Class: Cosmos::TcpipSocketStream

Inherits:
Stream show all
Defined in:
lib/cosmos/streams/tcpip_socket_stream.rb

Overview

Data Stream which reads and writes from Tcpip Sockets.

Direct Known Subclasses

TcpipClientStream

Constant Summary collapse

FAST_READ = 
(RUBY_VERSION > "2.1")

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(write_socket, read_socket, write_timeout, read_timeout) ⇒ TcpipSocketStream

Returns a new instance of TcpipSocketStream.

Parameters:

  • write_socket (Socket) —

    Socket to write

  • read_socket (Socket) —

    Socket to read

  • write_timeout (Float|nil) —

    Number of seconds to wait for the write to complete or nil to block until the socket is ready to write.

  • read_timeout (Float|nil) —

    Number of seconds to wait for the read to complete or nil to block until the socket is ready to read.



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# File 'lib/cosmos/streams/tcpip_socket_stream.rb', line 39

def initialize(write_socket, read_socket, write_timeout, read_timeout)
  super()

  @write_socket  = write_socket
  @read_socket   = read_socket
  @write_timeout = ConfigParser.handle_nil(write_timeout)
  @write_timeout = @write_timeout.to_f if @write_timeout
  @read_timeout  = ConfigParser.handle_nil(read_timeout)
  @read_timeout  = @read_timeout.to_f if @read_timeout

  # Mutex on write is needed to protect from commands coming in from more
  # than one tool
  @write_mutex = Mutex.new
  @pipe_reader, @pipe_writer = IO.pipe
  @connected = false
end

Instance Attribute Details

#write_socket ⇒ Object (readonly)

Returns the value of attribute write_socket.



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# File 'lib/cosmos/streams/tcpip_socket_stream.rb', line 29

def write_socket
  @write_socket
end

Instance Method Details

#connect ⇒ Object

Connect the stream



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# File 'lib/cosmos/streams/tcpip_socket_stream.rb', line 177

def connect
  # If called directly this class is acting as a server and does not need to connect the sockets
  @connected = true
end

#connected? ⇒ Boolean

Returns Whether the sockets are connected.

Returns:

  • (Boolean) —

    Whether the sockets are connected



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# File 'lib/cosmos/streams/tcpip_socket_stream.rb', line 183

def connected?
  @connected
end

#disconnect ⇒ Object

Disconnect by closing the sockets



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# File 'lib/cosmos/streams/tcpip_socket_stream.rb', line 188

def disconnect
  Cosmos.close_socket(@write_socket)
  Cosmos.close_socket(@read_socket)
  @pipe_writer.write('.')
  @connected = false
end

#read ⇒ String

Returns a binary string of data from the socket

Returns:

  • (String) —

    Returns a binary string of data from the socket



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# File 'lib/cosmos/streams/tcpip_socket_stream.rb', line 57

def read
  raise "Attempt to read from write only stream" unless @read_socket

  # No read mutex is needed because reads happen serially
  if FAST_READ
    begin
      while true # Loop until we get some data
        data = @read_socket.read_nonblock(65535, exception: false)
        raise EOFError, 'end of file reached' unless data

        if data == :wait_readable
          # Wait for the socket to be ready for reading or for the timeout
          begin
            result = IO.fast_select([@read_socket, @pipe_reader], nil, nil, @read_timeout)
            # If select returns something it means the socket is now available for
            # reading so retry the read. If it returns nil it means we timed out.
            # If the pipe is present that means we closed the socket
            if result
              if result.include?(@pipe_reader)
                raise IOError
              else
                next
              end
            else
              raise Timeout::Error, "Read Timeout"
            end
          rescue IOError, Errno::ENOTSOCK
            # These can happen with the socket being closed while waiting on select
            data = ''
          end
        end
        break
      end
    rescue Errno::ECONNRESET, Errno::ECONNABORTED, IOError, Errno::ENOTSOCK
      data = ''
    end
  else
    begin
      data = @read_socket.read_nonblock(65535)
    rescue IO::WaitReadable
      # Wait for the socket to be ready for reading or for the timeout
      begin
        result = IO.fast_select([@read_socket, @pipe_reader], nil, nil, @read_timeout)

        # If select returns something it means the socket is now available for
        # reading so retry the read. If it returns nil it means we timed out.
        # If the pipe is present that means we closed the socket
        if result
          if result.include?(@pipe_reader)
            raise IOError
          else
            retry
          end
        else
          raise Timeout::Error, "Read Timeout"
        end
      rescue IOError, Errno::ENOTSOCK
        # These can happen with the socket being closed while waiting on select
        data = ''
      end
    rescue Errno::ECONNRESET, Errno::ECONNABORTED, IOError, Errno::ENOTSOCK
      data = ''
    end
  end

  data
end

#read_nonblock ⇒ String

Returns a binary string of data from the socket. Always returns immediately

Returns:

  • (String) —

    Returns a binary string of data from the socket. Always returns immediately



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# File 'lib/cosmos/streams/tcpip_socket_stream.rb', line 126

def read_nonblock
  # No read mutex is needed because reads happen serially
  begin
    if FAST_READ
      data = @read_socket.read_nonblock(65535, exception: false)
      raise EOFError, 'end of file reached' unless data

      data = '' if data == :wait_readable
    else
      data = @read_socket.read_nonblock(65535)
    end
  rescue Errno::EAGAIN, Errno::EWOULDBLOCK, Errno::ECONNRESET, Errno::ECONNABORTED, IOError
    data = ''
  end

  data
end

#write(data) ⇒ Object

Parameters:

  • data (String) —

    A binary string of data to write to the socket



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# File 'lib/cosmos/streams/tcpip_socket_stream.rb', line 145

def write(data)
  raise "Attempt to write to read only stream" unless @write_socket

  @write_mutex.synchronize do
    num_bytes_to_send = data.length
    total_bytes_sent = 0
    bytes_sent = 0
    data_to_send = data

    loop do
      begin
        bytes_sent = @write_socket.write_nonblock(data_to_send)
      rescue Errno::EAGAIN, Errno::EWOULDBLOCK
        # Wait for the socket to be ready for writing or for the timeout
        result = IO.fast_select(nil, [@write_socket], nil, @write_timeout)
        # If select returns something it means the socket is now available for
        # writing so retry the write. If it returns nil it means we timed out.
        if result
          retry
        else
          raise Timeout::Error, "Write Timeout"
        end
      end
      total_bytes_sent += bytes_sent
      break if total_bytes_sent >= num_bytes_to_send

      data_to_send = data[total_bytes_sent..-1]
    end
  end
end