astro py:docs

- Index
- Modules

### Navigation

- Astropy v5.2.1 »
- Module code »
- astropy.samp »

# Source code for astropy.samp.hub

    # Licensed under a 3-clause BSD style license - see LICENSE.rst

    import copy
    import os
    import queue
    import select
    import socket
    import threading
    import time
    import uuid
    import warnings
    import xmlrpc.client as xmlrpc
    from urllib.parse import urlunparse

    from astropy import log

    from .constants import SAMP_STATUS_OK, __profile_version__
    from .errors import SAMPHubError, SAMPProxyError, SAMPWarning
    from .lockfile_helpers import create_lock_file, read_lockfile
    from .standard_profile import ThreadingXMLRPCServer
    from .utils import ServerProxyPool, _HubAsClient, internet_on
    from .web_profile import WebProfileXMLRPCServer, web_profile_text_dialog

    __all__ = ["SAMPHubServer", "WebProfileDialog"]

    __doctest_skip__ = [".", "SAMPHubServer.*"]

    class SAMPHubServer:
        """
        SAMP Hub Server.

        Parameters
        ----------
        secret : str, optional
            The secret code to use for the SAMP lockfile. If none is is specified,
            the :func:`uuid.uuid1` function is used to generate one.

        addr : str, optional
            Listening address (or IP). This defaults to 127.0.0.1 if the internet
            is not reachable, otherwise it defaults to the host name.

        port : int, optional
            Listening XML-RPC server socket port. If left set to 0 (the default),
            the operating system will select a free port.

        lockfile : str, optional
            Custom lockfile name.

        timeout : int, optional
            Hub inactivity timeout. If ``timeout > 0`` then the Hub automatically
            stops after an inactivity period longer than ``timeout`` seconds. By
            default ``timeout`` is set to 0 (Hub never expires).

        client_timeout : int, optional
            Client inactivity timeout. If ``client_timeout > 0`` then the Hub
            automatically unregisters the clients which result inactive for a
            period longer than ``client_timeout`` seconds. By default
            ``client_timeout`` is set to 0 (clients never expire).

        mode : str, optional
            Defines the Hub running mode. If ``mode`` is ``'single'`` then the Hub
            runs using the standard ``.samp`` lock-file, having a single instance
            for user desktop session. Otherwise, if ``mode`` is ``'multiple'``,
            then the Hub runs using a non-standard lock-file, placed in
            ``.samp-1`` directory, of the form ``samp-hub-<UUID>``, where
            ``<UUID>`` is a unique UUID assigned to the hub.

        label : str, optional
            A string used to label the Hub with a human readable name. This string
            is written in the lock-file assigned to the ``hub.label`` token.

        web_profile : bool, optional
            Enables or disables the Web Profile support.

        web_profile_dialog : class, optional
            Allows a class instance to be specified using ``web_profile_dialog``
            to replace the terminal-based message with e.g. a GUI pop-up. Two
            `queue.Queue` instances will be added to the instance as attributes
            ``queue_request`` and ``queue_result``. When a request is received via
            the ``queue_request`` queue, the pop-up should be displayed, and a
            value of `True` or `False` should be added to ``queue_result``
            depending on whether the user accepted or refused the connection.

        web_port : int, optional
            The port to use for web SAMP. This should not be changed except for
            testing purposes, since web SAMP should always use port 21012.

        pool_size : int, optional
            The number of socket connections opened to communicate with the
            clients.
        """

        def __init__(
            self,
            secret=None,
            addr=None,
            port=0,
            lockfile=None,
            timeout=0,
            client_timeout=0,
            mode="single",
            label="",
            web_profile=True,
            web_profile_dialog=None,
            web_port=21012,
            pool_size=20,
        ):
            # Generate random ID for the hub
            self._id = str(uuid.uuid1())

            # General settings
            self._is_running = False
            self._customlockfilename = lockfile
            self._lockfile = None
            self._addr = addr
            self._port = port
            self._mode = mode
            self._label = label
            self._timeout = timeout
            self._client_timeout = client_timeout
            self._pool_size = pool_size

            # Web profile specific attributes
            self._web_profile = web_profile
            self._web_profile_dialog = web_profile_dialog
            self._web_port = web_port

            self._web_profile_server = None
            self._web_profile_callbacks = {}
            self._web_profile_requests_queue = None
            self._web_profile_requests_result = None
            self._web_profile_requests_semaphore = None

            self._host_name = "127.0.0.1"
            if internet_on():
                try:
                    self._host_name = socket.getfqdn()
                    socket.getaddrinfo(self._addr or self._host_name, self._port or 0)
                except OSError:
                    self._host_name = "127.0.0.1"

            # Threading stuff
            self._thread_lock = threading.Lock()
            self._thread_run = None
            self._thread_hub_timeout = None
            self._thread_client_timeout = None

            self._launched_threads = []

            # Variables for timeout testing:
            self._last_activity_time = None
            self._client_activity_time = {}

            # Hub message id counter, used to create hub msg ids
            self._hub_msg_id_counter = 0

            # Hub secret code
            self._hub_secret_code_customized = secret
            self._hub_secret = self._create_secret_code()

            # Hub public id (as SAMP client)
            self._hub_public_id = ""

            # Client ids
            # {private_key: (public_id, timestamp)}
            self._private_keys = {}

            # Metadata per client
            # {private_key: metadata}
            self._metadata = {}

            # List of subscribed clients per MType
            # {mtype: private_key list}
            self._mtype2ids = {}

            # List of subscribed MTypes per client
            # {private_key: mtype list}
            self._id2mtypes = {}

            # List of XML-RPC addresses per client
            # {public_id: (XML-RPC address, ServerProxyPool instance)}
            self._xmlrpc_endpoints = {}

