Added NFC backend

docs/source/conf.py

@@ -207,6 +207,8 @@ autodoc_mock_imports = ['googlesamples.assistant.grpc.audio_helpers',
                         'soundfile',
                         'numpy',
                         'cv2',
+                        'nfc',
+                        'ndef',
                         ]
 
 sys.path.insert(0, os.path.abspath('../..'))

platypush/backend/nfc.py

@@ -0,0 +1,187 @@
+import base64
+import json
+import nfc
+import ndef
+
+from platypush.backend import Backend
+from platypush.message.event.nfc import NFCTagDetectedEvent, NFCTagRemovedEvent, NFCDeviceConnectedEvent, \
+    NFCDeviceDisconnectedEvent
+
+
+class NfcBackend(Backend):
+    """
+    Backend to detect NFC card events from a compatible reader.
+
+    Triggers:
+
+        * :class:`platypush.message.event.nfc.NFCDeviceConnectedEvent` when an NFC reader/writer is connected
+        * :class:`platypush.message.event.nfc.NFCDeviceDisconnectedEvent` when an NFC reader/writer is disconnected
+        * :class:`platypush.message.event.nfc.NFCTagDetectedEvent` when an NFC tag is detected
+        * :class:`platypush.message.event.nfc.NFCTagRemovedEvent` when an NFC tag is removed
+
+    Requires:
+
+        * **nfcpy** >= 1.0 (``pip install nfcpy``)
+    """
+
+    def __init__(self, device='usb', *args, **kwargs):
+        """
+        :param device: Address or ID of the device to be opened. Examples:
+
+            * `'usb:003:009'` opens device 9 on bus 3
+            * `'usb:003'` opens the first available device on bus 3
+            * `'usb'` opens the first available USB device (default)
+        """
+
+        super().__init__(*args, **kwargs)
+
+        self.device_id = device
+        self._clf = None
+
+    def _get_clf(self):
+        if not self._clf:
+            self._clf = nfc.ContactlessFrontend()
+            self._clf.open(self.device_id)
+            self.bus.post(NFCDeviceConnectedEvent(reader=self._get_device_str()))
+            self.logger.info('Initialized NFC reader backend on device {}'.format(self._get_device_str()))
+
+        return self._clf
+
+    def _get_device_str(self):
+        return str(self._clf.device)
+
+    def close(self):
+        if self._clf:
+            self._clf.close()
+            self._clf = None
+            self.bus.post(NFCDeviceDisconnectedEvent(reader=self._get_device_str()))
+
+    @staticmethod
+    def _parse_records(tag):
+        records = []
+
+        for record in tag.ndef.records:
+            r = {
+                'record_type': record.type,
+                'record_name': record.name,
+            }
+
+            if isinstance(record, ndef.TextRecord):
+                try:
+                    r = {
+                        **r,
+                        'type': 'json',
+                        'value': json.loads(record.text),
+                    }
+                except ValueError:
+                    r = {
+                        **r,
+                        'type': 'text',
+                        'text': record.text,
+                    }
+            elif isinstance(record, ndef.UriRecord):
+                r = {
+                    **r,
+                    'type': 'uri',
+                    'uri': record.uri,
+                    'iri': record.iri,
+                }
+            elif isinstance(record, ndef.SmartposterRecord):
+                r = {
+                    **r,
+                    'type': 'smartposter',
+                    **{attr: getattr(record, attr) for attr in ['resource', 'titles', 'title', 'action', 'icon',
+                                                                'icons', 'resource_size', 'resource_type']},
+                }
+            elif isinstance(record, ndef.DeviceInformationRecord):
+                r = {
+                    **r,
+                    'type': 'device_info',
+                    **{attr: getattr(record, attr) for attr in ['vendor_name', 'model_name', 'unique_name',
+                                                                'uuid_string', 'version_string']},
+                }
+            elif isinstance(record, ndef.WifiSimpleConfigRecord):
+                r = {
+                    **r,
+                    'type': 'wifi_simple_config',
+                    **{attr: record[attr] for attr in record.attribute_names()}
+                }
+            elif isinstance(record, ndef.WifiPeerToPeerRecord):
+                r = {
+                    **r,
+                    'type': 'wifi_peer_to_peer',
+                    **{attr: record[attr] for attr in record.attribute_names()}
+                }
+            elif isinstance(record, ndef.BluetoothEasyPairingRecord):
+                r = {
+                    **r,
+                    'type': 'bluetooth_easy_pairing',
+                    **{attr: getattr(record, attr) for attr in ['device_address', 'device_name', 'device_class']},
+                }
+            elif isinstance(record, ndef.BluetoothLowEnergyRecord):
+                r = {
+                    **r,
+                    'type': 'bluetooth_low_energy',
+                    **{attr: getattr(record, attr) for attr in ['device_address', 'device_name', 'role_capabilities',
+                                                                'appearance', 'flags', 'security_manager_tk_value',
+                                                                'secure_connections_confirmation_value',
+                                                                'secure_connections_random_value']},
+                }
+            elif isinstance(record, ndef.SignatureRecord):
+                r = {
+                    **r,
+                    'type': 'signature',
+                    **{attr: getattr(record, attr) for attr in ['version', 'signature_type', 'hash_type', 'signature',
+                                                                'signature_uri', 'certificate_format',
+                                                                'certificate_store', 'certificate_uri',
+                                                                'secure_connections_random_value']},
+                }
+            else:
+                r = {
+                    **r,
+                    'type': 'binary',
+                    'data': base64.encodebytes(record.data).decode(),
+                }
+
+            records.append(r)
+
+        return records
+
+    @staticmethod
+    def _parse_id(tag):
+        return ''.join([('%02X' % c) for c in tag.identifier])
+
+    def _on_connect(self):
+        def callback(tag):
+            if not tag:
+                return False
+
+            tag_id = self._parse_id(tag)
+            records = self._parse_records(tag)
+            self.bus.post(NFCTagDetectedEvent(reader=self._get_device_str(), tag_id=tag_id, records=records))
+            return True
+
+        return callback
+
+    def _on_release(self):
+        def callback(tag):
+            tag_id = self._parse_id(tag)
+            self.bus.post(NFCTagRemovedEvent(reader=self._get_device_str(), tag_id=tag_id))
+
+        return callback
+
+    def run(self):
+        super().run()
+
+        while not self.should_stop():
+            try:
+                clf = self._get_clf()
+                clf.connect(rdwr={
+                    'on-connect': self._on_connect(),
+                    'on-release': self._on_release(),
+                })
+            finally:
+                self.close()
+
+
+# vim:sw=4:ts=4:et:

