Module | Net::SSH::BufferedIo |
In: |
lib/net/ssh/buffered_io.rb
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
Returns the number of bytes available to be read from the input buffer. (See read_available.)
# File lib/net/ssh/buffered_io.rb, line 78 78: def available 79: input.available 80: end
Returns the number of bytes available to be read from the input buffer. (See read_available.)
# File lib/net/ssh/buffered_io.rb, line 78 78: def available 79: input.available 80: end
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!
# File lib/net/ssh/buffered_io.rb, line 84 84: def enqueue(data) 85: output.append(data) 86: end
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!
# File lib/net/ssh/buffered_io.rb, line 84 84: def enqueue(data) 85: output.append(data) 86: end
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.
# File lib/net/ssh/buffered_io.rb, line 62 62: def fill(n=8192) 63: input.consume! 64: data = recv(n) 65: debug { "read #{data.length} bytes" } 66: input.append(data) 67: return data.length 68: end
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.
# File lib/net/ssh/buffered_io.rb, line 62 62: def fill(n=8192) 63: input.consume! 64: data = recv(n) 65: debug { "read #{data.length} bytes" } 66: input.append(data) 67: return data.length 68: end
Returns true if there is data waiting in the output buffer, and false otherwise.
# File lib/net/ssh/buffered_io.rb, line 90 90: def pending_write? 91: output.length > 0 92: end
Returns true if there is data waiting in the output buffer, and false otherwise.
# File lib/net/ssh/buffered_io.rb, line 90 90: def pending_write? 91: output.length > 0 92: end
Sends as much of the pending output as possible. Returns true if any data was sent, and false otherwise.
# File lib/net/ssh/buffered_io.rb, line 96 96: def send_pending 97: if output.length > 0 98: sent = send(output.to_s, 0) 99: debug { "sent #{sent} bytes" } 100: output.consume!(sent) 101: return sent > 0 102: else 103: return false 104: end 105: end
Sends as much of the pending output as possible. Returns true if any data was sent, and false otherwise.
# File lib/net/ssh/buffered_io.rb, line 96 96: def send_pending 97: if output.length > 0 98: sent = send(output.to_s, 0) 99: debug { "sent #{sent} bytes" } 100: output.consume!(sent) 101: return sent > 0 102: else 103: return false 104: end 105: end
Calls send_pending repeatedly, if necessary, blocking until the output buffer is empty.
# File lib/net/ssh/buffered_io.rb, line 109 109: def wait_for_pending_sends 110: send_pending 111: while output.length > 0 112: result = IO.select(nil, [self]) or next 113: next unless result[1].any? 114: send_pending 115: end 116: end
Calls send_pending repeatedly, if necessary, blocking until the output buffer is empty.
# File lib/net/ssh/buffered_io.rb, line 109 109: def wait_for_pending_sends 110: send_pending 111: while output.length > 0 112: result = IO.select(nil, [self]) or next 113: next unless result[1].any? 114: send_pending 115: end 116: end