ui: Add websocket notifications.

basicswap/contrib/websocket_server/__init__.py

@@ -0,0 +1 @@
+from .websocket_server import *

basicswap/contrib/websocket_server/thread.py

@@ -0,0 +1,38 @@
+import threading
+
+
+class ThreadWithLoggedException(threading.Thread):
+    """
+    Similar to Thread but will log exceptions to passed logger.
+
+    Args:
+        logger: Logger instance used to log any exception in child thread
+
+    Exception is also reachable via <thread>.exception from the main thread.
+    """
+
+    DIVIDER = "*"*80
+
+    def __init__(self, *args, **kwargs):
+        try:
+            self.logger = kwargs.pop("logger")
+        except KeyError:
+            raise Exception("Missing 'logger' in kwargs")
+        super().__init__(*args, **kwargs)
+        self.exception = None
+
+    def run(self):
+        try:
+            if self._target is not None:
+                self._target(*self._args, **self._kwargs)
+        except Exception as exception:
+            thread = threading.current_thread()
+            self.exception = exception
+            self.logger.exception(f"{self.DIVIDER}\nException in child thread {thread}: {exception}\n{self.DIVIDER}")
+        finally:
+            del self._target, self._args, self._kwargs
+
+
+class WebsocketServerThread(ThreadWithLoggedException):
+    """Dummy wrapper to make debug messages a bit more readable"""
+    pass

basicswap/contrib/websocket_server/websocket_server.py

@@ -0,0 +1,495 @@
+# Author: Johan Hanssen Seferidis
+# License: MIT
+
+import sys
+import struct
+import ssl
+from base64 import b64encode
+from hashlib import sha1
+import logging
+from socket import error as SocketError
+import errno
+import threading
+from socketserver import ThreadingMixIn, TCPServer, StreamRequestHandler
+
+from .thread import WebsocketServerThread
+
+logger = logging.getLogger(__name__)
+logging.basicConfig()
+
+'''
++-+-+-+-+-------+-+-------------+-------------------------------+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-------+-+-------------+-------------------------------+
+|F|R|R|R| opcode|M| Payload len |    Extended payload length    |
+|I|S|S|S|  (4)  |A|     (7)     |             (16/64)           |
+|N|V|V|V|       |S|             |   (if payload len==126/127)   |
+| |1|2|3|       |K|             |                               |
++-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
+|     Extended payload length continued, if payload len == 127  |
++ - - - - - - - - - - - - - - - +-------------------------------+
+|                     Payload Data continued ...                |
++---------------------------------------------------------------+
+'''
+
+FIN    = 0x80
+OPCODE = 0x0f
+MASKED = 0x80
+PAYLOAD_LEN = 0x7f
+PAYLOAD_LEN_EXT16 = 0x7e
+PAYLOAD_LEN_EXT64 = 0x7f
+
+OPCODE_CONTINUATION = 0x0
+OPCODE_TEXT         = 0x1
+OPCODE_BINARY       = 0x2
+OPCODE_CLOSE_CONN   = 0x8
+OPCODE_PING         = 0x9
+OPCODE_PONG         = 0xA
+
+CLOSE_STATUS_NORMAL = 1000
+DEFAULT_CLOSE_REASON = bytes('', encoding='utf-8')
+
+
+class API():
+
+    def run_forever(self, threaded=False):
+        return self._run_forever(threaded)
+
+    def new_client(self, client, server):
+        pass
+
+    def client_left(self, client, server):
+        pass
+
+    def message_received(self, client, server, message):
+        pass
+
+    def set_fn_new_client(self, fn):
+        self.new_client = fn
+
+    def set_fn_client_left(self, fn):
+        self.client_left = fn
+
+    def set_fn_message_received(self, fn):
+        self.message_received = fn
+
+    def send_message(self, client, msg):
+        self._unicast(client, msg)
+
+    def send_message_to_all(self, msg):
+        self._multicast(msg)
+
+    def deny_new_connections(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON):
+        self._deny_new_connections(status, reason)
+
+    def allow_new_connections(self):
+        self._allow_new_connections()
+
+    def shutdown_gracefully(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON):
+        self._shutdown_gracefully(status, reason)
+
+    def shutdown_abruptly(self):
+        self._shutdown_abruptly()
+
+    def disconnect_clients_gracefully(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON):
+        self._disconnect_clients_gracefully(status, reason)
+
+    def disconnect_clients_abruptly(self):
+        self._disconnect_clients_abruptly()
+
+
+class WebsocketServer(ThreadingMixIn, TCPServer, API):
+    """
+    A websocket server waiting for clients to connect.
