Class: Discordrb::Gateway

Inherits:
Object
  • Object
show all
Defined in:
lib/discordrb/gateway.rb

Overview

Client for the Discord gateway protocol

Constant Summary collapse

LARGE_THRESHOLD =

How many members there need to be in a server for it to count as "large"

100
GATEWAY_VERSION =

The version of the gateway that's supposed to be used.

6

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(bot, token, shard_key = nil, compress_mode = :stream) ⇒ Gateway

Returns a new instance of Gateway.


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# File 'lib/discordrb/gateway.rb', line 146

def initialize(bot, token, shard_key = nil, compress_mode = :stream)
  @token = token
  @bot = bot

  @shard_key = shard_key

  # Whether the connection to the gateway has succeeded yet
  @ws_success = false

  @check_heartbeat_acks = true

  @compress_mode = compress_mode
end

Instance Attribute Details

#check_heartbeat_ackstrue, false

Heartbeat ACKs are Discord's way of verifying on the client side whether the connection is still alive. If this is set to true (default value) the gateway client will use that functionality to detect zombie connections and reconnect in such a case; however it may lead to instability if there's some problem with the ACKs. If this occurs it can simply be set to false.

Returns:

  • (true, false)

    whether or not this gateway should check for heartbeat ACKs.


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# File 'lib/discordrb/gateway.rb', line 144

def check_heartbeat_acks
  @check_heartbeat_acks
end

Instance Method Details

#heartbeatObject

Sends a heartbeat with the last received packet's seq (to acknowledge that we have received it and all packets before it), or if none have been received yet, with 0.

See Also:


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# File 'lib/discordrb/gateway.rb', line 248

def heartbeat
  if check_heartbeat_acks
    unless @last_heartbeat_acked
      # We're in a bad situation - apparently the last heartbeat wasn't acked, which means the connection is likely
      # a zombie. Reconnect
      LOGGER.warn('Last heartbeat was not acked, so this is a zombie connection! Reconnecting')

      # We can't send anything on zombie connections
      @pipe_broken = true
      reconnect
      return
    end

    @last_heartbeat_acked = false
  end

  send_heartbeat(@session ? @session.sequence : 0)
end

#identifyObject

Identifies to Discord with the default parameters.

See Also:


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# File 'lib/discordrb/gateway.rb', line 276

def identify
  compress = @compress_mode == :large
  send_identify(@token, {
                  '$os': RUBY_PLATFORM,
                  '$browser': 'discordrb',
                  '$device': 'discordrb',
                  '$referrer': '',
                  '$referring_domain': ''
                }, compress, 100, @shard_key)
end

#inject_error(e) ⇒ Object

Injects a terminal gateway error into the handler. Useful for testing the reconnect logic.

Parameters:

  • e (Exception)

    The exception object to inject.


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# File 'lib/discordrb/gateway.rb', line 241

def inject_error(e)
  handle_internal_close(e)
end

#inject_reconnect(url = nil) ⇒ Object

Injects a reconnect event (op 7) into the event processor, causing Discord to reconnect to the given gateway URL. If the URL is set to nil, it will reconnect and get an entirely new gateway URL. This method has not much use outside of testing and implementing highly custom reconnect logic.

Parameters:

  • url (String, nil) (defaults to: nil)

    the URL to connect to or nil if one should be obtained from Discord.


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# File 'lib/discordrb/gateway.rb', line 221

def inject_reconnect(url = nil)
  # When no URL is specified, the data should be nil, as is the case with Discord-sent packets.
  data = url ? { url: url } : nil

  handle_message({
    op: Opcodes::RECONNECT,
    d: data
  }.to_json)
end

#inject_resume(seq) ⇒ Object

Injects a resume packet (op 6) into the gateway. If this is done with a running connection, it will cause an error. It has no use outside of testing stuff that I know of, but if you want to use it anyway for some reason, here it is.

Parameters:

  • seq (Integer, nil)

    The sequence ID to inject, or nil if the currently tracked one should be used.


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# File 'lib/discordrb/gateway.rb', line 235

def inject_resume(seq)
  send_resume(raw_token, @session_id, seq || @sequence)
end

#killObject

Kills the websocket thread, stopping all connections to Discord.


