class BBS::Server

The telnet listener. It accepts connections on a TCP port and runs a BBS::Session for each caller in its own thread, up to BBS.config.max_sessions callers at once and BBS.config.max_sessions_per_ip from one public address.

BBS::Server.new(port: 2323).run

Constants

ACCEPT_PAUSE: Seconds the accept loop rests after a failed accept (out of file descriptors and the like).
BACKTRACE_LINES: Lines of the backtrace logged with a session error.
DEFAULT_TIMEOUT: Seconds a silent line may stay connected when BBS.config.idle_seconds is not set.
REFUSALS: What a caller turned away hears, by the verdict of admit.

Public Class Methods

new (port:)

Source

# File lib/bbs/server.rb, line 29
def initialize(port:)
  @port     = port
  @mu       = Mutex.new
  @sessions = 0
  @calls    = Hash.new(0)
end

Creates a server that will listen on port on all interfaces. Nothing is opened until run.

Public Instance Methods

admit (address)

Source

# File lib/bbs/server.rb, line 65
def admit(address)
  @mu.synchronize do
    return :busy if @sessions >= BBS.config.max_sessions
    return :crowded if crowded?(address)

    @sessions += 1
    @calls[address] += 1
    :ok
  end
end

Takes a call from the IP address (a String, nil when unknown) when there is room, and counts it. Returns the verdict:

:ok: admitted; release must follow when the call ends
:busy: BBS.config.max_sessions callers are on
:crowded: BBS.config.max_sessions_per_ip calls come from this address already; a local one (a proxy such as bbs-web on the Docker network, see BBS::Address.local?) or an unknown one has no such limit

release (address)

Source

# File lib/bbs/server.rb, line 77
def release(address)
  @mu.synchronize do
    @sessions -= 1
    @calls[address] -= 1
    @calls.delete(address) unless @calls[address].positive?
  end
end

Ends the count of a call admit took from address.

run ()

Source

# File lib/bbs/server.rb, line 45
def run
  server = TCPServer.new('0.0.0.0', @port)
  puts "BBS listening on port #{@port} — connect with: telnet localhost #{@port}"
  stop_on_term
  loop { serve(accept(server)) }
rescue Interrupt
  puts "\nServer stopped."
ensure
  server&.close
end

Opens the port and serves callers until the process is interrupted (Ctrl-C) or stopped (SIGTERM, as docker stop sends). Blocks the calling thread.

Each accepted connection gets an idle timeout and a BBS::Session in a new thread. A caller admit refuses hears why and is disconnected. Session errors are logged and end only that session; BBS.config.on_session_end is called with the session when it finishes. On a stop it prints “Server stopped.” and returns.