path: root/voctocore/lib/controlserver.py

#!/usr/bin/python3
import socket, logging, traceback
from queue import Queue
from gi.repository import GObject

from lib.commands import ControlServerCommands
from lib.tcpmulticonnection import TCPMultiConnection
from lib.response import NotifyResponse, OkResponse

class ControlServer(TCPMultiConnection):
    def __init__(self, pipeline):
        '''Initialize server and start listening.'''
        self.log = logging.getLogger('ControlServer')
        super().__init__(port=9999)

        self.command_queue = Queue()

        self.commands = ControlServerCommands(pipeline)

        GObject.idle_add(self.on_loop)

    def on_accepted(self, conn, addr):
        '''Asynchronous connection listener. Starts a handler for each connection.'''
        self.log.debug('Setting GObject io-watch on Connection')
        GObject.io_add_watch(conn, GObject.IO_IN, self.on_data, [''])
        GObject.io_add_watch(conn, GObject.IO_OUT, self.on_write)

    def on_data(self, conn, _, leftovers, *args):
        '''Asynchronous connection handler. Pushes data from socket
        into command queue linewise'''
        try:
            while True:
                try:
                    leftovers.append(conn.recv(4096).decode(errors='replace'))
                    if len(leftovers[-1]) == 0:
                        self.log.info("Socket was closed")
                        self.close_connection(conn)
                        return False
                except UnicodeDecodeError as e:
                    continue
        except BlockingIOError as e:
            pass

        data = "".join(leftovers)
        leftovers.clear()

        lines = data.split('\n')
        for line in lines[:-1]:
            self.log.debug("Got line: %r", line)

            line = line.strip()
            # TODO: move quit to on_loop
            # 'quit' = remote wants us to close the connection
            if line == 'quit':
                self.log.info("Client asked us to close the Connection")
                self.close_connection(conn)
                return False

            self.command_queue.put((line, conn))

        self.log.debug("Remaining %r", lines[-1])
        leftovers.append(lines[-1])
        return True

    def on_loop(self):
        '''Command handler. Processes commands in the command queue whenever
        nothing else is happening (registered as GObject idle callback)'''
        if self.command_queue.empty():
            return True
        line, requestor = self.command_queue.get()

        words = line.split()
        command = words[0]
        args = words[1:]

        try:
            command_function = self.commands.__class__.__dict__[command]

        except KeyError as e:
            response = "error unknown command %s\n" % command

        else:
            try:
                responseObject = command_function(self.commands, *args)

            except Exception as e:
                message = str(e) or "<no message>"
                response = "error %s\n" % message

            else:
                if isinstance(responseObject, NotifyResponse):
                    signal = "%s\n" % str(responseObject)
                    for conn, queue in self.currentConnections.items():
                        if conn == requestor:
                            continue

                        queue.put(signal)

                response = "%s\n" % str(responseObject)

        finally:
            self.currentConnections[requestor].put(response)

        return True

    def on_write(self, conn, *args):
        # TODO: on_loop() is not called as soon as there is a writable socket
        self.on_loop()

        try:
            queue = self.currentConnections[conn]
        except KeyError:
            return False

        if queue.empty():
                return True
        message = queue.get()
        try:
            conn.send(message.encode())
        except Exception as e:
            self.log.warn(e)

        return True

    def notify_all(self, msg):
        try:
            words = msg.split()
            words[-1] = self.commands.encodeSourceName(int(words[-1]))
            msg = " ".join(words) + '\n'
            for queue in self.currentConnections.values():
                queue.put(msg)
        except Exception as e:
            self.log.debug("Error during notify: %s", e)