#!/usr/bin/env python # -*- coding: utf-8 -*- # """ socket_protocol (Socket Protocol) ================================= **Author:** * Dirk Alders **Description:** This Module supports point to point communication for client-server issues. **Submodules:** * :class:`socket_protocol.data_storage` * :class:`socket_protocol.pure_json_protocol` * :class:`socket_protocol.struct_json_protocol` **Unittest:** See also the :download:`unittest ` documentation. **Module Documentation:** """ __DEPENDENCIES__ = ['stringtools'] import stringtools import binascii import hashlib import json import logging import os import struct import sys import time try: from config import APP_NAME as ROOT_LOGGER_NAME except ImportError: ROOT_LOGGER_NAME = 'root' logger = logging.getLogger(ROOT_LOGGER_NAME).getChild(__name__) __DESCRIPTION__ = """The Module {\\tt %s} is designed for point to point communication for client-server issues. For more Information read the sphinx documentation.""" % __name__.replace('_', '\_') """The Module Description""" __INTERPRETER__ = (2, 3) """The Tested Interpreter-Versions""" SID_AUTH_REQUEST = 0 """SID for authentification request""" SID_AUTH_RESPONSE = 1 """SID for authentification response""" DID_AUTH_SEED = 0 """DID for authentification (seed)""" DID_AUTH_KEY = 1 """DID for authentification (key)""" SID_CHANNEL_NAME_REQUEST = 8 """SID for channel name exchange request """ SID_CHANNEL_NAME_RESPONSE = 9 """SID for channel name exchange response""" DID_CHANNEL_NAME = 0 """DID for channel name """ SID_READ_REQUEST = 10 """SID for a read data request""" SID_READ_RESPONSE = 11 """SID for read data response""" SID_WRITE_REQUEST = 20 """SID for a write data request""" SID_WRITE_RESPONSE = 21 """SID for a write data response""" SID_EXECUTE_REQUEST = 30 """SID for a execute request""" SID_EXECUTE_RESPONSE = 31 """SID for a execute response""" STATUS_OKAY = 0 """Status for 'okay'""" STATUS_BUFFERING_UNHANDLED_REQUEST = 1 """Status for 'unhandled request'""" STATUS_CALLBACK_ERROR = 2 """Status for 'callback errors'""" STATUS_AUTH_REQUIRED = 3 """Status for 'authentification is required'""" STATUS_SERVICE_OR_DATA_UNKNOWN = 4 """Status for 'service or data unknown'""" STATUS_CHECKSUM_ERROR = 5 """Status for 'checksum error'""" STATUS_OPERATION_NOT_PERMITTED = 6 """Status for 'operation not permitted'""" AUTH_STATE_UNTRUSTED_CONNECTION = 0 """Authentification Status for an 'Untrusted Connection'""" AUTH_STATE_SEED_REQUESTED = 1 """Authentification Status for 'Seed was requested'""" AUTH_STATE_SEED_TRANSFERRED = 2 """Authentification Status for 'Seed has been sent'""" AUTH_STATE_KEY_TRANSFERRED = 3 """Authentification Status for 'Key has been sent'""" AUTH_STATE_TRUSTED_CONNECTION = 4 """Authentification Status for a 'Trusted Connection'""" AUTH_STATE__NAMES = {AUTH_STATE_UNTRUSTED_CONNECTION: 'Untrusted Connection', AUTH_STATE_SEED_REQUESTED: 'Seed was requested', AUTH_STATE_SEED_TRANSFERRED: 'Seed has been sent', AUTH_STATE_KEY_TRANSFERRED: 'Key has been sent', AUTH_STATE_TRUSTED_CONNECTION: 'Trusted Connection'} """Authentification Status names for previous defined authentification states""" class RequestSidExistsError(Exception): pass class ResponseSidExistsError(Exception): pass class _callback_storage(dict): DEFAULT_CHANNEL_NAME = 'all_others' def __init__(self, channel_name, log_prefix): self.init_channel_name(channel_name) self.__log_prefix__ = log_prefix dict.__init__(self) def init_channel_name(self, channel_name): if channel_name is None: self.logger = logging.getLogger(ROOT_LOGGER_NAME).getChild(__name__ + '.' + self.DEFAULT_CHANNEL_NAME) else: self.logger = logging.getLogger(ROOT_LOGGER_NAME).getChild(__name__ + '.' + channel_name) def get(self, service_id, data_id): if dict.get(self, service_id, {}).get(data_id, None) is not None: return self[service_id][data_id] elif dict.get(self, service_id, {}).get(None, None) is not None: return self[service_id][None] elif dict.get(self, None, {}).get(data_id, None) is not None: return self[None][data_id] elif dict.get(self, None, {}).get(None, None) is not None: return self[None][None] else: return (None, None, None) def add(self, service_id, data_id, callback, *args, **kwargs): cb_data = self.get(service_id, data_id) if dict.get(self, service_id, {}).get(data_id, None) is not None: if callback is None: self.logger.warning("%s Deleting existing callback %s for service_id (%s) and data_id (%s)!", self.