platypush/message/event/nfc.py

@@ -0,0 +1,80 @@
+import json
+
+from platypush.message.event import Event
+
+
+class NFCEvent(Event):
+    """
+    Generic class for NFC events
+    """
+
+    def __init__(self, reader=None, tag_id=None, *args, **kwargs):
+        super().__init__(reader=reader, tag_id=tag_id, *args, **kwargs)
+
+
+class NFCDeviceConnectedEvent(NFCEvent):
+    """
+    Event triggered when an NFC reader/writer devices is connected
+    """
+
+    def __init__(self, reader=None, *args, **kwargs):
+        """
+        :param reader: Name or address of the reader that fired the event
+        :type reader: str
+        """
+        super().__init__(reader=reader, *args, **kwargs)
+
+
+class NFCDeviceDisconnectedEvent(NFCEvent):
+    """
+    Event triggered when an NFC reader/writer devices is disconnected
+    """
+
+    def __init__(self, reader=None, *args, **kwargs):
+        """
+        :param reader: Name or address of the reader that fired the event
+        :type reader: str
+        """
+        super().__init__(reader=reader, *args, **kwargs)
+
+
+class NFCTagDetectedEvent(NFCEvent):
+    """
+    Event triggered when an NFC tag is connected
+    """
+
+    def __init__(self, reader=None, tag_id=None, records=None, *args, **kwargs):
+        """
+        :param reader: Name or address of the reader that fired the event
+        :type reader: str
+
+        :param tag_id: ID of the NFC tag
+        :type tag_id: str
+
+        :param records: Optional, list of records read from the tag. If the tag contains JSON-serializable data then it
+            will be cast by the backend into the appropriate object
+        :type records: str, bytes or JSON-serializable object
+        """
+        if not records:
+            records = []
+
+        super().__init__(reader=reader, tag_id=tag_id, records=records, *args, **kwargs)
+
+
+class NFCTagRemovedEvent(NFCEvent):
+    """
+    Event triggered when a NFC card is removed/disconnected
+    """
+
+    def __init__(self, reader=None, tag_id=None, *args, **kwargs):
+        """
+        :param reader: Name or address of the reader that fired the event
+        :type reader: str
+
+        :param tag_id: ID of the NFC tag
+        :type tag_id: str
+        """
+        super().__init__(reader=reader, tag_id=tag_id, *args, **kwargs)
+
+
+# vim:sw=4:ts=4:et:

platypush/message/request/__init__.py

@@ -5,7 +5,6 @@ import logging
 import random
 import re
 import time
-import traceback
 
 from threading import Thread
 
@@ -48,25 +47,20 @@ class Request(Message):
     @classmethod
     def build(cls, msg):
         msg = super().parse(msg)
-        args = {
+        args = {'target': msg.get('target', Config.get('device_id')), 'action': msg['action'],
-            'target' : msg.get('target', Config.get('device_id')),
+                'args': msg.get('args', {}), 'id': msg['id'] if 'id' in msg else cls._generate_id(),
-            'action' : msg['action'],
+                'timestamp': msg['_timestamp'] if '_timestamp' in msg else time.time()}
-            'args'   : msg['args'] if 'args' in msg else {},
-        }
 
-        args['id'] = msg['id'] if 'id' in msg else cls._generate_id()
-        args['timestamp'] = msg['_timestamp'] if '_timestamp' in msg else time.time()
         if 'origin' in msg: args['origin'] = msg['origin']
         if 'token' in msg: args['token'] = msg['token']
         return cls(**args)
 
     @staticmethod
     def _generate_id():
-        id = ''
+        _id = ''
-        for i in range(0,16):
+        for i in range(0, 16):
-            id += '%.2x' % random.randint(0, 255)
+            _id += '%.2x' % random.randint(0, 255)
-        return id
+        return _id
-
 
     def _execute_procedure(self, *args, **kwargs):
         from platypush.config import Config
@@ -81,7 +75,6 @@ class Request(Message):
 
         return proc.execute(*args, **kwargs)
 
-
     def _expand_context(self, event_args=None, **context):
         from platypush.config import Config
 
@@ -110,7 +103,6 @@ class Request(Message):
 
         return event_args
 
-
     @classmethod
     def expand_value_from_context(cls, _value, **context):
         for (k, v) in context.items():
@@ -130,10 +122,12 @@ class Request(Message):
             parsed_value = _value
 
         while _value and isinstance(_value, str):
-            m = re.match('([^\$]*)(\${\s*(.+?)\s*})(.*)', _value)
+            m = re.match('([^$]*)(\${\s*(.+?)\s*})(.*)', _value)
             if m and not m.group(1).endswith('\\'):
-                prefix = m.group(1); expr = m.group(2);
+                prefix = m.group(1)
-                inner_expr = m.group(3); _value = m.group(4)
+                expr = m.group(2)
+                inner_expr = m.group(3)
+                _value = m.group(4)
 
                 try:
                     context_value = eval(inner_expr)
@@ -155,9 +149,10 @@ class Request(Message):
                 parsed_value += _value
                 _value = ''
 
-        try: return json.loads(parsed_value)
+        try:
-        except Exception as e: return parsed_value
+            return json.loads(parsed_value)
-
+        except:
+            return parsed_value
 
     def _send_response(self, response):
         response = Response.build(response)
@@ -174,7 +169,6 @@ class Request(Message):
                 redis.send_message(queue_name, response)
                 redis.expire(queue_name, 60)
 
-
     def execute(self, n_tries=1, _async=True, **context):
         """
         Execute this request and returns a Response object
@@ -190,44 +184,48 @@ class Request(Message):
                     - group: ${group_name}  # will be expanded as "Kitchen lights")
         """
 
