Merge pull request #89 from dhalbert/easier-prefixes

Easier specification of prefixes; fixes for use with bleak

Author: tannewt

adafruit_ble/__init__.py

@@ -231,7 +231,7 @@ def start_scan(
         """
         if not advertisement_types:
             advertisement_types = (Advertisement,)
-        prefixes = b"".join(adv.prefix for adv in advertisement_types)
+        prefixes = b"".join(adv.get_prefix_bytes() for adv in advertisement_types)
         for entry in self._adapter.start_scan(
             prefixes=prefixes,
             buffer_size=buffer_size,
@@ -261,7 +261,7 @@ def stop_scan(self):
            once empty."""
         self._adapter.stop_scan()
 
-    def connect(self, advertisement, *, timeout=4):
+    def connect(self, advertisement, *, timeout=4.0):
         """
         Initiates a `BLEConnection` to the peer that advertised the given advertisement.
 

adafruit_ble/advertising/__init__.py

@@ -103,6 +103,8 @@ def __init__(self, bit_position):
         self._bitmask = 1 << bit_position
 
     def __get__(self, obj, cls):
+        if obj is None:
+            return self
         return (obj.flags & self._bitmask) != 0
 
     def __set__(self, obj, value):
@@ -214,9 +216,17 @@ def advertising_data_type(self):
 
 
 class Advertisement:
-    """Core Advertisement type"""
+    """Core Advertisement type.
+
+    The class attribute ``match_prefixes``, if not ``None``, is a tuple of
+    bytestring prefixes to match against the multiple data structures in the advertisement.
+    """
+
+    match_prefixes = ()
+    """For Advertisement, `matches` will always return True. Subclasses may override this value."""
+    # cached bytes of merged prefixes.
+    _prefix_bytes = None
 
-    prefix = b"\x00"  # This is an empty prefix and will match everything.
     flags = LazyObjectField(AdvertisingFlags, "flags", advertising_data_type=0x01)
     short_name = String(advertising_data_type=0x08)
     """Short local device name (shortened to fit)."""
@@ -257,7 +267,11 @@ def from_entry(cls, entry):
         """Create an Advertisement based on the given ScanEntry. This is done automatically by
            `BLERadio` for all scan results."""
         self = cls()
-        self.data_dict = decode_data(entry.advertisement_bytes)
+        # If data_dict is available, use it directly. Otherwise decode the bytestring.
+        if hasattr(entry, "data_dict"):
+            self.data_dict = entry.data_dict
+        else:
+            self.data_dict = decode_data(entry.advertisement_bytes)
         self.address = entry.address
         self._rssi = entry.rssi  # pylint: disable=protected-access
         self.connectable = entry.connectable
@@ -271,14 +285,43 @@ def rssi(self):
            from `BLERadio.start_scan()`. (read-only)"""
         return self._rssi
 
+    @classmethod
+    def get_prefix_bytes(cls):
+        """Return a merged version of match_prefixes as a single bytes object,
+        with length headers.
+        """
+        # Check for deprecated `prefix` class attribute.
+        cls._prefix_bytes = getattr(cls, "prefix", None)
+        # Do merge once and memoize it.
+        if cls._prefix_bytes is None:
+            cls._prefix_bytes = (
+                b""
+                if cls.match_prefixes is None
+                else b"".join(
+                    len(prefix).to_bytes(1, "little") + prefix
+                    for prefix in cls.match_prefixes
+                )
+            )
+
+        return cls._prefix_bytes
+
     @classmethod
     def matches(cls, entry):
-        """Returns true if the given `_bleio.ScanEntry` matches all portions of the Advertisement
-           type's prefix."""
-        if not hasattr(cls, "prefix"):
-            return True
+        """Returns ``True`` if the given `_bleio.ScanEntry` advertisement fields
+        matches all of the given prefixes in the `match_prefixes` tuple attribute.
+        Subclasses may override this to match any instead of all.
+        """
+        return cls.matches_prefixes(entry, all_=True)
 
