Class: FTW::WebSocket::Writer

Inherits:
Object
  • Object
show all
Extended by:
Singleton
Includes:
Constants
Defined in:
lib/ftw/websocket/writer.rb

Overview

This class implements a writer for WebSocket messages over a stream.

Protocol diagram copied from RFC6455

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-------+-+-------------+-------------------------------+
|F|R|R|R| opcode|M| Payload len |    Extended payload length    |
|I|S|S|S|  (4)  |A|     (7)     |             (16/64)           |
|N|V|V|V|       |S|             |   (if payload len==126/127)   |
| |1|2|3|       |K|             |                               |
+-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
|     Extended payload length continued, if payload len == 127  |
+ - - - - - - - - - - - - - - - +-------------------------------+
|                               |Masking-key, if MASK set to 1  |
+-------------------------------+-------------------------------+
| Masking-key (continued)       |          Payload Data         |
+-------------------------------- - - - - - - - - - - - - - - - +
:                     Payload Data continued ...                :
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
|                     Payload Data continued ...                |
+---------------------------------------------------------------+

Constant Summary collapse

VALID_MODES =

A list of valid modes. Used to validate input in #write_text.

In :server mode, payloads are not masked. In :client mode, payloads are masked. Masking is described in RFC6455.

[:server, :client]

Constants included from Constants

Constants::OPCODE_BINARY, Constants::OPCODE_CLOSE, Constants::OPCODE_CONTINUATION, Constants::OPCODE_PING, Constants::OPCODE_PONG, Constants::OPCODE_TEXT, Constants::WEBSOCKET_ACCEPT_UUID

Instance Method Summary collapse

Methods included from Singleton

included, singleton

Instance Method Details

#write_text(connection, text, mode = :server) ⇒ Object

Write the given text in a websocket frame to the connection.

Valid ‘mode’ settings are :server or :client. If :client, the payload will be masked according to RFC6455 section 5.3: tools.ietf.org/html/rfc6455#section-5.3



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# File 'lib/ftw/websocket/writer.rb', line 45

def write_text(connection, text, mode=:server)
  if !VALID_MODES.include?(mode)
    raise InvalidArgument.new("Invalid message mode: #{mode}, expected one of" \
                              "#{VALID_MODES.inspect}")
  end

  data = []
  pack = []

  # For now, assume single-fragment, text frames
  pack_opcode(data, pack, OPCODE_TEXT)
  pack_payload(data, pack, text, mode)
  connection.write(data.pack(pack.join("")))
end