Remove signature helper completely from Invidious

The official way to reproduce video with Invidious now is by using
Invidious Companion which uses Youtube.JS with a Javascript Interpreter
that can successfully decrypt youtube video URLs.

Sig helper has not been used for a long time, is beyond broken and no
one has plans to fix it and maintain it.

config/config.example.yml

@@ -40,20 +40,6 @@ db:
 ##
 #check_tables: false
 
-
-##
-## Path to an external signature resolver, used to emulate
-## the Youtube client's Javascript. If no such server is
-## available, some videos will not be playable.
-##
-## When this setting is commented out, no external
-## resolver will be used.
-##
-## Accepted values: a path to a UNIX socket or "<IP>:<Port>"
-## Default: <none>
-##
-#signature_server:
-
 ##
 ## Invidious companion is an external program
 ## for loading the video streams from YouTube servers.
@@ -259,19 +245,6 @@ https_only: false
 ##
 # use_innertube_for_captions: false
 
-##
-## Send Google session informations. This is useful when Invidious is blocked
-## by the message "This helps protect our community."
-## See https://github.com/iv-org/invidious/issues/4734.
-##
-## Warning: These strings gives much more identifiable information to Google!
-##
-## Accepted values: String
-## Default: <none>
-##
-# po_token: ""
-# visitor_data: ""
-
 # -----------------------------
 #  Logging
 # -----------------------------

src/invidious.cr

@@ -172,12 +172,7 @@ Invidious::Database.check_integrity(CONFIG)
 
 # Misc
 
-DECRYPT_FUNCTION =
+DECRYPT_FUNCTION = nil
-  if sig_helper_address = CONFIG.signature_server.presence
-    IV::DecryptFunction.new(sig_helper_address)
-  else
-    nil
-  end
 
 # Start jobs
 

src/invidious/config.cr

@@ -153,9 +153,6 @@ class Config
   @[YAML::Field(converter: Preferences::FamilyConverter)]
   property force_resolve : Socket::Family = Socket::Family::UNSPEC
 
-  # External signature solver server socket (either a path to a UNIX domain socket or "<IP>:<Port>")
-  property signature_server : String? = nil
-
   # Port to listen for connections (overridden by command line argument)
   property port : Int32 = 3000
   # Host to bind (overridden by command line argument)
@@ -170,11 +167,6 @@ class Config
   # Use Innertube's transcripts API instead of timedtext for closed captions
   property use_innertube_for_captions : Bool = false
 
-  # visitor data ID for Google session
-  property visitor_data : String? = nil
-  # poToken for passing bot attestation
-  property po_token : String? = nil
-
   # Invidious companion
   property invidious_companion : Array(CompanionConfig) = [] of CompanionConfig
 
@@ -262,11 +254,7 @@ class Config
     {% end %}
 
     if config.invidious_companion.present?
-      # invidious_companion and signature_server can't work together
+      if config.invidious_companion_key.empty?
-      if config.signature_server
-        puts "Config: You can not run inv_sig_helper and invidious_companion at the same time."
-        exit(1)
-      elsif config.invidious_companion_key.empty?
         puts "Config: Please configure a key if you are using invidious companion."
         exit(1)
       elsif config.invidious_companion_key == "CHANGE_ME!!"
@@ -284,8 +272,6 @@ class Config
           companion.builtin_proxy = true
         end
       end
-    elsif config.signature_server
-      puts("WARNING: inv-sig-helper is deprecated. Please switch to Invidious companion: https://docs.invidious.io/installation/")
     else
       puts("WARNING: Invidious companion is required to view and playback videos. For more information see https://docs.invidious.io/installation/")
     end

