canvas-lms/lib/browser_support.rb

74 lines
2.5 KiB
Ruby

# frozen_string_literal: true
#
# Copyright (C) 2013 - present Instructure, Inc.
#
# This file is part of Canvas.
#
# Canvas is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, version 3 of the License.
#
# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
require "browser/browser"
BrowserSupport = Struct.new(:browser, :version) do
class << self
def supported?(user_agent)
browser = Browser.new(user_agent)
return true if respondus? browser
return true if chrome_os_lts? browser
return false if minimum_browsers.any? { |min| browser.send("#{min.browser}?", "<#{min.version}") }
true # if we don't recognize it (e.g. Android), be nice
end
def configuration
@configuration ||= YAML.load_file(File.expand_path("../config/browsers.yml", __dir__))
end
def minimum_browsers
@minimum_browsers ||= (configuration["minimums"] || [])
.map { |browser, version| new(browser, version.to_s) }
end
private
def lts
@lts = OpenStruct.new(configuration["chrome_os_lts"])
end
#
# Respondus lockdown browser includes a telltale in the User-Agent string which
# is platform-dependent. Hopefully this never needs to be modified.
#
def respondus?(browser)
return true if browser.platform.mac? && browser.ua.match(/ CMAC \d[.\d]+;/)
return true if browser.platform.windows? && browser.ua.match(/ CLDB \d[.\d]+;/)
false
end
#
# Chrome OS has a long-term support (LTS) channel which is updated every 6 months.
# Unfortunately, the LTS distinction is not reflected in the User-Agent string.
# This method checks if the browser is Chrome running on Chrome OS and compares it
# to the specific major LTS version specified in the configuration file.
#
def chrome_os_lts?(browser)
return false unless browser.platform.chrome_os?
return false unless browser.chrome?(lts.chrome)
return true if /X11; CrOS \w+ #{lts.platform}/.match?(browser.ua)
false
end
end
end