lib/websocket/handshake/handler/client04.rb
# frozen_string_literal: true
require 'digest/sha1'
require 'base64'
module WebSocket
module Handshake
module Handler
class Client04 < Client
# @see WebSocket::Handshake::Base#valid?
def valid?
super && verify_accept && verify_protocol
end
private
# @see WebSocket::Handshake::Handler::Base#handshake_keys
def handshake_keys
keys = [
%w[Upgrade websocket],
%w[Connection Upgrade]
]
host = @handshake.host
host += ":#{@handshake.port}" unless @handshake.default_port?
keys << ['Host', host]
keys += super
keys << ['Sec-WebSocket-Origin', @handshake.origin] if @handshake.origin
keys << ['Sec-WebSocket-Version', @handshake.version]
keys << ['Sec-WebSocket-Key', key]
keys << ['Sec-WebSocket-Protocol', @handshake.protocols.join(', ')] if @handshake.protocols.any?
keys
end
# Sec-WebSocket-Key value
# @return [String] key
def key
@key ||= [(1..16).map { rand(255).chr } * ''].pack('m').strip
end
# Value of Sec-WebSocket-Accept that should be delivered back by server
# @return [Sering] accept
def accept
@accept ||= [Digest::SHA1.digest(key + '258EAFA5-E914-47DA-95CA-C5AB0DC85B11')].pack('m').strip
end
# Verify if received header Sec-WebSocket-Accept matches generated one.
# @return [Boolean] True if accept is matching. False otherwise(appropriate error is set)
def verify_accept
raise WebSocket::Error::Handshake::InvalidAuthentication unless @handshake.headers['sec-websocket-accept'] == accept
true
end
def supported_protocols
@handshake.protocols
end
def provided_protocols
@handshake.headers['sec-websocket-protocol'].to_s.split(/ *, */)
end
end
end
end
end