+
+    Args:
+        port(int): Port to bind to
+        host(str): Hostname or IP to listen for connections. By default 127.0.0.1
+            is being used. To accept connections from any client, you should use
+            0.0.0.0.
+        loglevel: Logging level from logging module to use for logging. By default
+            warnings and errors are being logged.
+
+    Properties:
+        clients(list): A list of connected clients. A client is a dictionary
+            like below.
+                {
+                 'id'      : id,
+                 'handler' : handler,
+                 'address' : (addr, port)
+                }
+    """
+
+    allow_reuse_address = True
+    daemon_threads = True  # comment to keep threads alive until finished
+
+    def __init__(self, host='127.0.0.1', port=0, loglevel=logging.WARNING, key=None, cert=None):
+        logger.setLevel(loglevel)
+        TCPServer.__init__(self, (host, port), WebSocketHandler)
+        self.host = host
+        self.port = self.socket.getsockname()[1]
+        self.url = f'ws://{self.host}:{self.port}/'
+
+        self.key = key
+        self.cert = cert
+
+        self.clients = []
+        self.id_counter = 0
+        self.thread = None
+
+        self._deny_clients = False
+
+    def _run_forever(self, threaded):
+        cls_name = self.__class__.__name__
+        try:
+            logger.info("Listening on port %d for clients.." % self.port)
+            if threaded:
+                self.daemon = True
+                self.thread = WebsocketServerThread(target=super().serve_forever, daemon=True, logger=logger)
+                if sys.version_info[0] > 3 or (sys.version_info[0] == 3 and sys.version_info[1] >= 10):
+                    logger.info(f"Starting {cls_name} on thread {self.thread.name}.")
+                else:
+                    logger.info(f"Starting {cls_name} on thread {self.thread.getName()}.")
+                self.thread.start()
+            else:
+                self.thread = threading.current_thread()
+                logger.info(f"Starting {cls_name} on main thread.")
+                super().serve_forever()
+        except KeyboardInterrupt:
+            self.server_close()
+            logger.info("Server terminated.")
+        except Exception as e:
+            logger.error(str(e), exc_info=True)
+            sys.exit(1)
+
+    def _message_received_(self, handler, msg):
+        self.message_received(self.handler_to_client(handler), self, msg)
+
+    def _ping_received_(self, handler, msg):
+        handler.send_pong(msg)
+
+    def _pong_received_(self, handler, msg):
+        pass
+
+    def _new_client_(self, handler):
+        if self._deny_clients:
+            status = self._deny_clients["status"]
+            reason = self._deny_clients["reason"]
+            handler.send_close(status, reason)
+            self._terminate_client_handler(handler)
+            return
+
+        self.id_counter += 1
+        client = {
+            'id': self.id_counter,
+            'handler': handler,
+            'address': handler.client_address
+        }
+        self.clients.append(client)
+        self.new_client(client, self)
+
+    def _client_left_(self, handler):
+        client = self.handler_to_client(handler)
+        self.client_left(client, self)
+        if client in self.clients:
+            self.clients.remove(client)
+
+    def _unicast(self, receiver_client, msg):
+        receiver_client['handler'].send_message(msg)
+
+    def _multicast(self, msg):
+        for client in self.clients:
+            self._unicast(client, msg)
+
+    def handler_to_client(self, handler):
+        for client in self.clients:
+            if client['handler'] == handler:
+                return client
+
+    def _terminate_client_handler(self, handler):
+        handler.keep_alive = False
+        handler.finish()
+        handler.connection.close()
+
+    def _terminate_client_handlers(self):
+        """
+        Ensures request handler for each client is terminated correctly
+        """
+        for client in self.clients:
+            self._terminate_client_handler(client["handler"])
+
+    def _shutdown_gracefully(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON):
+        """
+        Send a CLOSE handshake to all connected clients before terminating server
+        """
+        self.keep_alive = False
+        self._disconnect_clients_gracefully(status, reason)
+        self.server_close()
+        self.shutdown()
+
+    def _shutdown_abruptly(self):
+        """
+        Terminate server without sending a CLOSE handshake
+        """
+        self.keep_alive = False
+        self._disconnect_clients_abruptly()
+        self.server_close()
+        self.shutdown()
+
+    def _disconnect_clients_gracefully(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON):
+        """
+        Terminate clients gracefully without shutting down the server
+        """
+        for client in self.clients:
+            client["handler"].send_close(status, reason)
+        self._terminate_client_handlers()