            # Synchronous message id heap
            self._sync_msg_ids_heap = {}

            # Public ids counter
            self._client_id_counter = -1

        @property
        def id(self):
            """
            The unique hub ID.
            """
            return self._id

        def _register_standard_api(self, server):
            # Standard Profile only operations
            server.register_function(self._ping, "samp.hub.ping")
            server.register_function(
                self._set_xmlrpc_callback, "samp.hub.setXmlrpcCallback"
            )

            # Standard API operations
            server.register_function(self._register, "samp.hub.register")
            server.register_function(self._unregister, "samp.hub.unregister")
            server.register_function(self._declare_metadata, "samp.hub.declareMetadata")
            server.register_function(self._get_metadata, "samp.hub.getMetadata")
            server.register_function(
                self._declare_subscriptions, "samp.hub.declareSubscriptions"
            )
            server.register_function(self._get_subscriptions, "samp.hub.getSubscriptions")
            server.register_function(
                self._get_registered_clients, "samp.hub.getRegisteredClients"
            )
            server.register_function(
                self._get_subscribed_clients, "samp.hub.getSubscribedClients"
            )
            server.register_function(self._notify, "samp.hub.notify")
            server.register_function(self._notify_all, "samp.hub.notifyAll")
            server.register_function(self._call, "samp.hub.call")
            server.register_function(self._call_all, "samp.hub.callAll")
            server.register_function(self._call_and_wait, "samp.hub.callAndWait")
            server.register_function(self._reply, "samp.hub.reply")

        def _register_web_profile_api(self, server):
            # Web Profile methods like Standard Profile
            server.register_function(self._ping, "samp.webhub.ping")
            server.register_function(self._unregister, "samp.webhub.unregister")
            server.register_function(self._declare_metadata, "samp.webhub.declareMetadata")
            server.register_function(self._get_metadata, "samp.webhub.getMetadata")
            server.register_function(
                self._declare_subscriptions, "samp.webhub.declareSubscriptions"
            )
            server.register_function(
                self._get_subscriptions, "samp.webhub.getSubscriptions"
            )
            server.register_function(
                self._get_registered_clients, "samp.webhub.getRegisteredClients"
            )
            server.register_function(
                self._get_subscribed_clients, "samp.webhub.getSubscribedClients"
            )
            server.register_function(self._notify, "samp.webhub.notify")
            server.register_function(self._notify_all, "samp.webhub.notifyAll")
            server.register_function(self._call, "samp.webhub.call")
            server.register_function(self._call_all, "samp.webhub.callAll")
            server.register_function(self._call_and_wait, "samp.webhub.callAndWait")
            server.register_function(self._reply, "samp.webhub.reply")

            # Methods particularly for Web Profile
            server.register_function(self._web_profile_register, "samp.webhub.register")
            server.register_function(
                self._web_profile_allowReverseCallbacks, "samp.webhub.allowReverseCallbacks"
            )
            server.register_function(
                self._web_profile_pullCallbacks, "samp.webhub.pullCallbacks"
            )

        def _start_standard_server(self):
            self._server = ThreadingXMLRPCServer(
                (self._addr or self._host_name, self._port or 0),
                log,
                logRequests=False,
                allow_none=True,
            )
            prot = "http"

            self._port = self._server.socket.getsockname()[1]
            addr = f"{self._addr or self._host_name}:{self._port}"
            self._url = urlunparse((prot, addr, "", "", "", ""))
            self._server.register_introspection_functions()
            self._register_standard_api(self._server)

        def _start_web_profile_server(self):
            self._web_profile_requests_queue = queue.Queue(1)
            self._web_profile_requests_result = queue.Queue(1)
            self._web_profile_requests_semaphore = queue.Queue(1)

            if self._web_profile_dialog is not None:
                # TODO: Some sort of duck-typing on the web_profile_dialog object
                self._web_profile_dialog.queue_request = self._web_profile_requests_queue
                self._web_profile_dialog.queue_result = self._web_profile_requests_result

            try:
                self._web_profile_server = WebProfileXMLRPCServer(
                    ("localhost", self._web_port), log, logRequests=False, allow_none=True
                )
                self._web_port = self._web_profile_server.socket.getsockname()[1]
                self._web_profile_server.register_introspection_functions()
                self._register_web_profile_api(self._web_profile_server)
                log.info("Hub set to run with Web Profile support enabled.")
            except OSError:
                log.warning(
                    "Port {} already in use. Impossible to run the "
                    "Hub with Web Profile support.".format(self._web_port),
                    SAMPWarning,
                )
                self._web_profile = False
                # Cleanup
                self._web_profile_requests_queue = None
                self._web_profile_requests_result = None
                self._web_profile_requests_semaphore = None

        def _launch_thread(self, group=None, target=None, name=None, args=None):
            # Remove inactive threads
            remove = []
            for t in self._launched_threads:
                if not t.is_alive():
                    remove.append(t)
            for t in remove:
                self._launched_threads.remove(t)

            # Start new thread
            t = threading.Thread(group=group, target=target, name=name, args=args)
            t.start()