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# File 'lib/discordrb/gateway.rb', line 207

def kill
  @ws_thread.kill
end

#notify_readyObject

Notifies the #run_async method that everything is ready and the caller can now continue (i.e. with syncing, or with doing processing and then syncing)


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# File 'lib/discordrb/gateway.rb', line 213

def notify_ready
  @ws_success = true
end

#open?Boolean

Whether the WebSocket connection to the gateway is currently open

Returns:

  • (Boolean)

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# File 'lib/discordrb/gateway.rb', line 190

def open?
  @handshake&.finished? && !@closed
end

#reconnect(attempt_resume = true) ⇒ Object

Reconnects the gateway connection in a controlled manner.

Parameters:

  • attempt_resume (true, false) (defaults to: true)

    Whether a resume should be attempted after the reconnection.


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# File 'lib/discordrb/gateway.rb', line 364

def reconnect(attempt_resume = true)
  @session.suspend if @session && attempt_resume

  @instant_reconnect = true
  @should_reconnect = true

  close
end

#resumeObject

Resumes the session from the last recorded point.

See Also:


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# File 'lib/discordrb/gateway.rb', line 358

def resume
  send_resume(@token, @session.session_id, @session.sequence)
end

#run_asyncObject

Connect to the gateway server in a separate thread


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# File 'lib/discordrb/gateway.rb', line 161

def run_async
  @ws_thread = Thread.new do
    Thread.current[:discordrb_name] = 'websocket'
    connect_loop
    LOGGER.warn('The WS loop exited! Not sure if this is a good thing')
  end

  LOGGER.debug('WS thread created! Now waiting for confirmation that everything worked')
  loop do
    sleep(0.5)

    if @ws_success
      LOGGER.debug('Confirmation received! Exiting run.')
      break
    end

    if @should_reconnect == false
      LOGGER.debug('Reconnection flag was unset. Exiting run.')
      break
    end
  end
end

#send_heartbeat(sequence) ⇒ Object

Sends a heartbeat packet (op 1). This tells Discord that the current connection is still active and that the last packets until the given sequence have been processed (in case of a resume).

Parameters:

  • sequence (Integer)

    The sequence number for which to send a heartbeat.


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# File 'lib/discordrb/gateway.rb', line 270

def send_heartbeat(sequence)
  send_packet(Opcodes::HEARTBEAT, sequence)
end

#send_identify(token, properties, compress, large_threshold, shard_key = nil) ⇒ Object

Sends an identify packet (op 2). This starts a new session on the current connection and tells Discord who we are. This can only be done once a connection.

Parameters:

  • token (String)

    The token with which to authorise the session. If it belongs to a bot account, it must be prefixed with "Bot ".

  • properties (Hash<Symbol => String>)

    A list of properties for Discord to use in analytics. The following keys are recognised:

    • "$os" (recommended value: the operating system the bot is running on)
    • "$browser" (recommended value: library name)
    • "$device" (recommended value: library name)
    • "$referrer" (recommended value: empty)
    • "$referring_domain" (recommended value: empty)
  • compress (true, false)

    Whether certain large packets should be compressed using zlib.

  • large_threshold (Integer)

    The member threshold after which a server counts as large and will have to have its member list chunked.

  • shard_key (Array(Integer, Integer), nil) (defaults to: nil)

    The shard key to use for sharding, represented as [shard_id, num_shards], or nil if the bot should not be sharded.


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# File 'lib/discordrb/gateway.rb', line 305

def send_identify(token, properties, compress, large_threshold, shard_key = nil)
  data = {
    # Don't send a v anymore as it's entirely determined by the URL now
    token: token,
    properties: properties,
    compress: compress,
    large_threshold: large_threshold
  }

  # Don't include the shard key at all if it is nil as Discord checks for its mere existence
  data[:shard] = shard_key if shard_key

  send_packet(Opcodes::IDENTIFY, data)
end

#send_packet(opcode, packet) ⇒ Object

Sends a custom packet over the connection. This can be useful to implement future yet unimplemented functionality or for testing. You probably shouldn't use this unless you know what you're doing.

Parameters:

  • opcode (Integer)

    The opcode the packet should be sent as. Can be one of Opcodes or a custom value if necessary.

  • packet (Object)

    Some arbitrary JSON-serialisable data that should be sent as the d field.


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# File 'lib/discordrb/gateway.rb', line 415

def send_packet(opcode, packet)
  data = {
    op: opcode,
    d: packet
  }

  send(data.to_json)
end

#send_raw(data, type = :text) ⇒ Object

Sends custom raw data over the connection. Only useful for testing; even if you know what you're doing you probably want to use #send_packet instead.

