Class: SDN::Client

Inherits:
Object
  • Object
show all
Defined in:
lib/sdn/client.rb

Overview

Transport client for sending and receiving SDN frames over serial, TCP, RFC2217, or PTY.

Constant Summary collapse

WAIT_TIME =

Default inter-read wait time, in seconds, while assembling a partial frame.

0.25

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(port) ⇒ Client

Opens a connection to an SDN bus over serial, TCP, RFC2217, or PTY.

Parameters:

  • port (String) —

    connection target URI or serial device path



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# File 'lib/sdn/client.rb', line 16

def initialize(port)
  uri = URI.parse(port)
  @io = if uri.scheme == "tcp"
          require "socket"
          TCPSocket.new(uri.host, uri.port)
        elsif %w[telnet rfc2217].include?(uri.scheme)
          require "net/telnet/rfc2217"
          Net::Telnet::RFC2217.new(host: uri.host,
                                   port: uri.port || 23,
                                   baud: 4800,
                                   data_bits: 8,
                                   parity: :odd,
                                   stop_bits: 1)
        elsif port == "/dev/ptmx"
          require "pty"
          io, slave = PTY.open
          puts "Slave PTY available at #{slave.path}"
          io
        elsif uri.scheme == "esphome"
          gem "esphome", "~> 1.1"
          require "esphome/serial_proxy"
          ESPHome::SerialProxy.open(uri, baud: 4800, data_bits: 8, parity: :odd, stop_bits: 1)
        else
          require "ccutrer-serialport"
          CCutrer::SerialPort.new(port, baud: 4800, data_bits: 8, parity: :odd, stop_bits: 1)
        end
  @buffer = +""
end

Instance Attribute Details

#trace=(value) ⇒ true, false (writeonly)

Enables or disables raw byte tracing in the client logs.

Returns:

  • (true, false) 


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# File 'lib/sdn/client.rb', line 11

def trace=(value)
  @trace = value
end

Instance Method Details

#ensure(message) ⇒ SDN::Message

Re-sends a request until an expected response is received.

The expected response message is dependent on the message sent.

Parameters:

Returns:

  • (SDN::Message) —

    the message that is of the expected response type



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# File 'lib/sdn/client.rb', line 80

def ensure(message)
  loop do
    messages = transact(message)
    next if messages.empty?
    next unless message.class.expected_response?(messages.first)

    return messages.first
  end
end

#receive(timeout = nil) {|message| ... } ⇒ <SDN::Message>

Reads and parses messages from the transport until parsing is exhausted or a timeout occurs.

Parameters:

  • timeout (Numeric, nil) (defaults to: nil) —

    optional read timeout in seconds

Yields:

  • (message) —

    yields each parsed message when a block is given

Yield Parameters:

Returns:

  • (<SDN::Message>) —

    parsed messages when no block is given



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# File 'lib/sdn/client.rb', line 101

def receive(timeout = nil)
  messages = []

  loop do
    message, bytes_read = Message.parse(@buffer.bytes)
    # discard how much we read
    @buffer = @buffer[bytes_read..] if bytes_read
    unless message
      break unless messages.empty?

      # one EOF is just serial ports saying they have no data;
      # several EOFs in a row is the file is dead and gone
      eofs = 0
      begin
        block = @io.read_nonblock(64 * 1024)
        SDN.logger.debug("Read #{block.unpack1("H*").gsub(/\h{2}/, "\\0 ")}") if trace?
        @buffer.concat(block)
        next
      rescue IO::WaitReadable, EOFError => e
        if e.is_a?(EOFError)
          eofs += 1
        else
          eofs = 0
        end
        raise if eofs == 5

        wait = @buffer.empty? ? timeout : WAIT_TIME
        if @io.wait_readable(wait).nil?
          # timed out; just discard everything
          unless @buffer.empty?
            SDN.logger.debug "Discarding #{@buffer.unpack1("H*").gsub(/\h{2}/, "\\0 ")} due to timeout"
          end
          @buffer = +""
          return messages if timeout
        end

        retry
      end
      next
    end

    SDN.logger.debug("Received message #{message.inspect}")
    if block_given?
      yield message
    else
      messages << message
    end
  end

  messages
end

#send(message) ⇒ void

This method returns an undefined value.

Serializes and writes a message to the underlying transport.

Parameters:



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# File 'lib/sdn/client.rb', line 57

def send(message)
  SDN.logger.debug("Sending #{message.inspect}")
  @io.write(message.serialize)
end

#trace? ⇒ true, false

Indicates whether raw byte tracing is enabled.

Returns:

  • (true, false) 


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# File 'lib/sdn/client.rb', line 48

def trace?
  @trace
end

#transact(message) ⇒ <SDN::Message>

Sends a message with acknowledgement requested and waits for an initial response batch.

Parameters:

Returns:



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# File 'lib/sdn/client.rb', line 67

def transact(message)
  message.ack_requested = true
  send(message)
  receive(1)
end