src/invidious/helpers/sig_helper.cr

@@ -1,349 +0,0 @@
-require "uri"
-require "socket"
-require "socket/tcp_socket"
-require "socket/unix_socket"
-
-{% if flag?(:advanced_debug) %}
-  require "io/hexdump"
-{% end %}
-
-private alias NetworkEndian = IO::ByteFormat::NetworkEndian
-
-module Invidious::SigHelper
-  enum UpdateStatus
-    Updated
-    UpdateNotRequired
-    Error
-  end
-
-  # -------------------
-  #  Payload types
-  # -------------------
-
-  abstract struct Payload
-  end
-
-  struct StringPayload < Payload
-    getter string : String
-
-    def initialize(str : String)
-      raise Exception.new("SigHelper: String can't be empty") if str.empty?
-      @string = str
-    end
-
-    def self.from_bytes(slice : Bytes)
-      size = IO::ByteFormat::NetworkEndian.decode(UInt16, slice)
-      if size == 0 # Error code
-        raise Exception.new("SigHelper: Server encountered an error")
-      end
-
-      if (slice.bytesize - 2) != size
-        raise Exception.new("SigHelper: String size mismatch")
-      end
-
-      if str = String.new(slice[2..])
-        return self.new(str)
-      else
-        raise Exception.new("SigHelper: Can't read string from socket")
-      end
-    end
-
-    def to_io(io)
-      # `.to_u16` raises if there is an overflow during the conversion
-      io.write_bytes(@string.bytesize.to_u16, NetworkEndian)
-      io.write(@string.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
-    PLAYER_UPDATE_TIMESTAMP = 5
-  end
-
-  private record Request,
-    opcode : Opcode,
-    payload : Payload?
-
-  # ----------------------
-  #  High-level functions
-  # ----------------------
-
-  class Client
-    @mux : Multiplexor
-
-    def initialize(uri_or_path)
-      @mux = Multiplexor.new(uri_or_path)
-    end
-
-    # 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 |bytes|
-        IO::ByteFormat::NetworkEndian.decode(UInt16, bytes)
-      end
-
-      case value
-      when 0x0000 then return UpdateStatus::Error
-      when 0xFFFF then return UpdateStatus::UpdateNotRequired
-      when 0xF44F then return UpdateStatus::Updated
-      else
-        code = value.nil? ? "nil" : value.to_s(base: 16)
-        raise Exception.new("SigHelper: Invalid status code received #{code}")
-      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 = self.send_request(request) do |bytes|
-        StringPayload.from_bytes(bytes).string
-      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 = self.send_request(request) do |bytes|
-        StringPayload.from_bytes(bytes).string
-      end
-
-      return sig_dec
-    end
-
-    # Return the signature timestamp from the server's current player
-    def get_signature_timestamp : UInt64?
-      request = Request.new(Opcode::GET_SIGNATURE_TIMESTAMP, nil)
-
-      return self.send_request(request) do |bytes|
-        IO::ByteFormat::NetworkEndian.decode(UInt64, bytes)
-      end
-    end
-
-    # Return the current player's version
-    def get_player : UInt32?
-      request = Request.new(Opcode::GET_PLAYER_STATUS, nil)
-
-      return self.send_request(request) do |bytes|
-        has_player = (bytes[0] == 0xFF)
-        player_version = IO::ByteFormat::NetworkEndian.decode(UInt32, bytes[1..4])
-        has_player ? player_version : nil
-      end
-    end
-
-    # Return when the player was last updated
-    def get_player_timestamp : UInt64?
-      request = Request.new(Opcode::PLAYER_UPDATE_TIMESTAMP, nil)
-
-      return self.send_request(request) do |bytes|
-        IO::ByteFormat::NetworkEndian.decode(UInt64, bytes)
-      end
-    end
-
-    private def send_request(request : Request, &)
-      channel = @mux.send(request)
-      slice = channel.receive
-      return yield slice
-    rescue ex
-      LOGGER.debug("SigHelper: Error when sending a request")
-      LOGGER.trace(ex.inspect_with_backtrace)
-      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
-    @uri_or_path : String
-
-    def initialize(@uri_or_path)
-      @conn = Connection.new(uri_or_path)
-      listen
-    end
-
-    def listen : Nil
-      raise "Socket is closed" if @conn.closed?
-
-      LOGGER.debug("SigHelper: Multiplexor listening")
-
-      spawn do
-        loop do
-          begin
-            receive_data
-          rescue ex
-            LOGGER.info("SigHelper: Connection to helper died with '#{ex.message}' trying to reconnect...")
