module BBS::Telnet::Keys

Key input of a telnet line: control bytes and UTF-8 characters decoded into Strings and Symbols (readkey; Telnet::Escapes decodes the escape sequences of the special keys), and raw bytes for binary protocols (read_raw_byte).

Constants

CONTROL_KEYS: The control bytes that are keys of their own; the other Ctrl-letters are :ctrl_<letter>.
CTRL_LETTERS: The control bytes Ctrl-A … Ctrl-Z.
CTRL_TO_LETTER: Added to a Ctrl-letter byte, gives its lowercase letter.
ESC_WAIT: Seconds to wait for the rest of an escape sequence (or UTF-8 character) before a lone ESC counts as the Escape key.
UTF8_LEAD: The bytes that start a multibyte UTF-8 character.
UTF8_LEAD_3: The lowest lead byte of a three-byte UTF-8 character.
UTF8_LEAD_4: The lowest lead byte of a four-byte UTF-8 character.
UTF8_TAIL: The value of those bits in a continuation byte.
UTF8_TAIL_MASK: The bits that tell a UTF-8 continuation byte.

Public Instance Methods

read_raw_byte (timeout)

Source

# File lib/bbs/telnet/keys.rb, line 61
def read_raw_byte(timeout)
  loop do
    raw = read_byte(timeout)
    return raw unless raw.is_a?(String)

    byte = telnet_data(raw.ord)
    return byte if byte
  end
end

Reads one byte of the line as an Integer, for binary protocols (ZMODEM): telnet commands are taken out and a doubled IAC comes back as 255. Returns :timeout when nothing came within timeout seconds and nil on hangup.

readkey (timeout: nil)

Source

# File lib/bbs/telnet/keys.rb, line 46
def readkey(timeout: nil)
  loop do
    raw = read_byte(timeout)
    return :idle if raw == :timeout
    return nil if raw.nil?

    key = key_of(raw)
    return key if key
  end
end

Reads one key press, skipping telnet commands (a NAWS report among them updates the window size). Returns:

a one-character String for a printable character (UTF-8 included),
a Symbol for a special key: :enter, :tab, :backspace, :escape, :interrupt (Ctrl-C), :ctrl_a … :ctrl_z, arrows, :home, :end, :page_up, :f1 … :f12 and the like, with an alt_, shift_, ctrl_ or ctrl_shift_ prefix for modified keys,
a MouseEvent for a mouse report,
:idle when nothing came within timeout seconds,
nil when the client hung up.

On a PETSCII line the keys come from BBS::Petscii.key. CR LF and CR NUL count as one :enter. timeout nil waits forever.