__log_prefix__(), repr(cb_data[0].__name__), repr(service_id), repr(data_id)) del(self[service_id][data_id]) return else: self.logger.warning("%s Overwriting existing callback %s for service_id (%s) and data_id (%s) to %s!", self.__log_prefix__(), repr(cb_data[0].__name__), repr(service_id), repr(data_id), repr(callback.__name__)) else: self.logger.debug("%s Adding callback %s for SID=%s and DID=%s", self.__log_prefix__(), repr(callback.__name__), repr(service_id), repr(data_id)) if service_id not in self: self[service_id] = {} self[service_id][data_id] = (callback, args, kwargs) class data_storage(dict): """ This is a storage object for socket_protocol messages. :param status: The message status. :type status: int :param service_id: The Service-ID. :type service_id: int :param data_id: The Data-ID. :type data_id: int :param data: The transfered data. :type data: any """ KEY_STATUS = 'status' KEY_SERVICE_ID = 'service_id' KEY_DATA_ID = 'data_id' KEY_DATA = 'data' ALL_KEYS = [KEY_DATA, KEY_DATA_ID, KEY_SERVICE_ID, KEY_STATUS] def __init__(self, *args, **kwargs): dict.__init__(self, *args, **kwargs) for key in self.ALL_KEYS: if key not in self: self[key] = None def get_status(self, default=None): """ This Method returns the message status. :param default: The default value, if no data is available. """ return self.get(self.KEY_STATUS, default) def get_service_id(self, default=None): """ This Method returns the message Service-ID. :param default: The default value, if no data is available. """ return self.get(self.KEY_SERVICE_ID, default) def get_data_id(self, default=None): """ This Method returns the message Data-ID. :param default: The default value, if no data is available. """ return self.get(self.KEY_DATA_ID, default) def get_data(self, default=None): """ This Method returns the message data. :param default: The default value, if no data is available. """ return self.get(self.KEY_DATA, default) class pure_json_protocol(object): """ This `class` supports to transfer a message and it's data. :param comm_instance: A communication instance. :type comm_instance: instance :param secret: An optinal secret (e.g. created by ``binascii.hexlify(os.urandom(24))``). :type secret: str :param auto_auth: An optional parameter to enable (True) automatic authentification, otherwise you need to do it manually, if needed. :type auto_auth: bool :param channel_name: An optional parameter to set a channel name for logging of the communication. :type channel_name: str .. hint:: * The Service-ID is designed to identify the type of the communication (e.g. :const:`READ_REQUEST`, :const:`WRITE_REQUEST`, :const:`READ_RESPONSE`, :const:`WRITE_RESPONSE`, ...) * The Data-ID is designed to identify the requests / responses using the same Service_ID. .. note:: The :class:`comm_instance` needs to have at least the following interface: * A Method :func:`comm_instance.init_channel_name` to set the channel name. * A Constant :const:`comm_instance.IS_CLIENT` to identify that the :class:`comm_instance` is a client (True) or a server (False). * A Method :func:`comm_instance.is_connected` to identify if the instance is connected (True) or not (False). * A Method :func:`comm_instance.reconnect` to initiate a reconnect. * A Method :func:`comm_instance.register_callback` to register a data available callback. * A Method :func:`comm_instance.register_connect_callback` to register a connect callback. * A Method :func:`comm_instance.register_disconnect_callback` to register a disconnect callback. * A Method :func:`comm_instance.send` to send data via the :class:`comm_instance`. .. note:: The parameter :const:`auto_auth` is only relevant, if a secret is given and the :class:`comm_instance` is a client. The authentification is initiated directly after the connection is established. .. note:: The :const:`channel_name`-exchange will be initiated by the client directly after the the connection is established. * If a channel_name is given at both communication sides and they are different, the client name is taken over and the server will log a warning message. """ DEFAULT_CHANNEL_NAME = 'all_others' def __init__(self, comm_instance, secret=None, auto_auth=False, channel_name=None): self.