-            # We close the socket because for some reason is not closed.
-            @conn.close
-            loop do
-              begin
-                @conn = Connection.new(@uri_or_path)
-                LOGGER.info("SigHelper: Reconnected to SigHelper!")
-              rescue ex
-                LOGGER.debug("SigHelper: Reconnection to helper unsuccessful with error '#{ex.message}'. Retrying")
-                sleep 500.milliseconds
-                next
-              end
-              break if !@conn.closed?
-            end
-          end
-          Fiber.yield
-        end
-      end
-    end
-
-    def send(request : Request)
-      transaction = Transaction.new
-      transaction_id = @prng.rand(TransactionID)
-
-      # Add transaction to queue
-      @mutex.synchronize do
-        # On a 32-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
-      transaction_id, slice = read_packet
-
-      @mutex.synchronize do
-        if transaction = @queue.delete(transaction_id)
-          # Remove transaction from queue and send data to the channel
-          transaction.channel.send(slice)
-          LOGGER.trace("SigHelper: Transaction unqueued and data sent to channel")
-        else
-          raise Exception.new("SigHelper: Received transaction was not in queue")
-        end
-      end
-    end
-
-    # Read a single packet from the socket
-    private def read_packet : {TransactionID, Bytes}
-      # Header
-      transaction_id = @conn.read_bytes(UInt32, NetworkEndian)
-      length = @conn.read_bytes(UInt32, NetworkEndian)
-
-      LOGGER.trace("SigHelper: Recv transaction 0x#{transaction_id.to_s(base: 16)} / length #{length}")
-
-      if length > 67_000
-        raise Exception.new("SigHelper: Packet longer than expected (#{length})")
-      end
-
-      # Payload
-      slice = Bytes.new(length)
-      @conn.read(slice) if length > 0
-
-      LOGGER.trace("SigHelper: payload = #{slice}")
-      LOGGER.trace("SigHelper: Recv transaction 0x#{transaction_id.to_s(base: 16)} - Done")
-
-      return transaction_id, slice
-    end
-
-    # Write a single packet to the socket
-    private def write_packet(transaction_id : TransactionID, request : Request)
-      LOGGER.trace("SigHelper: Send transaction 0x#{transaction_id.to_s(base: 16)} / opcode #{request.opcode}")
-
-      io = IO::Memory.new(1024)
-      io.write_bytes(request.opcode.to_u8, NetworkEndian)
-      io.write_bytes(transaction_id, NetworkEndian)
-
-      if payload = request.payload
-        payload.to_io(io)
-      end
-
-      @conn.send(io)
-      @conn.flush
-
-      LOGGER.trace("SigHelper: Send transaction 0x#{transaction_id.to_s(base: 16)} - Done")
-    end
-  end
-
-  class Connection
-    @socket : UNIXSocket | TCPSocket
-
-    {% if flag?(:advanced_debug) %}
-      @io : IO::Hexdump
-    {% end %}
-
-    def initialize(host_or_path : String)
-      case host_or_path
-      when .starts_with?('/')
-        # Make sure that the file exists
-        if File.exists?(host_or_path)
-          @socket = UNIXSocket.new(host_or_path)
-        else
-          raise Exception.new("SigHelper: '#{host_or_path}' no such file")
-        end
-      when .starts_with?("tcp://")
-        uri = URI.parse(host_or_path)
-        @socket = TCPSocket.new(uri.host.not_nil!, uri.port.not_nil!)
-      else
-        uri = URI.parse("tcp://#{host_or_path}")
-        @socket = TCPSocket.new(uri.host.not_nil!, uri.port.not_nil!)
-      end
-      LOGGER.info("SigHelper: Using helper at '#{host_or_path}'")
-
-      {% if flag?(:advanced_debug) %}
-        @io = IO::Hexdump.new(@socket, output: STDERR, read: true, write: true)
-      {% end %}
-
-      @socket.sync = false
-      @socket.blocking = false
-    end
-
-    def closed? : Bool
-      return @socket.closed?
-    end
-
-    def close : Nil
-      @socket.close if !@socket.closed?
-    end
-
-    def flush(*args, **options)
-      @socket.flush(*args, **options)
-    end
-
-    def send(*args, **options)
-      @socket.send(*args, **options)
-    end
-
-    # Wrap IO functions, with added debug tooling if needed
-    {% for function in %w(read read_bytes write write_bytes) %}
-      def {{function.id}}(*args, **options)
-        {% if flag?(:advanced_debug) %}
-          @io.{{function.id}}(*args, **options)
-        {% else %}
-          @socket.{{function.id}}(*args, **options)
-        {% end %}
-      end
-    {% end %}
-  end
-end

