
end
private
def parsed_user_agent
@parsed_user_agent ||= UserAgent.parse(request.user_agent)
end
def user_agent_version_reported?
request.user_agent.present? && parsed_user_agent.version.to_s.present?
end
def unsupported_browser?
version_guarded_browser? && version_below_minimum_required? && !bot?
end
def version_guarded_browser?
minimum_browser_version_for_browser != nil
end
def bot?
parsed_user_agent.bot?
end
def version_below_minimum_required?
if minimum_browser_version_for_browser
parsed_user_agent.version < UserAgent::Version.new(minimum_browser_version_for_browser.to_s)
else
true
end
end
def minimum_browser_version_for_browser
expanded_versions[normalized_browser_name]
end
def expanded_versions
@expanded_versions ||= (SETS[versions] || versions).with_indifferent_access
end
def normalized_browser_name
case name = parsed_user_agent.browser.downcase
when "internet explorer" then "ie"
else name
end
end
end
end
end
|