__comm_inst__ = comm_instance self.__secret__ = secret self.__auto_auth__ = auto_auth # self.__auth_whitelist__ = {} self.__sid_response_dict__ = {} self.__sid_name_dict__ = {} self.__did_name_dict__ = {} # self.__status_name_dict = {} self.add_status(STATUS_OKAY, 'okay') self.add_status(STATUS_BUFFERING_UNHANDLED_REQUEST, 'no callback for service, data buffered.') self.add_status(STATUS_CALLBACK_ERROR, 'callback error.') self.add_status(STATUS_AUTH_REQUIRED, 'authentification required') self.add_status(STATUS_SERVICE_OR_DATA_UNKNOWN, 'service or data unknown') self.add_status(STATUS_CHECKSUM_ERROR, 'checksum error') self.add_status(STATUS_OPERATION_NOT_PERMITTED, 'operation not permitted') # self.__callbacks__ = _callback_storage(channel_name, self.__log_prefix__) self.__init_channel_name__(channel_name) # self.__clean_receive_buffer__() self.add_service(SID_AUTH_REQUEST, SID_AUTH_RESPONSE, 'authentification request', 'authentification response') self.add_data((SID_AUTH_REQUEST, SID_AUTH_RESPONSE), DID_AUTH_SEED, 'seed') self.add_data(SID_AUTH_REQUEST, DID_AUTH_KEY, 'key') self.add_data(SID_AUTH_RESPONSE, DID_AUTH_KEY, 'key') self.add_msg_to_auth_whitelist_(SID_AUTH_REQUEST, DID_AUTH_SEED) self.add_msg_to_auth_whitelist_(SID_AUTH_RESPONSE, DID_AUTH_SEED) self.add_msg_to_auth_whitelist_(SID_AUTH_REQUEST, DID_AUTH_KEY) self.add_msg_to_auth_whitelist_(SID_AUTH_RESPONSE, DID_AUTH_KEY) self.__callbacks__.add(SID_AUTH_REQUEST, DID_AUTH_SEED, self.__authentificate_create_seed__) self.__callbacks__.add(SID_AUTH_RESPONSE, DID_AUTH_SEED, self.__authentificate_create_key__) self.__callbacks__.add(SID_AUTH_REQUEST, DID_AUTH_KEY, self.__authentificate_check_key__) self.__callbacks__.add(SID_AUTH_RESPONSE, DID_AUTH_KEY, self.__authentificate_process_feedback__) self.__authentification_state_reset__() self.add_service(SID_CHANNEL_NAME_REQUEST, SID_CHANNEL_NAME_RESPONSE, 'channel name request', 'channel name response') self.add_data((SID_CHANNEL_NAME_REQUEST, SID_CHANNEL_NAME_RESPONSE), DID_CHANNEL_NAME, 'name') self.add_msg_to_auth_whitelist_(SID_CHANNEL_NAME_REQUEST, DID_CHANNEL_NAME) self.add_msg_to_auth_whitelist_(SID_CHANNEL_NAME_RESPONSE, DID_CHANNEL_NAME) self.__callbacks__.add(SID_CHANNEL_NAME_REQUEST, DID_CHANNEL_NAME, self.__channel_name_request__) self.__callbacks__.add(SID_CHANNEL_NAME_RESPONSE, DID_CHANNEL_NAME, self.__channel_name_response__) self.add_service(SID_READ_REQUEST, SID_READ_RESPONSE, 'read data request', 'read data response') self.add_service(SID_WRITE_REQUEST, SID_WRITE_RESPONSE, 'write data request', 'write data response') self.add_service(SID_EXECUTE_REQUEST, SID_EXECUTE_RESPONSE, 'execute request', 'execute response') self.__seed__ = None self.__comm_inst__.register_callback(self.__data_available_callback__) self.__comm_inst__.register_connect_callback(self.__connection_established__) self.__comm_inst__.register_disconnect_callback(self.__authentification_state_reset__) logger.info('%s Initialisation finished.', self.__log_prefix__()) def __analyse_frame__(self, frame): if sys.version_info >= (3, 0): return data_storage(json.loads(frame[:-4].decode('utf-8'))) else: return data_storage(json.loads(frame[:-4])) def __authentificate_check_key__(self, msg): key = msg.get_data() if key == self.__authentificate_salt_and_hash__(self.__seed__): self.__authentification_state__ = AUTH_STATE_TRUSTED_CONNECTION return STATUS_OKAY, True else: self.__authentification_state__ = AUTH_STATE_UNTRUSTED_CONNECTION return STATUS_OKAY, False def __authentificate_create_key__(self, msg): self.__authentification_state__ = AUTH_STATE_KEY_TRANSFERRED seed = msg.get_data() key = self.__authentificate_salt_and_hash__(seed) self.send(SID_AUTH_REQUEST, DID_AUTH_KEY, key) def __authentificate_create_seed__(self, msg): self.__authentification_state__ = AUTH_STATE_SEED_TRANSFERRED if sys.version_info >= (3, 0): self.__seed__ = binascii.hexlify(os.urandom(32)).decode('utf-8') else: self.__seed__ = binascii.hexlify(os.urandom(32)) return STATUS_OKAY, self.