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# frozen_string_literal: true
require 'digest/md5'
module WebSocket
module Handshake
module Handler
class Client76 < Client75
# @see WebSocket::Handshake::Base#valid?
def valid?
super && verify_challenge && verify_protocol
end
private
# @see WebSocket::Handshake::Base#reserved_leftover_lines
def reserved_leftover_lines
1
end
# @see WebSocket::Handshake::Handler::Base#handshake_keys
def handshake_keys
keys = super
keys << ['Sec-WebSocket-Key1', key1]
keys << ['Sec-WebSocket-Key2', key2]
keys
end
# @see WebSocket::Handshake::Handler::Base#finishing_line
def finishing_line
key3
end
# Sec-WebSocket-Key1 value
# @return [String] key
def key1
@key1 ||= generate_key(:key1)
end
# Sec-WebSocket-Key2 value
# @return [String] key
def key2
@key2 ||= generate_key(:key2)
end
# Value of third key, sent in body
# @return [String] key
def key3
@key3 ||= generate_key3
end
# Expected challenge that should be sent by server
# @return [String] challenge
def challenge
return @challenge if defined?(@challenge)
key1 && key2
sum = [@key1_number].pack('N*') +
[@key2_number].pack('N*') +
key3
@challenge = Digest::MD5.digest(sum).strip
end
# Verify if challenge sent by server match generated one
# @return [Boolena] True if challenge matches, false otherwise(sets appropriate error)
def verify_challenge
raise WebSocket::Error::Handshake::InvalidAuthentication unless @handshake.leftovers == challenge
true
end
NOISE_CHARS = ("\x21".."\x2f").to_a + ("\x3a".."\x7e").to_a
# Generate Sec-WebSocket-Key1 and Sec-WebSocket-Key2
# @param key [String] name of key. Will be used to set number variable needed later. Valid values: key1, key2
# @return [String] generated key
def generate_key(key)
spaces = rand(1..12)
max = 0xffffffff / spaces
number = rand(max + 1)
instance_variable_set("@#{key}_number", number)
key = (number * spaces).to_s
rand(1..12).times do
char = NOISE_CHARS[rand(NOISE_CHARS.size)]
pos = rand(key.size + 1)
key[pos...pos] = char
end
spaces.times do
pos = 1 + rand(key.size - 1)
key[pos...pos] = ' '
end
key
end
# Generate third key
def generate_key3
[rand(0x100000000)].pack('N') + [rand(0x100000000)].pack('N')
end
def provided_protocols
Array(@handshake.headers['sec-websocket-protocol'].to_s.strip)
end
end
end
end
end
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