block.py

from tornado.ioloop import IOLoop
from tornado.tcpserver import TCPServer
from tornado import gen
from tornado.iostream import StreamClosedError


BUFFER = 4*1024

async def handler(stream):
    await stream.read_until(b'VER 1 AUTH', max_bytes=10)
    auth = await stream.read_until(b'CMD', max_bytes=40)
    auth_string = auth.decode('ASCII')
    auth_type, token, _ = auth_string.split()
    assert auth_type == 'Token'
    command = await stream.read_until(b'\n', max_bytes=120)
    command_string = command.decode('ASCII')
    cmd, arg = command_string.split()
    if cmd == 'PUT':
        stream.write(b'GRANTED PUT\n')
        while True:
            try:
                content = await stream.read_bytes(BUFFER, partial=True)
            except StreamClosedError:
                break
            await do_stuff(content)
            stream.write(b'ACK\n')
    else:
        stream.write(b'invalid command received')
    stream.close()


async def do_stuff(content):
    print(repr(content))


class BlockServer(TCPServer):
    @gen.coroutine
    def handle_stream(self, stream, address):
        print("handle stream")
        yield handler(stream)


if __name__ == '__main__':
    server = BlockServer()
    server.bind(7777)
    server.start(0)  # Forks multiple sub-processes
    IOLoop.current().start()