Parameters:

  • data (String)

    The data to send.

  • type (Symbol) (defaults to: :text)

    The type the WebSocket frame should have; either :text, :binary, :ping, :pong, or :close.


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# File 'lib/discordrb/gateway.rb', line 429

def send_raw(data, type = :text)
  send(data, type)
end

#send_request_members(server_id, query, limit) ⇒ Object

Sends a request members packet (op 8). This will order Discord to gradually sent all requested members as dispatch events with type GUILD_MEMBERS_CHUNK. It is necessary to use this method in order to get all members of a large server (see large_threshold in #send_identify), however it can also be used for other purposes.

Parameters:

  • server_id (Integer)

    The ID of the server whose members to query.

  • query (String)

    If this string is not empty, only members whose username starts with this string will be returned.

  • limit (Integer)

    How many members to send at maximum, or 0 to send all members.


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# File 'lib/discordrb/gateway.rb', line 400

def send_request_members(server_id, query, limit)
  data = {
    guild_id: server_id,
    query: query,
    limit: limit
  }

  send_packet(Opcodes::REQUEST_MEMBERS, data)
end

#send_resume(token, session_id, seq) ⇒ Object

Sends a resume packet (op 6). This replays all events from a previous point specified by its packet sequence. This will not work if the packet to resume from has already been acknowledged using a heartbeat, or if the session ID belongs to a now invalid session.

If this packet is sent at the beginning of a connection, it will act similarly to an #identify in that it creates a session on the current connection. Unlike identify however, this packet can also be sent in an existing session and will just replay some of the events.

Parameters:

  • token (String)

    The token that was used to identify the session to resume.

  • session_id (String)

    The session ID of the session to resume.

  • seq (Integer)

    The packet sequence of the packet after which the events should be replayed.


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# File 'lib/discordrb/gateway.rb', line 383

def send_resume(token, session_id, seq)
  data = {
    token: token,
    session_id: session_id,
    seq: seq
  }

  send_packet(Opcodes::RESUME, data)
end

#send_status_update(status, since, game, afk) ⇒ Object

Sends a status update packet (op 3). This sets the bot user's status (online/idle/...) and game playing/streaming.

Parameters:

  • status (String)

    The status that should be set (online, idle, dnd, invisible).

  • since (Integer)

    The unix timestamp in milliseconds when the status was set. Should only be provided when afk is true.

  • game (Hash<Symbol => Object>, nil)

    nil if no game should be played, or a hash of :game => "name" if a game should be played. The hash can also contain additional attributes for streaming statuses.

  • afk (true, false)

    Whether the status was set due to inactivity on the user's part.


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# File 'lib/discordrb/gateway.rb', line 327

def send_status_update(status, since, game, afk)
  data = {
    status: status,
    since: since,
    game: game,
    afk: afk
  }

  send_packet(Opcodes::PRESENCE, data)
end

#send_voice_state_update(server_id, channel_id, self_mute, self_deaf) ⇒ Object

Sends a voice state update packet (op 4). This packet can connect a user to a voice channel, update self mute/deaf status in an existing voice connection, move the user to a new voice channel on the same server or disconnect an existing voice connection.

Parameters:

  • server_id (Integer)

    The ID of the server on which this action should occur.

  • channel_id (Integer, nil)

    The channel ID to connect/move to, or nil to disconnect.

  • self_mute (true, false)

    Whether the user should itself be muted to everyone else.

  • self_deaf (true, false)

    Whether the user should be deaf towards other users.


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# File 'lib/discordrb/gateway.rb', line 345

def send_voice_state_update(server_id, channel_id, self_mute, self_deaf)
  data = {
    guild_id: server_id,
    channel_id: channel_id,
    self_mute: self_mute,
    self_deaf: self_deaf
  }

  send_packet(Opcodes::VOICE_STATE, data)
end

#stopObject

Stops the bot gracefully, disconnecting the websocket without immediately killing the thread. This means that Discord is immediately aware of the closed connection and makes the bot appear offline instantly.

If this method doesn't work or you're looking for something more drastic, use #kill instead.


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# File 'lib/discordrb/gateway.rb', line 198

def stop
  @should_reconnect = false
  close

  # Return nil so command bots don't send a message
  nil
end

#syncObject

Prevents all further execution until the websocket thread stops (e.g. through a closed connection).


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# File 'lib/discordrb/gateway.rb', line 185

def sync
  @ws_thread.join
end