__seed__ def __authentificate_process_feedback__(self, msg): feedback = msg.get_data() if feedback: self.__authentification_state__ = AUTH_STATE_TRUSTED_CONNECTION self.logger.info("%s Got positive authentification feedback", self.__log_prefix__()) else: self.__authentification_state__ = AUTH_STATE_UNTRUSTED_CONNECTION self.logger.warning("%s Got negative authentification feedback", self.__log_prefix__()) return STATUS_OKAY, None def __authentificate_salt_and_hash__(self, seed): if sys.version_info >= (3, 0): return hashlib.sha512(bytes(seed, 'utf-8') + self.__secret__).hexdigest() else: return hashlib.sha512(seed.encode('utf-8') + self.__secret__.encode('utf-8')).hexdigest() def __authentification_state_reset__(self): self.logger.info("%s Resetting authentification state to AUTH_STATE_UNTRUSTED_CONNECTION", self.__log_prefix__()) self.__authentification_state__ = AUTH_STATE_UNTRUSTED_CONNECTION def __authentification_required__(self, service_id, data_id): return data_id not in self.__auth_whitelist__.get(service_id, []) def __buffer_received_data__(self, msg): if not msg.get_service_id() in self.__msg_buffer__: self.__msg_buffer__[msg.get_service_id()] = {} if not msg.get_data_id() in self.__msg_buffer__[msg.get_service_id()]: self.__msg_buffer__[msg.get_service_id()][msg.get_data_id()] = [] self.__msg_buffer__[msg.get_service_id()][msg.get_data_id()].append(msg) self.logger.debug("%s Message data is stored in buffer and is now ready to be retrieved by receive method", self.__log_prefix__()) def __build_frame__(self, service_id, data_id, data, status=STATUS_OKAY): data_frame = json.dumps(self.__mk_msg__(status, service_id, data_id, data)) if sys.version_info >= (3, 0): data_frame = bytes(data_frame, 'utf-8') checksum = self.__calc_chksum__(data_frame) return data_frame + checksum def __calc_chksum__(self, raw_data): return struct.pack('>I', binascii.crc32(raw_data) & 0xffffffff) @property def __channel_name__(self): cn = self.logger.name.split('.')[-1] if cn != self.DEFAULT_CHANNEL_NAME: return cn def __channel_name_response__(self, msg): data = msg.get_data() if self.__channel_name__ is None and data is not None: self.__init_channel_name__(data) self.logger.info('%s channel name is now %s', self.__log_prefix__(), repr(self.__channel_name__)) return STATUS_OKAY, None def __channel_name_request__(self, msg): data = msg.get_data() if data is None: return STATUS_OKAY, self.__channel_name__ else: prev_channel_name = self.__channel_name__ self.__init_channel_name__(data) if prev_channel_name is not None and prev_channel_name != data: self.logger.warning('%s overwriting user defined channel name from %s to %s', self.__log_prefix__(), repr(prev_channel_name), repr(data)) elif prev_channel_name is None: self.logger.info('%s channel name is now %s', self.__log_prefix__(), repr(self.__channel_name__)) return STATUS_OKAY, None def __check_frame_checksum__(self, frame): return self.__calc_chksum__(frame[:-4]) == frame[-4:] def __clean_receive_buffer__(self): self.logger.debug("%s Cleaning up receive-buffer", self.__log_prefix__()) self.__msg_buffer__ = {} def __connection_established__(self): self.__clean_receive_buffer__() if self.__comm_inst__.IS_CLIENT: self.send(SID_CHANNEL_NAME_REQUEST, 0, self.__channel_name__) if self.__auto_auth__ and self.__comm_inst__.IS_CLIENT and self.__secret__ is not None: self.authentificate() def __data_available_callback__(self, comm_inst): frame = comm_inst.receive() msg = self.__analyse_frame__(frame) if not self.__check_frame_checksum__(frame): # Wrong Checksum self.logger.warning("%s RX <- Received message has a wrong checksum. Message will be ignored.", self.__log_prefix__()) return # No response needed elif not self.check_authentification_state() and self.__authentification_required__(msg.get_service_id(), msg.get_data_id()): # Authentification required if msg.get_service_id() in self.__sid_response_dict__.keys(): self.logger.warning("%s RX <- Authentification is required. Just sending negative response.", self.__log_prefix__()) status = STATUS_AUTH_REQUIRED data = None else: self.logger.warning("%s RX <- Authentification is required. Message will be ignored.", self.