Helpers: Add inv_sig_helper client

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Samantaz Fox 2024-07-01 22:24:24 +02:00
parent a845752fff
commit 56a7488161
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@ -0,0 +1,303 @@
require "uri"
require "socket"
require "socket/tcp_socket"
require "socket/unix_socket"
private alias NetworkEndian = IO::ByteFormat::NetworkEndian
class Invidious::SigHelper
enum UpdateStatus
Updated
UpdateNotRequired
Error
end
# -------------------
# Payload types
# -------------------
abstract struct Payload
end
struct StringPayload < Payload
getter value : String
def initialize(str : String)
raise Exception.new("SigHelper: String can't be empty") if str.empty?
@value = str
end
def self.from_io(io : IO)
size = io.read_bytes(UInt16, NetworkEndian)
if size == 0 # Error code
raise Exception.new("SigHelper: Server encountered an error")
end
if str = io.gets(limit: size)
return self.new(str)
else
raise Exception.new("SigHelper: Can't read string from socket")
end
end
def self.to_io(io : IO)
# `.to_u16` raises if there is an overflow during the conversion
io.write_bytes(@value.bytesize.to_u16, NetworkEndian)
io.write(@value.to_slice)
end
end
private enum Opcode
FORCE_UPDATE = 0
DECRYPT_N_SIGNATURE = 1
DECRYPT_SIGNATURE = 2
GET_SIGNATURE_TIMESTAMP = 3
GET_PLAYER_STATUS = 4
end
private struct Request
def initialize(@opcode : Opcode, @payload : Payload?)
end
end
# ----------------------
# High-level functions
# ----------------------
module Client
# Forces the server to re-fetch the YouTube player, and extract the necessary
# components from it (nsig function code, sig function code, signature timestamp).
def force_update : UpdateStatus
request = Request.new(Opcode::FORCE_UPDATE, nil)
value = send_request(request) do |io|
io.read_bytes(UInt16, NetworkEndian)
end
case value
when 0x0000 then return UpdateStatus::Error
when 0xFFFF then return UpdateStatus::UpdateNotRequired
when 0xF44F then return UpdateStatus::Updated
else
raise Exception.new("SigHelper: Invalid status code received")
end
end
# Decrypt a provided n signature using the server's current nsig function
# code, and return the result (or an error).
def decrypt_n_param(n : String) : String
request = Request.new(Opcode::DECRYPT_N_SIGNATURE, StringPayload.new(n))
n_dec = send_request(request) do |io|
StringPayload.from_io(io).string
rescue ex
LOGGER.debug(ex.message)
nil
end
return n_dec
end
# Decrypt a provided s signature using the server's current sig function
# code, and return the result (or an error).
def decrypt_sig(sig : String) : String?
request = Request.new(Opcode::DECRYPT_SIGNATURE, StringPayload.new(sig))
sig_dec = send_request(request) do |io|
StringPayload.from_io(io).string
rescue ex
LOGGER.debug(ex.message)
nil
end
return sig_dec
end
# Return the signature timestamp from the server's current player
def get_sts : UInt64?
request = Request.new(Opcode::GET_SIGNATURE_TIMESTAMP, nil)
return send_request(request) do |io|
io.read_bytes(UInt64, NetworkEndian)
end
end
# Return the signature timestamp from the server's current player
def get_player : UInt32?
request = Request.new(Opcode::GET_PLAYER_STATUS, nil)
send_request(request) do |io|
has_player = io.read_bytes(UInt8) == 0xFF
player_version = io.read_bytes(UInt32, NetworkEndian)
end
return has_player ? player_version : nil
end
private def send_request(request : Request, &block : IO)
channel = Multiplexor.send(request)
data_io = channel.receive
return yield data_io
rescue ex
LOGGER.debug(ex.message)
return nil
end
end
# ---------------------
# Low level functions
# ---------------------
class Multiplexor
alias TransactionID = UInt32
record Transaction, channel = ::Channel(Bytes).new
@prng = Random.new
@mutex = Mutex.new
@queue = {} of TransactionID => Transaction
@conn : Connection
INSTANCE = new
def initialize
@conn = Connection.new
listen
end
def initialize(url : String)
@conn = Connection.new(url)
listen
end
def listen : Nil
raise "Socket is closed" if @conn.closed?
# TODO: reopen socket if unexpectedly closed
spawn do
loop do
receive_data
Fiber.sleep
end
end
end
def self.send(request : Request)
transaction = Transaction.new
transaction_id = @prng.rand(TransactionID)
# Add transaction to queue
@mutex.synchronize do
# On a 64-bits random integer, this should never happen. Though, just in case, ...
if @queue[transaction_id]?
raise Exception.new("SigHelper: Duplicate transaction ID! You got a shiny pokemon!")
end
@queue[transaction_id] = transaction
end
write_packet(transaction_id, request)
return transaction.channel
end
def receive_data : Payload
# Read a single packet from socker
transaction_id, data_io = read_packet
# Remove transaction from queue
@mutex.synchronize do
transaction = @queue.delete(transaction_id)
end
# Send data to the channel
transaction.channel.send(data)
end
# Read a single packet from the socket
private def read_packet : {TransactionID, IO}
# Header
transaction_id = @conn.read_u32
length = conn.read_u32
if length > 67_000
raise Exception.new("SigHelper: Packet longer than expected (#{length})")
end
# Payload
data_io = IO::Memory.new(1024)
IO.copy(@conn, data_io, limit: length)
# data = Bytes.new()
# conn.read(data)
return transaction_id, data_io
end
# Write a single packet to the socket
private def write_packet(transaction_id : TransactionID, request : Request)
@conn.write_int(request.opcode)
@conn.write_int(transaction_id)
request.payload.to_io(@conn)
end
end
class Connection
@socket : UNIXSocket | TCPSocket
@mutex = Mutex.new
def initialize(host_or_path : String)
if host_or_path.empty?
host_or_path = default_path
begin
case host_or_path
when.starts_with?('/')
@socket = UNIXSocket.new(host_or_path)
when .starts_with?("tcp://")
uri = URI.new(host_or_path)
@socket = TCPSocket.new(uri.host, uri.port)
else
uri = URI.new("tcp://#{host_or_path}")
@socket = TCPSocket.new(uri.host, uri.port)
end
socket.sync = false
rescue ex
raise ConnectionError.new("Connection error", cause: ex)
end
end
private default_path
return "/tmp/inv_sig_helper.sock"
end
def closed? : Bool
return @socket.closed?
end
def close : Nil
if @socket.closed?
raise Exception.new("SigHelper: Can't close socket, it's already closed")
else
@socket.close
end
end
def gets(*args, **options)
@socket.gets(*args, **options)
end
def read_bytes(*args, **options)
@socket.read_bytes(*args, **options)
end
def write(*args, **options)
@socket.write(*args, **options)
end
def write_bytes(*args, **options)
@socket.write_bytes(*args, **options)
end
end
end