+
+    def _disconnect_clients_abruptly(self):
+        """
+        Terminate clients abruptly (no CLOSE handshake) without shutting down the server
+        """
+        self._terminate_client_handlers()
+
+    def _deny_new_connections(self, status, reason):
+        self._deny_clients = {
+            "status": status,
+            "reason": reason,
+        }
+
+    def _allow_new_connections(self):
+        self._deny_clients = False
+
+
+class WebSocketHandler(StreamRequestHandler):
+
+    def __init__(self, socket, addr, server):
+        self.server = server
+        self.timeout = 1000  # Must set a timeout or rfile.read timesout in the tests
+        assert not hasattr(self, "_send_lock"), "_send_lock already exists"
+        self._send_lock = threading.Lock()
+        if server.key and server.cert:
+            try:
+                socket = ssl.wrap_socket(socket, server_side=True, certfile=server.cert, keyfile=server.key)
+            except: # Not sure which exception it throws if the key/cert isn't found
+                logger.warning("SSL not available (are the paths {} and {} correct for the key and cert?)".format(server.key, server.cert))
+        StreamRequestHandler.__init__(self, socket, addr, server)
+
+    def setup(self):
+        StreamRequestHandler.setup(self)
+        self.keep_alive = True
+        self.handshake_done = False
+        self.valid_client = False
+
+    def handle(self):
+        while self.keep_alive:
+            if not self.handshake_done:
+                self.handshake()
+            elif self.valid_client:
+                self.read_next_message()
+
+    def read_bytes(self, num):
+        return self.rfile.read(num)
+
+    def read_next_message(self):
+        try:
+            b1, b2 = self.read_bytes(2)
+        except TimeoutError:
+            return
+        except SocketError as e:  # to be replaced with ConnectionResetError for py3
+            if e.errno == errno.ECONNRESET:
+                logger.info("Client closed connection.")
+                self.keep_alive = 0
+                return
+            b1, b2 = 0, 0
+        except ValueError as e:
+            b1, b2 = 0, 0
+
+        fin    = b1 & FIN
+        opcode = b1 & OPCODE
+        masked = b2 & MASKED
+        payload_length = b2 & PAYLOAD_LEN
+
+        if opcode == OPCODE_CLOSE_CONN:
+            logger.info("Client asked to close connection.")
+            self.keep_alive = 0
+            return
+        if not masked:
+            logger.warning("Client must always be masked.")
+            self.keep_alive = 0
+            return
+        if opcode == OPCODE_CONTINUATION:
+            logger.warning("Continuation frames are not supported.")
+            return
+        elif opcode == OPCODE_BINARY:
+            logger.warning("Binary frames are not supported.")
+            return
+        elif opcode == OPCODE_TEXT:
+            opcode_handler = self.server._message_received_
+        elif opcode == OPCODE_PING:
+            opcode_handler = self.server._ping_received_
+        elif opcode == OPCODE_PONG:
+            opcode_handler = self.server._pong_received_
+        else:
+            logger.warning("Unknown opcode %#x." % opcode)
+            self.keep_alive = 0
+            return
+
+        if payload_length == 126:
+            payload_length = struct.unpack(">H", self.rfile.read(2))[0]
+        elif payload_length == 127:
+            payload_length = struct.unpack(">Q", self.rfile.read(8))[0]
+
+        masks = self.read_bytes(4)
+        message_bytes = bytearray()
+        for message_byte in self.read_bytes(payload_length):
+            message_byte ^= masks[len(message_bytes) % 4]
+            message_bytes.append(message_byte)
+        opcode_handler(self, message_bytes.decode('utf8'))
+
+    def send_message(self, message):
+        self.send_text(message)
+
+    def send_pong(self, message):
+        self.send_text(message, OPCODE_PONG)
+
+    def send_close(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON):
+        """
+        Send CLOSE to client
+
+        Args:
+            status: Status as defined in https://datatracker.ietf.org/doc/html/rfc6455#section-7.4.1
+            reason: Text with reason of closing the connection
+        """
+        if status < CLOSE_STATUS_NORMAL or status > 1015:
+            raise Exception(f"CLOSE status must be between 1000 and 1015, got {status}")
+
+        header = bytearray()
+        payload = struct.pack('!H', status) + reason
+        payload_length = len(payload)
+        assert payload_length <= 125, "We only support short closing reasons at the moment"
+
+        # Send CLOSE with status & reason
+        header.append(FIN | OPCODE_CLOSE_CONN)
+        header.append(payload_length)
+        with self._send_lock:
+            self.request.send(header + payload)
+
+    def send_text(self, message, opcode=OPCODE_TEXT):
+        """
+        Important: Fragmented(=continuation) messages are not supported since
+        their usage cases are limited - when we don't know the payload length.