            # Add to list of launched threads
            self._launched_threads.append(t)

        def _join_launched_threads(self, timeout=None):
            for t in self._launched_threads:
                t.join(timeout=timeout)

        def _timeout_test_hub(self):
            if self._timeout == 0:
                return

            last = time.time()
            while self._is_running:
                time.sleep(0.05)  # keep this small to check _is_running often
                now = time.time()
                if now - last > 1.0:
                    with self._thread_lock:
                        if self._last_activity_time is not None:
                            if now - self._last_activity_time >= self._timeout:
                                warnings.warn(
                                    "Timeout expired, Hub is shutting down!", SAMPWarning
                                )
                                self.stop()
                                return
                    last = now

        def _timeout_test_client(self):
            if self._client_timeout == 0:
                return

            last = time.time()
            while self._is_running:
                time.sleep(0.05)  # keep this small to check _is_running often
                now = time.time()
                if now - last > 1.0:
                    for private_key in self._client_activity_time.keys():
                        if (
                            now - self._client_activity_time[private_key]
                            > self._client_timeout
                            and private_key != self._hub_private_key
                        ):
                            warnings.warn(
                                f"Client {private_key} timeout expired!", SAMPWarning
                            )
                            self._notify_disconnection(private_key)
                            self._unregister(private_key)
                    last = now

        def _hub_as_client_request_handler(self, method, args):
            if method == "samp.client.receiveCall":
                return self._receive_call(*args)
            elif method == "samp.client.receiveNotification":
                return self._receive_notification(*args)
            elif method == "samp.client.receiveResponse":
                return self._receive_response(*args)
            elif method == "samp.app.ping":
                return self._ping(*args)

        def _setup_hub_as_client(self):
            hub_metadata = {
                "samp.name": "Astropy SAMP Hub",
                "samp.description.text": self._label,
                "author.name": "The Astropy Collaboration",
                "samp.documentation.url": "https://docs.astropy.org/en/stable/samp",
                "samp.icon.url": self._url + "/samp/icon",
            }

            result = self._register(self._hub_secret)
            self._hub_public_id = result["samp.self-id"]
            self._hub_private_key = result["samp.private-key"]
            self._set_xmlrpc_callback(self._hub_private_key, self._url)
            self._declare_metadata(self._hub_private_key, hub_metadata)
            self._declare_subscriptions(
                self._hub_private_key, {"samp.app.ping": {}, "x-samp.query.by-meta": {}}
            )

        def start(self, wait=False):
            """
            Start the current SAMP Hub instance and create the lock file. Hub
            start-up can be blocking or non blocking depending on the ``wait``
            parameter.

            Parameters
            ----------
            wait : bool
                If `True` then the Hub process is joined with the caller, blocking
                the code flow. Usually `True` option is used to run a stand-alone
                Hub in an executable script. If `False` (default), then the Hub
                process runs in a separated thread. `False` is usually used in a
                Python shell.
            """

            if self._is_running:
                raise SAMPHubError("Hub is already running")

            if self._lockfile is not None:
                raise SAMPHubError("Hub is not running but lockfile is set")

            if self._web_profile:
                self._start_web_profile_server()

            self._start_standard_server()

            self._lockfile = create_lock_file(
                lockfilename=self._customlockfilename,
                mode=self._mode,
                hub_id=self.id,
                hub_params=self.params,
            )

            self._update_last_activity_time()
            self._setup_hub_as_client()

            self._start_threads()

            log.info("Hub started")

            if wait and self._is_running:
                self._thread_run.join()
                self._thread_run = None

        @property
        def params(self):
            """
            The hub parameters (which are written to the logfile)
            """

            params = {}

            # Keys required by standard profile

            params["samp.secret"] = self._hub_secret
            params["samp.hub.xmlrpc.url"] = self._url
            params["samp.profile.version"] = __profile_version__

            # Custom keys

            params["hub.id"] = self.id
            params["hub.label"] = self._label or f"Hub {self.id}"

            return params

        def _start_threads(self):
            self._thread_run = threading.Thread(target=self._serve_forever)
            self._thread_run.daemon = True

            if self._timeout > 0:
                self._thread_hub_timeout = threading.Thread(
                    target=self._timeout_test_hub, name="Hub timeout test"
                )
                self._thread_hub_timeout.daemon = True
            else:
                self._thread_hub_timeout = None

            if self._client_timeout > 0:
                self._thread_client_timeout = threading.Thread(
                    target=self._timeout_test_client, name="Client timeout test"
                )
                self._thread_client_timeout.daemon = True
            else:
                self._thread_client_timeout = None

            self._is_running = True
            self._thread_run.start()

            if self._thread_hub_timeout is not None:
                self._thread_hub_timeout.start()
            if self._thread_client_timeout is not None:
                self._thread_client_timeout.start()

        def _create_secret_code(self):
            if self._hub_secret_code_customized is not None:
                return self._hub_secret_code_customized
            else:
                return str(uuid.uuid1())

        def stop(self):
            """
            Stop the current SAMP Hub instance and delete the lock file.
            """

            if not self._is_running:
                return

            log.info("Hub is stopping...")

            self._notify_shutdown()

            self._is_running = False

            if self._lockfile and os.path.isfile(self._lockfile):
                lockfiledict = read_lockfile(self._lockfile)
                if lockfiledict["samp.secret"] == self._hub_secret:
                    os.remove(self._lockfile)
            self._lockfile = None

            # Reset variables
            # TODO: What happens if not all threads are stopped after timeout?
            self._join_all_threads(timeout=10.0)

            self._hub_msg_id_counter = 0
            self._hub_secret = self._create_secret_code()
            self._hub_public_id = ""
            self._metadata = {}
            self._private_keys = {}
            self._mtype2ids = {}
            self._id2mtypes = {}
            self._xmlrpc_endpoints = {}
            self._last_activity_time = None

            log.info("Hub stopped.")

        def _join_all_threads(self, timeout=None):
            # In some cases, ``stop`` may be called from some of the sub-threads,
            # so we just need to make sure that we don't try and shut down the
            # calling thread.
            current_thread = threading.current_thread()
            if self._thread_run is not current_thread:
                self._thread_run.join(timeout=timeout)
                if not self._thread_run.is_alive():
                    self._thread_run = None
            if (
                self._thread_hub_timeout is not None
                and self._thread_hub_timeout is not current_thread
            ):
                self._thread_hub_timeout.join(timeout=timeout)
                if not self._thread_hub_timeout.is_alive():
                    self._thread_hub_timeout = None
            if (
                self._thread_client_timeout is not None
                and self._thread_client_timeout is not current_thread
            ):
                self._thread_client_timeout.join(timeout=timeout)
                if not self._thread_client_timeout.is_alive():
                    self._thread_client_timeout = None

            self._join_launched_threads(timeout=timeout)

        @property
        def is_running(self):
            """Return an information concerning the Hub running status.