src/invidious/helpers/signatures.cr

@@ -1,53 +0,0 @@
-require "http/params"
-require "./sig_helper"
-
-class Invidious::DecryptFunction
-  @last_update : Time = Time.utc - 42.days
-
-  def initialize(uri_or_path)
-    @client = SigHelper::Client.new(uri_or_path)
-    self.check_update
-  end
-
-  def check_update
-    # If we have updated in the last 5 minutes, do nothing
-    return if (Time.utc - @last_update) < 5.minutes
-
-    # Get the amount of time elapsed since when the player was updated, in the
-    # event where multiple invidious processes are run in parallel.
-    update_time_elapsed = (@client.get_player_timestamp || 301).seconds
-
-    if update_time_elapsed > 5.minutes
-      LOGGER.debug("Signature: Player might be outdated, updating")
-      @client.force_update
-      @last_update = Time.utc
-    end
-  end
-
-  def decrypt_nsig(n : String) : String?
-    self.check_update
-    return @client.decrypt_n_param(n)
-  rescue ex
-    LOGGER.debug(ex.message || "Signature: Unknown error")
-    LOGGER.trace(ex.inspect_with_backtrace)
-    return nil
-  end
-
-  def decrypt_signature(str : String) : String?
-    self.check_update
-    return @client.decrypt_sig(str)
-  rescue ex
-    LOGGER.debug(ex.message || "Signature: Unknown error")
-    LOGGER.trace(ex.inspect_with_backtrace)
-    return nil
-  end
-
-  def get_sts : UInt64?
-    self.check_update
-    return @client.get_signature_timestamp
-  rescue ex
-    LOGGER.debug(ex.message || "Signature: Unknown error")
-    LOGGER.trace(ex.inspect_with_backtrace)
-    return nil
-  end
-end

src/invidious/videos/parser.cr

@@ -491,10 +491,6 @@ private def convert_url(fmt)
   n = DECRYPT_FUNCTION.try &.decrypt_nsig(params["n"])
   params["n"] = n if n
 
-  if token = CONFIG.po_token
-    params["pot"] = token
-  end
-
   url.query_params = params
   LOGGER.trace("convert_url: new url is '#{url}'")
 

src/invidious/yt_backend/youtube_api.cr

@@ -335,10 +335,6 @@ module YoutubeAPI
       client_context["client"]["platform"] = platform
     end
 
-    if CONFIG.visitor_data.is_a?(String)
-      client_context["client"]["visitorData"] = CONFIG.visitor_data.as(String)
-    end
-
     return client_context
   end
 
@@ -496,9 +492,6 @@ module YoutubeAPI
       "playbackContext" => {
         "contentPlaybackContext" => playback_ctx,
       },
-      "serviceIntegrityDimensions" => {
-        "poToken" => CONFIG.po_token,
-      },
     }
 
     # Append the additional parameters if those were provided
@@ -635,10 +628,6 @@ module YoutubeAPI
       headers["User-Agent"] = user_agent
     end
 
-    if CONFIG.visitor_data.is_a?(String)
-      headers["X-Goog-Visitor-Id"] = CONFIG.visitor_data.as(String)
-    end
-
     # Logging
     LOGGER.debug("YoutubeAPI: Using endpoint: \"#{endpoint}\"")
     LOGGER.trace("YoutubeAPI: ClientConfig: #{client_config}")