BLESession: Add _getDevName() helper function

GitHub issue #31 reported that Intelino Smart Train is not connected
with pyscrlink. It also reported that getValueText(0x9) call for the
device instead of getValueText(0x8) avoids the failure. This implies
that the Intelino Smart Train does not report AdType 0x8 "Shortened
local name" but it reports AdType 0x9 "Complete local name".

To get local name of the BLE devices regardless AdType support status
of those devices, introduce a helper function _getDevName(). It gets the
AdType 0x9 "Complete local name" first. If it is not available, get
AdType 0x8 "Shortened local name". Use this helper function at all
places to get the device name.

Signed-off-by: Shin'ichiro Kawasaki <[email protected]>

pyscrlink/scratch_link.py

@@ -362,6 +362,14 @@ class BLESession(Session):
     scan_lock = threading.RLock()
     scan_started = False
 
+    @staticmethod
+    def _getDevName(dev):
+        """
+        Get AdType 0x09 (Completed local name). If it is not available,
+        get AdType 0x08 (Shortened local name).
+        """
+        return dev.getValueText(0x9) or dev.getValueText(0x8)
+
     class BLEThread(threading.Thread):
         """
         Separated thread to control notifications to Scratch.
@@ -381,7 +389,7 @@ def run(self):
                     for d in devices:
                         params = { 'rssi': d.rssi }
                         params['peripheralId'] = devices.index(d)
-                        params['name'] = d.getValueText(0x9) or d.getValueText(0x8)
+                        params['name'] = BLESession._getDevName(d)
                         self.session.notify('didDiscoverPeripheral', params)
                     time.sleep(1)
                 elif self.session.status == self.session.CONNECTED:
@@ -504,7 +512,7 @@ def matches(self, dev, filters):
                             return True
             if 'namePrefix' in f:
                 # 0x08: Shortened Local Name
-                deviceName = dev.getValueText(0x08)
+                deviceName = self._getDevName(dev)
                 if not deviceName:
                     continue
                 logger.debug(f"Name of \"{deviceName}\" begins with: \"{f['namePrefix']}\"?")
@@ -620,7 +628,7 @@ def handle_request(self, method, params):
         elif self.status == self.DISCOVERY and method == 'connect':
             logger.debug("connecting to the BLE device")
             self.device = BLESession.found_devices[params['peripheralId']]
-            self.deviceName = self.device.getValueText(0x9) or self.device.getValueText(0x8)
+            self.deviceName = self._getDevName(self.device)
             try:
                 self.perip = Peripheral(self.device)
                 logger.info(f"connected to the BLE peripheral: {self.deviceName}")