            Returns
            -------
            running : bool
                Is the hub running?
            """
            return self._is_running

        def _serve_forever(self):
            while self._is_running:
                try:
                    read_ready = select.select([self._server.socket], [], [], 0.01)[0]
                except OSError as exc:
                    warnings.warn(
                        f"Call to select() in SAMPHubServer failed: {exc}", SAMPWarning
                    )
                else:
                    if read_ready:
                        self._server.handle_request()

                if self._web_profile:
                    # We now check if there are any connection requests from the
                    # web profile, and if so, we initialize the pop-up.
                    if self._web_profile_dialog is None:
                        try:
                            request = self._web_profile_requests_queue.get_nowait()
                        except queue.Empty:
                            pass
                        else:
                            web_profile_text_dialog(
                                request, self._web_profile_requests_result
                            )

                    # We now check for requests over the web profile socket, and we
                    # also update the pop-up in case there are any changes.
                    try:
                        read_ready = select.select(
                            [self._web_profile_server.socket], [], [], 0.01
                        )[0]
                    except OSError as exc:
                        warnings.warn(
                            f"Call to select() in SAMPHubServer failed: {exc}", SAMPWarning
                        )
                    else:
                        if read_ready:
                            self._web_profile_server.handle_request()

            self._server.server_close()
            if self._web_profile_server is not None:
                self._web_profile_server.server_close()

        def _notify_shutdown(self):
            msubs = SAMPHubServer.get_mtype_subtypes("samp.hub.event.shutdown")
            for mtype in msubs:
                if mtype in self._mtype2ids:
                    for key in self._mtype2ids[mtype]:
                        self._notify_(
                            self._hub_private_key,
                            self._private_keys[key][0],
                            {"samp.mtype": "samp.hub.event.shutdown", "samp.params": {}},
                        )

        def _notify_register(self, private_key):
            msubs = SAMPHubServer.get_mtype_subtypes("samp.hub.event.register")
            for mtype in msubs:
                if mtype in self._mtype2ids:
                    public_id = self._private_keys[private_key][0]
                    for key in self._mtype2ids[mtype]:
                        # if key != private_key:
                        self._notify(
                            self._hub_private_key,
                            self._private_keys[key][0],
                            {
                                "samp.mtype": "samp.hub.event.register",
                                "samp.params": {"id": public_id},
                            },
                        )

        def _notify_unregister(self, private_key):
            msubs = SAMPHubServer.get_mtype_subtypes("samp.hub.event.unregister")
            for mtype in msubs:
                if mtype in self._mtype2ids:
                    public_id = self._private_keys[private_key][0]
                    for key in self._mtype2ids[mtype]:
                        if key != private_key:
                            self._notify(
                                self._hub_private_key,
                                self._private_keys[key][0],
                                {
                                    "samp.mtype": "samp.hub.event.unregister",
                                    "samp.params": {"id": public_id},
                                },
                            )

        def _notify_metadata(self, private_key):
            msubs = SAMPHubServer.get_mtype_subtypes("samp.hub.event.metadata")
            for mtype in msubs:
                if mtype in self._mtype2ids:
                    public_id = self._private_keys[private_key][0]
                    for key in self._mtype2ids[mtype]:
                        # if key != private_key:
                        self._notify(
                            self._hub_private_key,
                            self._private_keys[key][0],
                            {
                                "samp.mtype": "samp.hub.event.metadata",
                                "samp.params": {
                                    "id": public_id,
                                    "metadata": self._metadata[private_key],
                                },
                            },
                        )

        def _notify_subscriptions(self, private_key):
            msubs = SAMPHubServer.get_mtype_subtypes("samp.hub.event.subscriptions")
            for mtype in msubs:
                if mtype in self._mtype2ids:
                    public_id = self._private_keys[private_key][0]
                    for key in self._mtype2ids[mtype]:
                        self._notify(
                            self._hub_private_key,
                            self._private_keys[key][0],
                            {
                                "samp.mtype": "samp.hub.event.subscriptions",
                                "samp.params": {
                                    "id": public_id,
                                    "subscriptions": self._id2mtypes[private_key],
                                },
                            },
                        )

        def _notify_disconnection(self, private_key):
            def _xmlrpc_call_disconnect(endpoint, private_key, hub_public_id, message):
                endpoint.samp.client.receiveNotification(
                    private_key, hub_public_id, message
                )

            msubs = SAMPHubServer.get_mtype_subtypes("samp.hub.disconnect")
            public_id = self._private_keys[private_key][0]
            endpoint = self._xmlrpc_endpoints[public_id][1]

            for mtype in msubs:
                if mtype in self._mtype2ids and private_key in self._mtype2ids[mtype]:
                    log.debug(f"notify disconnection to {public_id}")
                    self._launch_thread(
                        target=_xmlrpc_call_disconnect,
                        args=(
                            endpoint,
                            private_key,
                            self._hub_public_id,
                            {
                                "samp.mtype": "samp.hub.disconnect",
                                "samp.params": {"reason": "Timeout expired!"},
                            },
                        ),
                    )

        def _ping(self):
            self._update_last_activity_time()
            log.debug("ping")
            return "1"

        def _query_by_metadata(self, key, value):
            public_id_list = []
            for private_id in self._metadata:
                if key in self._metadata[private_id]:
                    if self._metadata[private_id][key] == value:
                        public_id_list.append(self._private_keys[private_id][0])

            return public_id_list

        def _set_xmlrpc_callback(self, private_key, xmlrpc_addr):
            self._update_last_activity_time(private_key)
            if private_key in self._private_keys:
                if private_key == self._hub_private_key:
                    public_id = self._private_keys[private_key][0]
                    self._xmlrpc_endpoints[public_id] = (
                        xmlrpc_addr,
                        _HubAsClient(self._hub_as_client_request_handler),
                    )
                    return ""