__log_prefix__()) return # No response needed else: # Valid message self.logger.info( '%s RX <- %s, %s, data: "%s"', self.__log_prefix__(), self.__get_message_name__(msg.get_service_id(), msg.get_data_id()), self.__get_status_name__(msg.get_status()), repr(msg.get_data()) ) if msg.get_status() not in [STATUS_OKAY]: self.logger.warning("%s RX <- Message has a peculiar status: %s", self.__log_prefix__(), self.__get_status_name__(msg.get_status())) callback, args, kwargs = self.__callbacks__.get(msg.get_service_id(), msg.get_data_id()) if msg.get_service_id() in self.__sid_response_dict__.keys(): # # REQUEST RECEIVED # if callback is None: self.logger.warning("%s RX <- Message with no registered callback. Sending negative response.", self.__log_prefix__()) status = STATUS_BUFFERING_UNHANDLED_REQUEST data = None else: try: self.logger.debug("%s RX <- Executing callback %s to process received data", self.__log_prefix__(), callback.__name__) status, data = callback(msg, *args, **kwargs) except Exception: logger.error('{lp} RX <- Exception raised. Check callback {callback_name} and it\'s return values for service_id {service_id} and data_id {data_id}'.format(lp=self.__log_prefix__(), callback_name=callback.__name__, service_id=repr(msg.get_service_id()), data_id=repr(msg.get_data_id()))) status = STATUS_CALLBACK_ERROR data = None else: # # RESPONSE RECEIVED # if callback is None: self.__buffer_received_data__(msg) else: self.logger.debug("%s Executing callback %s to process received data", self.__log_prefix__(), callback.__name__) callback(msg, *args, **kwargs) return # No response needed self.send(self.__sid_response_dict__[msg.get_service_id()], msg.get_data_id(), data, status=status) def __get_message_name__(self, service_id, data_id): return 'service: %s, data_id: %s' % ( self.__sid_name_dict__.get(service_id, repr(service_id)), self.__did_name_dict__.get(service_id, {}).get(data_id, repr(data_id)), ) def __get_status_name__(self, status): return 'status: %s' % (self.__status_name_dict.get(status, 'unknown status: %s' % repr(status))) def __init_channel_name__(self, channel_name): self.__comm_inst__.init_channel_name(channel_name) self.__callbacks__.init_channel_name(channel_name) if channel_name is None: self.logger = logging.getLogger(ROOT_LOGGER_NAME).getChild(__name__ + '.' + self.DEFAULT_CHANNEL_NAME) else: self.logger = logging.getLogger(ROOT_LOGGER_NAME).getChild(__name__ + '.' + channel_name) def __log_prefix__(self): return 'SP client:' if self.__comm_inst__.IS_CLIENT else 'SP server:' def __mk_msg__(self, status, service_id, data_id, data): return data_storage({data_storage.KEY_DATA_ID: data_id, data_storage.KEY_SERVICE_ID: service_id, data_storage.KEY_STATUS: status, data_storage.KEY_DATA: data}) def add_data(self, service_id, data_id, name): """ Method to add a name for a specific message. :param service_id: The Service-ID of the message. See class definitions starting with ``SID_``. :type service_id: int or list of ints :param data_id: The Data-ID of the message. :type data_id: int :param name: The Name for the transfered message. :type name: str """ try: iter(service_id) except Exception: service_id = (service_id, ) for sid in service_id: if sid not in self.__did_name_dict__: self.__did_name_dict__[sid] = {} self.__did_name_dict__[sid][data_id] = name def add_msg_to_auth_whitelist_(self, service_id, data_id): """ Method to add a specific message to the list, where no authentification is required. :param service_id: The Service-ID of the message. See class definitions starting with ``SID_``. :type service_id: int :param data_id: The Data-ID of the message. :type data_id: int """ if service_id not in self.__auth_whitelist__: self.__auth_whitelist__[service_id] = [] self.__auth_whitelist__[service_id].append(data_id) logger.debug('%s Adding Message (%s) to the authentification whitelist', self.__log_prefix__(), self.__get_message_name__(service_id, data_id)) def add_service(self, req_sid, resp_sid, req_name=None, resp_name=None): """ Method to add a Service defined by Request- and Response Serivce-ID. :param req_sid: The Request Service-ID. :type req_sid: int :param resp_sid: The Response Service-ID. :type resp_sid: int """ if req_sid in self.