-        return entry.matches(cls.prefix)
+    @classmethod
+    def matches_prefixes(cls, entry, *, all_):
+        """Returns ``True`` if the given `_bleio.ScanEntry` advertisement fields
+        match any or all of the given prefixes in the `match_prefixes` tuple attribute.
+        If ``all_`` is ``True``, all the prefixes must match. If ``all_`` is ``False``,
+        returns ``True`` if at least one of the prefixes match.
+        """
+        # Returns True if cls.get_prefix_bytes() is empty.
+        return entry.matches(cls.get_prefix_bytes(), all=all_)
 
     def __bytes__(self):
         """The raw packet bytes."""

adafruit_ble/advertising/adafruit.py

@@ -48,14 +48,15 @@
 class AdafruitColor(Advertisement):
     """Broadcast a single RGB color."""
 
-    # This prefix matches all
-    prefix = struct.pack(
-        "<BBHBH",
-        0x6,
-        _MANUFACTURING_DATA_ADT,
-        _ADAFRUIT_COMPANY_ID,
-        struct.calcsize("<HI"),
-        _COLOR_DATA_ID,
+    # This single prefix matches all color advertisements.
+    match_prefixes = (
+        struct.pack(
+            "<BHBH",
+            _MANUFACTURING_DATA_ADT,
+            _ADAFRUIT_COMPANY_ID,
+            struct.calcsize("<HI"),
+            _COLOR_DATA_ID,
+        ),
     )
     manufacturer_data = LazyObjectField(
         ManufacturerData,

adafruit_ble/advertising/apple.py

@@ -1,5 +1,6 @@
 # class iBeacon(Advertisement):
-#     prefix = b"\xff\x00\x4c\x02" # Apple manufacturer data with subtype 2
+#     # Apple manufacturer data with subtype 2
+#     match_prefixes = (b"\xff\x00\x4c\x02",)
 #
 #     proximity_uuid =
 #     major =

adafruit_ble/advertising/standard.py

@@ -135,7 +135,7 @@ def __str__(self):
             data.append(str(service_uuid))
         for service_uuid in self._vendor_services:
             data.append(str(service_uuid))
-        return " ".join(data)
+        return "<BoundServiceList: {}>".format(", ".join(data))
 
 
 class ServiceList(AdvertisingDataField):
@@ -155,8 +155,10 @@ def _present(self, obj):
         return False
 
     def __get__(self, obj, cls):
+        if obj is None:
+            return self
         if not self._present(obj) and not obj.mutable:
-            return None
+            return ()
         if not hasattr(obj, "adv_service_lists"):
             obj.adv_service_lists = {}
         first_adt = self.standard_services[0]
@@ -168,8 +170,8 @@ def __get__(self, obj, cls):
 class ProvideServicesAdvertisement(Advertisement):
     """Advertise what services that the device makes available upon connection."""
 
-    # This is four prefixes, one for each ADT that can carry service UUIDs.
-    prefix = b"\x01\x02\x01\x03\x01\x06\x01\x07"
+    # Prefixes that match each ADT that can carry service UUIDs.
+    match_prefixes = (b"\x02", b"\x03", b"\x06", b"\x07")
     services = ServiceList(standard_services=[0x02, 0x03], vendor_services=[0x06, 0x07])
     """List of services the device can provide."""
 
@@ -183,14 +185,17 @@ def __init__(self, *services):
 
     @classmethod
     def matches(cls, entry):
-        return entry.matches(cls.prefix, all=False)
+        """Only one kind of service list need be present in a ProvideServicesAdvertisement,
+        so override the default behavior and match any prefix, not all.
+        """
+        return cls.matches_prefixes(entry, all_=False)
 
 
 class SolicitServicesAdvertisement(Advertisement):
     """Advertise what services the device would like to use over a connection."""
 
