Module: Net::SSH::BufferedIo

Module | Net::SSH::BufferedIo
In: | lib/net/ssh/buffered_io.rb

This module is used to extend sockets and other IO objects, to allow them to be buffered for both read and write. This abstraction makes it quite easy to write a select-based event loop (see Net::SSH::Connection::Session#listen_to).

The general idea is that instead of calling read directly on an IO that has been extended with this module, you call fill (to add pending input to the internal read buffer), and then read_available (to read from that buffer). Likewise, you don‘t call write directly, you call enqueue to add data to the write buffer, and then send_pending or wait_for_pending_sends to actually send the data across the wire.

In this way you can easily use the object as an argument to IO.select, calling fill when it is available for read, or send_pending when it is available for write, and then call enqueue and read_available during the idle times.

      socket = TCPSocket.new(address, port)
      socket.extend(Net::SSH::BufferedIo)

      ssh.listen_to(socket)

      ssh.loop do
        if socket.available > 0
          puts socket.read_available
          socket.enqueue("response\n")
        end
      end

Note that this module must be used to extend an instance, and should not be included in a class. If you do want to use it via an include, then you must make sure to invoke the private initialize_buffered_io method in your class’ initialize method:

      class Foo < IO
        include Net::SSH::BufferedIo

        def initialize
          initialize_buffered_io
          # ...
        end
      end

### Methods

available enqueue fill pending_write? read_available send_pending wait_for_pending_sends

### Included Modules

Loggable

### Public Instance methods

available()

Returns the number of bytes available to be read from the input buffer. (See read_available.)

enqueue(data)

Enqueues data in the output buffer, to be written when send_pending is called. Note that the data is not sent immediately by this method!

fill(n=8192)

Tries to read up to `n` bytes of data from the remote end, and appends the data to the input buffer. It returns the number of bytes read, or 0 if no data was available to be read.

pending_write?()

Returns `true` if there is data waiting in the output buffer, and `false` otherwise.

read_available(length=nil)

Read up to `length` bytes from the input buffer. If `length` is nil, all available data is read from the buffer. (See available.)

send_pending()

Sends as much of the pending output as possible. Returns `true` if any data was sent, and `false` otherwise.

wait_for_pending_sends()

Calls send_pending repeatedly, if necessary, blocking until the output buffer is empty.

[Validate]