__sid_response_dict__: logger.error('%s Service with Request-SID=%d and Response-SID=%d not added, because request SID is already registered', self.__log_prefix__(), req_sid, resp_sid) raise RequestSidExistsError("Request for this Service is already registered") elif resp_sid in self.__sid_response_dict__.values(): logger.error('%s Service with Request-SID=%d and Response-SID=%d not added, because response SID is already registered', self.__log_prefix__(), req_sid, resp_sid) raise ResponseSidExistsError("Response for this Service is already registered") else: self.__sid_response_dict__[req_sid] = resp_sid if req_name is not None: self.__sid_name_dict__[req_sid] = req_name if resp_name is not None: self.__sid_name_dict__[resp_sid] = resp_name logger.debug('%s Adding Service with Request=%s and Response=%s', self.__log_prefix__(), req_name or repr(req_sid), resp_name or repr(resp_sid)) def add_status(self, status, name): """ Method to add a name for a status. :param status: The Status. See class definitions starting with ``STATUS_``. :type status: int :param name: The Name for the Status. :type name: str """ self.__status_name_dict[status] = name def authentificate(self, timeout=2): """ This method authetificates the client at the server. :param timeout: The timeout for the authentification (requesting seed, sending key and getting authentification_feedback). :type timeout: float :returns: True, if authentification was successfull; False, if not. :rtype: bool .. note:: An authentification will only processed, if a secret had been given on initialisation. .. note:: Client and Server needs to use the same secret. """ if self.__secret__ is not None: self.__authentification_state__ = AUTH_STATE_SEED_REQUESTED self.send(SID_AUTH_REQUEST, DID_AUTH_SEED, None) cnt = 0 while cnt < timeout * 10: time.sleep(0.1) if self.__authentification_state__ == AUTH_STATE_TRUSTED_CONNECTION: return True elif self.__authentification_state__ == AUTH_STATE_UNTRUSTED_CONNECTION: break cnt += 1 return False def check_authentification_state(self): """ This Method return the Authitification State as boolean value. :return: True, if authentification state is okay, otherwise False :rtype: bool """ return self.__secret__ is None or self.__authentification_state__ == AUTH_STATE_TRUSTED_CONNECTION def connection_established(self): """ This Method returns the Connection state including authentification as a boolean value. :return: True, if the connection is established (incl. authentification, if a secret has been given) :rtype: bool """ return self.is_connected() and (self.__secret__ is None or self.check_authentification_state()) def is_connected(self): """ This Methods returns Connection state of the Communication Instance :func:`comm_instance.is_connected`. :return: True if the :class:`comm_instance` is connected, otherwise False.. :rtype: bool """ return self.__comm_inst__.is_connected() def receive(self, service_id, data_id, timeout=1): """ This Method returns a message object for a defined message or None, if this message is not available after the given timout. :param service_id: The Service-ID for the message. See class definitions starting with ``SID_``. :type service_id: int :param data_id: The Data-ID for the message. :type data_id: int :param timeout: The timeout for receiving. :type timeout: float :returns: The received data storage object or None, if no data was received. :rtype: data_storage """ data = None cnt = 0 while data is None and cnt < timeout * 10: try: data = self.__msg_buffer__.get(service_id, {}).get(data_id, []).pop(0) except IndexError: data = None cnt += 1 time.sleep(0.1) if data is None and cnt >= timeout * 10: self.logger.warning('%s TIMEOUT (%ss): Requested data (service_id: %s; data_id: %s) not in buffer.', self.__log_prefix__(), repr(timeout), repr(service_id), repr(data_id)) return data def reconnect(self): """ This methods initiates a reconnect by calling :func:`comm_instance.reconnect`. """ return self.