+        """
+
+        # Validate message
+        if isinstance(message, bytes):
+            message = try_decode_UTF8(message)  # this is slower but ensures we have UTF-8
+            if not message:
+                logger.warning("Can\'t send message, message is not valid UTF-8")
+                return False
+        elif not isinstance(message, str):
+            logger.warning('Can\'t send message, message has to be a string or bytes. Got %s' % type(message))
+            return False
+
+        header  = bytearray()
+        payload = encode_to_UTF8(message)
+        payload_length = len(payload)
+
+        # Normal payload
+        if payload_length <= 125:
+            header.append(FIN | opcode)
+            header.append(payload_length)
+
+        # Extended payload
+        elif payload_length >= 126 and payload_length <= 65535:
+            header.append(FIN | opcode)
+            header.append(PAYLOAD_LEN_EXT16)
+            header.extend(struct.pack(">H", payload_length))
+
+        # Huge extended payload
+        elif payload_length < 18446744073709551616:
+            header.append(FIN | opcode)
+            header.append(PAYLOAD_LEN_EXT64)
+            header.extend(struct.pack(">Q", payload_length))
+
+        else:
+            raise Exception("Message is too big. Consider breaking it into chunks.")
+            return
+
+        with self._send_lock:
+            self.request.send(header + payload)
+
+    def read_http_headers(self):
+        headers = {}
+        # first line should be HTTP GET
+        http_get = self.rfile.readline().decode().strip()
+        assert http_get.upper().startswith('GET')
+        # remaining should be headers
+        while True:
+            header = self.rfile.readline().decode().strip()
+            if not header:
+                break
+            head, value = header.split(':', 1)
+            headers[head.lower().strip()] = value.strip()
+        return headers
+
+    def handshake(self):
+        headers = self.read_http_headers()
+
+        try:
+            assert headers['upgrade'].lower() == 'websocket'
+        except AssertionError:
+            self.keep_alive = False
+            return
+
+        try:
+            key = headers['sec-websocket-key']
+        except KeyError:
+            logger.warning("Client tried to connect but was missing a key")
+            self.keep_alive = False
+            return
+
+        response = self.make_handshake_response(key)
+        with self._send_lock:
+            self.handshake_done = self.request.send(response.encode())
+        self.valid_client = True
+        self.server._new_client_(self)
+
+    @classmethod
+    def make_handshake_response(cls, key):
+        return \
+          'HTTP/1.1 101 Switching Protocols\r\n'\
+          'Upgrade: websocket\r\n'              \
+          'Connection: Upgrade\r\n'             \
+          'Sec-WebSocket-Accept: %s\r\n'        \
+          '\r\n' % cls.calculate_response_key(key)
+
+    @classmethod
+    def calculate_response_key(cls, key):
+        GUID = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
+        hash = sha1(key.encode() + GUID.encode())
+        response_key = b64encode(hash.digest()).strip()
+        return response_key.decode('ASCII')
+
+    def finish(self):
+        self.server._client_left_(self)
+
+
+def encode_to_UTF8(data):
+    try:
+        return data.encode('UTF-8')
+    except UnicodeEncodeError as e:
+        logger.error("Could not encode data to UTF-8 -- %s" % e)
+        return False
+    except Exception as e:
+        raise(e)
+        return False
+
+
+def try_decode_UTF8(data):
+    try:
+        return data.decode('utf-8')
+    except UnicodeDecodeError:
+        return False
+    except Exception as e:
+        raise(e)