                # Dictionary stored with the public id

                log.debug(f"set_xmlrpc_callback: {private_key} {xmlrpc_addr}")

                server_proxy_pool = None

                server_proxy_pool = ServerProxyPool(
                    self._pool_size, xmlrpc.ServerProxy, xmlrpc_addr, allow_none=1
                )

                public_id = self._private_keys[private_key][0]
                self._xmlrpc_endpoints[public_id] = (xmlrpc_addr, server_proxy_pool)
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

            return ""

        def _perform_standard_register(self):
            with self._thread_lock:
                private_key, public_id = self._get_new_ids()
            self._private_keys[private_key] = (public_id, time.time())
            self._update_last_activity_time(private_key)
            self._notify_register(private_key)
            log.debug(f"register: private-key = {private_key} and self-id = {public_id}")
            return {
                "samp.self-id": public_id,
                "samp.private-key": private_key,
                "samp.hub-id": self._hub_public_id,
            }

        def _register(self, secret):
            self._update_last_activity_time()
            if secret == self._hub_secret:
                return self._perform_standard_register()
            else:
                # return {"samp.self-id": "", "samp.private-key": "", "samp.hub-id": ""}
                raise SAMPProxyError(7, "Bad secret code")

        def _get_new_ids(self):
            private_key = str(uuid.uuid1())
            self._client_id_counter += 1
            public_id = "cli#hub"
            if self._client_id_counter > 0:
                public_id = f"cli#{self._client_id_counter}"

            return private_key, public_id

        def _unregister(self, private_key):
            self._update_last_activity_time()

            public_key = ""

            self._notify_unregister(private_key)

            with self._thread_lock:
                if private_key in self._private_keys:
                    public_key = self._private_keys[private_key][0]
                    del self._private_keys[private_key]
                else:
                    return ""

                if private_key in self._metadata:
                    del self._metadata[private_key]

                if private_key in self._id2mtypes:
                    del self._id2mtypes[private_key]

                for mtype in self._mtype2ids.keys():
                    if private_key in self._mtype2ids[mtype]:
                        self._mtype2ids[mtype].remove(private_key)

                if public_key in self._xmlrpc_endpoints:
                    del self._xmlrpc_endpoints[public_key]

                if private_key in self._client_activity_time:
                    del self._client_activity_time[private_key]

                if self._web_profile:
                    if private_key in self._web_profile_callbacks:
                        del self._web_profile_callbacks[private_key]
                    self._web_profile_server.remove_client(private_key)

            log.debug(f"unregister {public_key} ({private_key})")

            return ""

        def _declare_metadata(self, private_key, metadata):
            self._update_last_activity_time(private_key)
            if private_key in self._private_keys:
                log.debug(
                    "declare_metadata: private-key = {} metadata = {}".format(
                        private_key, str(metadata)
                    )
                )
                self._metadata[private_key] = metadata
                self._notify_metadata(private_key)
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")
            return ""

        def _get_metadata(self, private_key, client_id):
            self._update_last_activity_time(private_key)
            if private_key in self._private_keys:
                client_private_key = self._public_id_to_private_key(client_id)
                log.debug(
                    "get_metadata: private-key = {} client-id = {}".format(
                        private_key, client_id
                    )
                )
                if client_private_key is not None:
                    if client_private_key in self._metadata:
                        log.debug(f"--> metadata = {self._metadata[client_private_key]}")
                        return self._metadata[client_private_key]
                    else:
                        return {}
                else:
                    raise SAMPProxyError(6, "Invalid client ID")
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

        def _declare_subscriptions(self, private_key, mtypes):
            self._update_last_activity_time(private_key)

            if private_key in self._private_keys:
                log.debug(
                    "declare_subscriptions: private-key = {} mtypes = {}".format(
                        private_key, str(mtypes)
                    )
                )

                # remove subscription to previous mtypes
                if private_key in self._id2mtypes:
                    prev_mtypes = self._id2mtypes[private_key]

                    for mtype in prev_mtypes:
                        try:
                            self._mtype2ids[mtype].remove(private_key)
                        except ValueError:  # private_key is not in list
                            pass

                self._id2mtypes[private_key] = copy.deepcopy(mtypes)

                # remove duplicated MType for wildcard overwriting
                original_mtypes = copy.deepcopy(mtypes)

                for mtype in original_mtypes:
                    if mtype.endswith("*"):
                        for mtype2 in original_mtypes:
                            if mtype2.startswith(mtype[:-1]) and mtype2 != mtype:
                                if mtype2 in mtypes:
                                    del mtypes[mtype2]

                log.debug(
                    "declare_subscriptions: subscriptions accepted from {} => {}".format(
                        private_key, str(mtypes)
                    )
                )

                for mtype in mtypes:
                    if mtype in self._mtype2ids:
                        if private_key not in self._mtype2ids[mtype]:
                            self._mtype2ids[mtype].append(private_key)
                    else:
                        self._mtype2ids[mtype] = [private_key]

                self._notify_subscriptions(private_key)