__comm_inst__.reconnect() def register_callback(self, service_id, data_id, callback, *args, **kwargs): """ This method registers a callback for the given parameters. Giving ``None`` means, that all Service-IDs or all Data-IDs are used. If a message hitting these parameters has been received, the callback will be executed. :param service_id: The Service-ID for the message. See class definitions starting with ``SID_``. :type service_id: int :param data_id: The Data-ID for the message. :type data_id: int .. note:: The :func:`callback` is priorised in the following order: * Callbacks with defined Service-ID and Data-ID. * Callbacks with a defined Service-ID and all Data-IDs. * Callbacks with a defined Data-ID and all Service-IDs. * Unspecific Callbacks. .. note:: The :func:`callback` is executed with these arguments: **Parameters given at the callback call:** * The first Arguments is the received message as :class:`data_storage` object. * Further arguments given at registration. * Further keyword arguments given at registration. **Return value of the callback:** If the Callback is a Request Callback for a registered Service, the return value has to be a tuple or list with * :const:`response_status`: The response status (see class definitions starting with :const:`STA_*`. * :const:`response_data`: A JSON iterable object to be used as data for the response. .. note:: Only registered services will respond via the callbacks return values with the same data_id. """ self.__callbacks__.add(service_id, data_id, callback, *args, **kwargs) def send(self, service_id, data_id, data, status=STATUS_OKAY, timeout=2): """ This methods sends out a message with the given content. :param service_id: The Service-ID for the message. See class definitions starting with ``SERVICE_``. :type service_id: int :param data_id: The Data-ID for the message. :type data_id: int :param data: The data to be transfered. The data needs to be json compatible. :type data: str :param status: The Status for the message. All requests should have ``STATUS_OKAY``. :type status: int :param timeout: The timeout for sending data (e.g. time to establish new connection). :type timeout: float :return: True if data had been sent, otherwise False. :rtype: bool """ if (self.check_authentification_state() or not self.__authentification_required__(service_id, data_id)) or (service_id in self.__sid_response_dict__.values() and status == STATUS_AUTH_REQUIRED and data is None): self.logger.info( '%s TX <- %s, %s, data: "%s"', self.__log_prefix__(), self.__get_message_name__(service_id, data_id), self.__get_status_name__(status), repr(data) ) return self.__comm_inst__.send(self.__build_frame__(service_id, data_id, data, status), timeout=timeout, log_lvl=logging.DEBUG) else: # Authentification required self.logger.warning("%s TX -> Authentification is required. Message %s, %s, data: %s will be ignored.", self.__log_prefix__(), self.__get_message_name__(service_id, data_id), self.__get_status_name__(status), repr(data)) return False class struct_json_protocol(pure_json_protocol): """ This Class has the same functionality like :class:`pure_json_protocol`. The message length is less than for :class:`pure_json_protocol`, but the functionality and compatibility is reduced. .. note:: This class is depreceated and here for compatibility reasons (to support old clients or servers). Usage of :class:`pure_json_protocol` is recommended. """ def __init__(self, *args, **kwargs): pure_json_protocol.__init__(self, *args, **kwargs) def __analyse_frame__(self, frame): status, service_id, data_id = struct.unpack('>III', frame[0:12]) if sys.version_info >= (3, 0): data = json.loads(frame[12:-1].decode('utf-8')) else: data = json.loads(frame[12:-1]) return self.__mk_msg__(status, service_id, data_id, data) def __build_frame__(self, service_id, data_id, data, status=STATUS_OKAY): frame = struct.pack('>III', status, service_id, data_id) if sys.version_info >= (3, 0): frame += bytes(json.dumps(data), 'utf-8') frame += self.__calc_chksum__(frame) else: frame += json.dumps(data) frame += self.__calc_chksum__(frame) return frame def __calc_chksum__(self, raw_data): chksum = 0 for b in raw_data: if sys.version_info >= (3, 0): chksum ^= b else: chksum ^= ord(b) if sys.version_info >= (3, 0): return bytes([chksum]) else: return chr(chksum) def __check_frame_checksum__(self, frame): return self.__calc_chksum__(frame[:-1]) == frame[-1:]