-    # This is two prefixes, one for each ADT that can carry solicited service UUIDs.
-    prefix = b"\x01\x14\x01\x15"
+    # Prefixes that match each ADT that can carry solicited service UUIDs.
+    match_prefixes = (b"\x14", b"\x15")
 
     solicited_services = ServiceList(standard_services=[0x14], vendor_services=[0x15])
     """List of services the device would like to use."""
@@ -314,7 +319,11 @@ def __init__(self, service):
             self._adt = 0x21
         self._prefix = bytes(service.uuid)
 
-    def __get__(self, obj, cls):
+    def __get__(
+        self, obj, cls
+    ):  # pylint: disable=too-many-return-statements,too-many-branches
+        if obj is None:
+            return self
         # If not present at all and mutable, then we init it, otherwise None.
         if self._adt not in obj.data_dict:
             if obj.mutable:

adafruit_ble/characteristics/__init__.py

@@ -151,6 +151,10 @@ def __bind_locally(self, service, initial_value):
         )
 
     def __get__(self, service, cls=None):
+        # CircuitPython doesn't invoke descriptor protocol on obj's class,
+        # but CPython does. In the CPython case, pretend that it doesn't.
+        if service is None:
+            return self
         self._ensure_bound(service)
         bleio_characteristic = service.bleio_characteristics[self.field_name]
         return bleio_characteristic.value
@@ -210,6 +214,8 @@ def bind(self, service):
         )
 
     def __get__(self, service, cls=None):
+        if service is None:
+            return self
         bound_object = self.bind(service)
         setattr(service, self.field_name, bound_object)
         return bound_object
@@ -253,6 +259,8 @@ def __init__(
         )
 
     def __get__(self, obj, cls=None):
+        if obj is None:
+            return self
         raw_data = super().__get__(obj, cls)
         if len(raw_data) < self._expected_size:
             return None

adafruit_ble/characteristics/float.py

@@ -58,6 +58,8 @@ def __init__(
         )
 
     def __get__(self, obj, cls=None):
+        if obj is None:
+            return self
         return super().__get__(obj)[0]
 
     def __set__(self, obj, value):

adafruit_ble/characteristics/int.py

@@ -66,6 +66,8 @@ def __init__(
         )
 
     def __get__(self, obj, cls=None):
+        if obj is None:
+            return self
         return super().__get__(obj)[0]
 
     def __set__(self, obj, value):

adafruit_ble/characteristics/string.py

@@ -57,6 +57,8 @@ def __init__(
         )
 
     def __get__(self, obj, cls=None):
+        if obj is None:
+            return self
         return str(super().__get__(obj, cls), "utf-8")
 
     def __set__(self, obj, value):
@@ -76,4 +78,6 @@ def __init__(self, *, uuid=None, read_perm=Attribute.OPEN):
         )
 
     def __get__(self, obj, cls=None):
+        if obj is None:
+            return self
         return str(super().__get__(obj, cls), "utf-8")

adafruit_ble/services/standard/device_info.py

@@ -29,7 +29,6 @@
 import binascii
 import os
 import sys
-import microcontroller
 
 from .. import Service
 from ...uuid import StandardUUID
@@ -65,11 +64,16 @@ def __init__(
             if model_number is None:
                 model_number = sys.platform
             if serial_number is None:
-                serial_number = binascii.hexlify(
-                    microcontroller.cpu.uid  # pylint: disable=no-member
-                ).decode("utf-8")
+                try:
+                    import microcontroller  # pylint: disable=import-outside-toplevel
+
+                    serial_number = binascii.hexlify(
+                        microcontroller.cpu.uid  # pylint: disable=no-member
+                    ).decode("utf-8")
+                except ImportError:
+                    pass
             if firmware_revision is None:
-                firmware_revision = os.uname().version
+                firmware_revision = getattr(os.uname(), "version", None)
         super().__init__(
             manufacturer=manufacturer,
             software_revision=software_revision,