            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

            return ""

        def _get_subscriptions(self, private_key, client_id):
            self._update_last_activity_time(private_key)

            if private_key in self._private_keys:
                client_private_key = self._public_id_to_private_key(client_id)
                if client_private_key is not None:
                    if client_private_key in self._id2mtypes:
                        log.debug(
                            "get_subscriptions: client-id = {} mtypes = {}".format(
                                client_id, str(self._id2mtypes[client_private_key])
                            )
                        )
                        return self._id2mtypes[client_private_key]
                    else:
                        log.debug(
                            "get_subscriptions: client-id = {} mtypes = missing".format(
                                client_id
                            )
                        )
                        return {}
                else:
                    raise SAMPProxyError(6, "Invalid client ID")
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

        def _get_registered_clients(self, private_key):
            self._update_last_activity_time(private_key)

            if private_key in self._private_keys:
                reg_clients = []
                for pkey in self._private_keys.keys():
                    if pkey != private_key:
                        reg_clients.append(self._private_keys[pkey][0])
                log.debug(
                    "get_registered_clients: private_key = {} clients = {}".format(
                        private_key, reg_clients
                    )
                )
                return reg_clients
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

        def _get_subscribed_clients(self, private_key, mtype):
            self._update_last_activity_time(private_key)

            if private_key in self._private_keys:
                sub_clients = {}

                for pkey in self._private_keys.keys():
                    if pkey != private_key and self._is_subscribed(pkey, mtype):
                        sub_clients[self._private_keys[pkey][0]] = {}

                log.debug(
                    "get_subscribed_clients: private_key = {} mtype = {} "
                    "clients = {}".format(private_key, mtype, sub_clients)
                )
                return sub_clients
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

        @staticmethod
        def get_mtype_subtypes(mtype):
            """
            Return a list containing all the possible wildcarded subtypes of MType.

            Parameters
            ----------
            mtype : str
                MType to be parsed.

            Returns
            -------
            types : list
                List of subtypes

            Examples
            --------
            >>> from astropy.samp import SAMPHubServer
            >>> SAMPHubServer.get_mtype_subtypes("samp.app.ping")
            ['samp.app.ping', 'samp.app.*', 'samp.*', '*']
            """

            subtypes = []

            msubs = mtype.split(".")
            indexes = list(range(len(msubs)))
            indexes.reverse()
            indexes.append(-1)

            for i in indexes:
                tmp_mtype = ".".join(msubs[: i + 1])
                if tmp_mtype != mtype:
                    if tmp_mtype != "":
                        tmp_mtype = tmp_mtype + ".*"
                    else:
                        tmp_mtype = "*"
                subtypes.append(tmp_mtype)

            return subtypes

        def _is_subscribed(self, private_key, mtype):
            subscribed = False

            msubs = SAMPHubServer.get_mtype_subtypes(mtype)

            for msub in msubs:
                if msub in self._mtype2ids:
                    if private_key in self._mtype2ids[msub]:
                        subscribed = True

            return subscribed

        def _notify(self, private_key, recipient_id, message):
            self._update_last_activity_time(private_key)

            if private_key in self._private_keys:
                if not (
                    self._is_subscribed(
                        self._public_id_to_private_key(recipient_id), message["samp.mtype"]
                    )
                ):
                    raise SAMPProxyError(
                        2,
                        "Client {} not subscribed to MType {}".format(
                            recipient_id, message["samp.mtype"]
                        ),
                    )

                self._launch_thread(
                    target=self._notify_, args=(private_key, recipient_id, message)
                )
                return {}
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

        def _notify_(self, sender_private_key, recipient_public_id, message):
            if sender_private_key not in self._private_keys:
                return

            sender_public_id = self._private_keys[sender_private_key][0]

            try:
                log.debug(
                    "notify {} from {} to {}".format(
                        message["samp.mtype"], sender_public_id, recipient_public_id
                    )
                )

                recipient_private_key = self._public_id_to_private_key(recipient_public_id)
                arg_params = (sender_public_id, message)
                samp_method_name = "receiveNotification"

                self._retry_method(
                    recipient_private_key, recipient_public_id, samp_method_name, arg_params
                )

            except Exception as exc:
                warnings.warn(
                    "{} notification from client {} to client {} failed [{}]".format(
                        message["samp.mtype"], sender_public_id, recipient_public_id, exc
                    ),
                    SAMPWarning,
                )

        def _notify_all(self, private_key, message):
            self._update_last_activity_time(private_key)

            if private_key in self._private_keys:
                if "samp.mtype" not in message:
                    raise SAMPProxyError(3, "samp.mtype keyword is missing")
                recipient_ids = self._notify_all_(private_key, message)
                return recipient_ids
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

        def _notify_all_(self, sender_private_key, message):
            recipient_ids = []
            msubs = SAMPHubServer.get_mtype_subtypes(message["samp.mtype"])

            for mtype in msubs:
                if mtype in self._mtype2ids:
                    for key in self._mtype2ids[mtype]:
                        if key != sender_private_key:
                            _recipient_id = self._private_keys[key][0]
                            recipient_ids.append(_recipient_id)
                            self._launch_thread(
                                target=self._notify,
                                args=(sender_private_key, _recipient_id, message),
                            )

            return recipient_ids

        def _call(self, private_key, recipient_id, msg_tag, message):
            self._update_last_activity_time(private_key)

            if private_key in self._private_keys:
                if not (
                    self._is_subscribed(
                        self._public_id_to_private_key(recipient_id), message["samp.mtype"]
                    )
                ):
                    raise SAMPProxyError(
                        2,
                        "Client {} not subscribed to MType {}".format(
                            recipient_id, message["samp.mtype"]
                        ),
                    )
                public_id = self._private_keys[private_key][0]
                msg_id = self._get_new_hub_msg_id(public_id, msg_tag)
                self._launch_thread(
                    target=self._call_,
                    args=(private_key, public_id, recipient_id, msg_id, message),
                )
                return msg_id
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

