lib/websocket/handshake/handler/server04.rb
# frozen_string_literal: true
require 'digest/sha1'
require 'base64'
module WebSocket
module Handshake
module Handler
class Server04 < Server
# @see WebSocket::Handshake::Base#valid?
def valid?
super && verify_key
end
private
# @see WebSocket::Handshake::Handler::Base#header_line
def header_line
'HTTP/1.1 101 Switching Protocols'
end
# @see WebSocket::Handshake::Handler::Base#handshake_keys
def handshake_keys
[
%w[Upgrade websocket],
%w[Connection Upgrade],
['Sec-WebSocket-Accept', signature]
] + protocol
end
# Signature of response, created from client request Sec-WebSocket-Key
# @return [String] signature
def signature
return unless key
string_to_sign = "#{key}258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
[Digest::SHA1.digest(string_to_sign)].pack('m').chomp
end
def verify_key
raise WebSocket::Error::Handshake::InvalidAuthentication unless key
true
end
def key
@handshake.headers['sec-websocket-key']
end
def protocol
return [] unless @handshake.headers.key?('sec-websocket-protocol')
protos = @handshake.headers['sec-websocket-protocol'].split(/ *, */) & @handshake.protocols
[['Sec-WebSocket-Protocol', protos.first]]
end
end
end
end
end