-        def _thread_func(n_tries, errors=None):
+        def _thread_func(_n_tries, errors=None):
+            response = None
+
             if self.action.startswith('procedure.'):
-                context['n_tries'] = n_tries
+                context['n_tries'] = _n_tries
                 response = self._execute_procedure(**context)
                 if response is not None:
                     self._send_response(response)
                 return response
             else:
-                (module_name, method_name) = get_module_and_method_from_action(self.action)
+                action = self.expand_value_from_context(self.action, **context)
+                (module_name, method_name) = get_module_and_method_from_action(action)
                 plugin = get_plugin(module_name)
 
             try:
                 # Run the action
                 args = self._expand_context(**context)
+                args = self.expand_value_from_context(args, **context)
                 response = plugin.run(method=method_name, **args)
 
                 if response and response.is_error():
                     logger.warning(('Response processed with errors from ' +
                                     'action {}: {}').format(
-                                        self.action, str(response)))
+                        action, str(response)))
                 elif not response.disable_logging:
                     logger.info('Processed response from action {}: {}'.
-                                format(self.action, str(response)))
+                                format(action, str(response)))
             except Exception as e:
                 # Retry mechanism
                 plugin.logger.exception(e)
                 logger.warning(('Uncaught exception while processing response ' +
-                                'from action [{}]: {}').format(self.action, str(e)))
+                                'from action [{}]: {}').format(action, str(e)))
 
                 errors = errors or []
                 if str(e) not in errors:
                     errors.append(str(e))
 
                 response = Response(output=None, errors=errors)
-                if n_tries-1 > 0:
+                if _n_tries-1 > 0:
                     logger.info('Reloading plugin {} and retrying'.format(module_name))
                     get_plugin(module_name, reload=True)
-                    response = _thread_func(n_tries=n_tries-1, errors=errors)
+                    response = _thread_func(_n_tries=_n_tries - 1, errors=errors)
             finally:
                 self._send_response(response)
                 return response
@@ -243,7 +241,6 @@ class Request(Message):
         else:
             return _thread_func(n_tries)
 
-
     def __str__(self):
         """
         Overrides the str() operator and converts
@@ -251,16 +248,15 @@ class Request(Message):
         """
 
         return json.dumps({
-            'type'   : 'request',
+            'type': 'request',
-            'target' : self.target,
+            'target': self.target,
-            'action' : self.action,
+            'action': self.action,
-            'args'   : self.args,
+            'args': self.args,
-            'origin' : self.origin if hasattr(self, 'origin') else None,
+            'origin': self.origin if hasattr(self, 'origin') else None,
-            'id'     : self.id if hasattr(self, 'id') else None,
+            'id': self.id if hasattr(self, 'id') else None,
-            'token'  : self.token if hasattr(self, 'token') else None,
+            'token': self.token if hasattr(self, 'token') else None,
-            '_timestamp' : self.timestamp,
+            '_timestamp': self.timestamp,
         })
 
 
 # vim:sw=4:ts=4:et:
-

requirements.txt

@@ -133,8 +133,12 @@ inputs
 websocket-client
 
 # mpv player plugin
-python-mpv
+# python-mpv
 
 # SCSS/SASS to CSS compiler for web pages style
 pyScss
 
+# Support for NFC tags
+# nfcpy >= 1.0
+# ndef
+

setup.py

@@ -169,6 +169,7 @@ setup(
         'Support for mopidy backend': ['websocket-client'],
         'Support for mpv player plugin': ['python-mpv'],
         'Support for compiling SASS/SCSS styles to CSS': ['pyScss'],
+        'Support for NFC tags': ['nfcpy>=1.0', 'ndef'],
         # 'Support for Leap Motion backend': ['git+ssh://git@github.com:BlackLight/leap-sdk-python3.git'],
         # 'Support for Flic buttons': ['git+https://@github.com/50ButtonsEach/fliclib-linux-hci.git']
         # 'Support for media subtitles': ['git+https://github.com/agonzalezro/python-opensubtitles#egg=python-opensubtitles']