        def _call_(
            self, sender_private_key, sender_public_id, recipient_public_id, msg_id, message
        ):
            if sender_private_key not in self._private_keys:
                return

            try:
                log.debug(
                    "call {} from {} to {} ({})".format(
                        msg_id.split(";;")[0],
                        sender_public_id,
                        recipient_public_id,
                        message["samp.mtype"],
                    )
                )

                recipient_private_key = self._public_id_to_private_key(recipient_public_id)
                arg_params = (sender_public_id, msg_id, message)
                samp_methodName = "receiveCall"

                self._retry_method(
                    recipient_private_key, recipient_public_id, samp_methodName, arg_params
                )

            except Exception as exc:
                warnings.warn(
                    "{} call {} from client {} to client {} failed [{},{}]".format(
                        message["samp.mtype"],
                        msg_id.split(";;")[0],
                        sender_public_id,
                        recipient_public_id,
                        type(exc),
                        exc,
                    ),
                    SAMPWarning,
                )

        def _call_all(self, private_key, msg_tag, message):
            self._update_last_activity_time(private_key)

            if private_key in self._private_keys:
                if "samp.mtype" not in message:
                    raise SAMPProxyError(
                        3,
                        "samp.mtype keyword is missing in message tagged as {}".format(
                            msg_tag
                        ),
                    )

                public_id = self._private_keys[private_key][0]
                msg_id = self._call_all_(private_key, public_id, msg_tag, message)
                return msg_id
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

        def _call_all_(self, sender_private_key, sender_public_id, msg_tag, message):
            msg_id = {}
            msubs = SAMPHubServer.get_mtype_subtypes(message["samp.mtype"])

            for mtype in msubs:
                if mtype in self._mtype2ids:
                    for key in self._mtype2ids[mtype]:
                        if key != sender_private_key:
                            _msg_id = self._get_new_hub_msg_id(sender_public_id, msg_tag)
                            receiver_public_id = self._private_keys[key][0]
                            msg_id[receiver_public_id] = _msg_id
                            self._launch_thread(
                                target=self._call_,
                                args=(
                                    sender_private_key,
                                    sender_public_id,
                                    receiver_public_id,
                                    _msg_id,
                                    message,
                                ),
                            )
            return msg_id

        def _call_and_wait(self, private_key, recipient_id, message, timeout):
            self._update_last_activity_time(private_key)

            if private_key in self._private_keys:
                timeout = int(timeout)

                now = time.time()
                response = {}

                msg_id = self._call(private_key, recipient_id, "samp::sync::call", message)
                self._sync_msg_ids_heap[msg_id] = None

                while self._is_running:
                    if 0 < timeout <= time.time() - now:
                        del self._sync_msg_ids_heap[msg_id]
                        raise SAMPProxyError(1, "Timeout expired!")

                    if self._sync_msg_ids_heap[msg_id] is not None:
                        response = copy.deepcopy(self._sync_msg_ids_heap[msg_id])
                        del self._sync_msg_ids_heap[msg_id]
                        break
                    time.sleep(0.01)

                return response
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

        def _reply(self, private_key, msg_id, response):
            """
            The main method that gets called for replying. This starts up an
            asynchronous reply thread and returns.
            """
            self._update_last_activity_time(private_key)
            if private_key in self._private_keys:
                self._launch_thread(
                    target=self._reply_, args=(private_key, msg_id, response)
                )
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

            return {}

        def _reply_(self, responder_private_key, msg_id, response):
            if responder_private_key not in self._private_keys or not msg_id:
                return

            responder_public_id = self._private_keys[responder_private_key][0]
            counter, hub_public_id, recipient_public_id, recipient_msg_tag = msg_id.split(
                ";;", 3
            )

            try:
                log.debug(
                    "reply {} from {} to {}".format(
                        counter, responder_public_id, recipient_public_id
                    )
                )

                if recipient_msg_tag == "samp::sync::call":
                    if msg_id in self._sync_msg_ids_heap.keys():
                        self._sync_msg_ids_heap[msg_id] = response

                else:
                    recipient_private_key = self._public_id_to_private_key(
                        recipient_public_id
                    )
                    arg_params = (responder_public_id, recipient_msg_tag, response)
                    samp_method_name = "receiveResponse"

                    self._retry_method(
                        recipient_private_key,
                        recipient_public_id,
                        samp_method_name,
                        arg_params,
                    )

            except Exception as exc:
                warnings.warn(
                    "{} reply from client {} to client {} failed [{}]".format(
                        recipient_msg_tag, responder_public_id, recipient_public_id, exc
                    ),
                    SAMPWarning,
                )

        def _retry_method(
            self, recipient_private_key, recipient_public_id, samp_method_name, arg_params
        ):
            """
            This method is used to retry a SAMP call several times.

            Parameters
            ----------
            recipient_private_key
                The private key of the receiver of the call
            recipient_public_key
                The public key of the receiver of the call
            samp_method_name : str
                The name of the SAMP method to call
            arg_params : tuple
                Any additional arguments to be passed to the SAMP method
            """

            if recipient_private_key is None:
                raise SAMPHubError("Invalid client ID")

            from . import conf

            for attempt in range(conf.n_retries):
                if not self._is_running:
                    time.sleep(0.01)
                    continue

                try:
                    if (
                        self._web_profile
                        and recipient_private_key in self._web_profile_callbacks
                    ):
                        # Web Profile
                        callback = {
                            "samp.methodName": samp_method_name,
                            "samp.params": arg_params,
                        }
                        self._web_profile_callbacks[recipient_private_key].put(callback)

                    else:
                        # Standard Profile
                        hub = self._xmlrpc_endpoints[recipient_public_id][1]
                        getattr(hub.samp.client, samp_method_name)(
                            recipient_private_key, *arg_params
                        )

                except xmlrpc.Fault as exc:
                    log.debug(
                        "{} XML-RPC endpoint error (attempt {}): {}".format(
                            recipient_public_id, attempt + 1, exc.faultString
                        )
                    )
                    time.sleep(0.01)
                else:
                    return

            # If we are here, then the above attempts failed
            error_message = (
                samp_method_name + " failed after " + str(conf.n_retries) + " attempts"
            )
            raise SAMPHubError(error_message)

        def _public_id_to_private_key(self, public_id):
            for private_key in self._private_keys.keys():
                if self._private_keys[private_key][0] == public_id:
                    return private_key
            return None

        def _get_new_hub_msg_id(self, sender_public_id, sender_msg_id):
            with self._thread_lock:
                self._hub_msg_id_counter += 1
            return "msg#{};;{};;{};;{}".format(
                self._hub_msg_id_counter,
                self._hub_public_id,
                sender_public_id,
                sender_msg_id,
            )

        def _update_last_activity_time(self, private_key=None):
            with self._thread_lock:
                self._last_activity_time = time.time()
                if private_key is not None:
                    self._client_activity_time[private_key] = time.time()

        def _receive_notification(self, private_key, sender_id, message):
            return ""

        def _receive_call(self, private_key, sender_id, msg_id, message):
            if private_key == self._hub_private_key:
                if "samp.mtype" in message and message["samp.mtype"] == "samp.app.ping":
                    self._reply(
                        self._hub_private_key,
                        msg_id,
                        {"samp.status": SAMP_STATUS_OK, "samp.result": {}},
                    )

                elif "samp.mtype" in message and (
                    message["samp.mtype"] == "x-samp.query.by-meta"
                    or message["samp.mtype"] == "samp.query.by-meta"
                ):
                    ids_list = self._query_by_metadata(
                        message["samp.params"]["key"], message["samp.params"]["value"]
                    )
                    self._reply(
                        self._hub_private_key,
                        msg_id,
                        {"samp.status": SAMP_STATUS_OK, "samp.result": {"ids": ids_list}},
                    )

                return ""
            else:
                return ""

        def _receive_response(self, private_key, responder_id, msg_tag, response):
            return ""

        def _web_profile_register(
            self, identity_info, client_address=("unknown", 0), origin="unknown"
        ):
            self._update_last_activity_time()

            if not client_address[0] in ["localhost", "127.0.0.1"]:
                raise SAMPProxyError(403, "Request of registration rejected by the Hub.")

            if not origin:
                origin = "unknown"

            if isinstance(identity_info, dict):
                # an old version of the protocol provided just a string with the app name
                if "samp.name" not in identity_info:
                    raise SAMPProxyError(
                        403,
                        "Request of registration rejected "
                        "by the Hub (application name not "
                        "provided).",
                    )

            # Red semaphore for the other threads
            self._web_profile_requests_semaphore.put("wait")
            # Set the request to be displayed for the current thread
            self._web_profile_requests_queue.put((identity_info, client_address, origin))
            # Get the popup dialogue response
            response = self._web_profile_requests_result.get()
            # OK, semaphore green
            self._web_profile_requests_semaphore.get()

            if response:
                register_map = self._perform_standard_register()
                translator_url = "http://localhost:{}/translator/{}?ref=".format(
                    self._web_port, register_map["samp.private-key"]
                )
                register_map["samp.url-translator"] = translator_url
                self._web_profile_server.add_client(register_map["samp.private-key"])
                return register_map
            else:
                raise SAMPProxyError(403, "Request of registration rejected by the user.")

        def _web_profile_allowReverseCallbacks(self, private_key, allow):
            self._update_last_activity_time()
            if private_key in self._private_keys:
                if allow == "0":
                    if private_key in self._web_profile_callbacks:
                        del self._web_profile_callbacks[private_key]
                else:
                    self._web_profile_callbacks[private_key] = queue.Queue()
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")
            return ""

        def _web_profile_pullCallbacks(self, private_key, timeout_secs):
            self._update_last_activity_time()
            if private_key in self._private_keys:
                callback = []
                callback_queue = self._web_profile_callbacks[private_key]
                try:
                    while self._is_running:
                        item_queued = callback_queue.get_nowait()
                        callback.append(item_queued)
                except queue.Empty:
                    pass
                return callback
            else:
                raise SAMPProxyError(5, f"Private-key {private_key} expired or invalid.")

    class WebProfileDialog:
        """
        A base class to make writing Web Profile GUI consent dialogs
        easier.

        The concrete class must:

            1) Poll ``handle_queue`` periodically, using the timer services
               of the GUI's event loop.  This function will call
               ``self.show_dialog`` when a request requires authorization.
               ``self.show_dialog`` will be given the arguments:

                  - ``samp_name``: The name of the application making the request.

                  - ``details``: A dictionary of details about the client
                    making the request.

                  - ``client``: A hostname, port pair containing the client
                    address.

                  - ``origin``: A string containing the origin of the
                    request.

            2) Call ``consent`` or ``reject`` based on the user's response to
               the dialog.
        """

        def handle_queue(self):
            try:
                request = self.queue_request.get_nowait()
            except queue.Empty:  # queue is set but empty
                pass
            except AttributeError:  # queue has not been set yet
                pass
            else:
                if isinstance(request[0], str):  # To support the old protocol version
                    samp_name = request[0]
                else:
                    samp_name = request[0]["samp.name"]

                self.show_dialog(samp_name, request[0], request[1], request[2])

        def consent(self):
            self.queue_result.put(True)

        def reject(self):
            self.queue_result.put(False)