ble_transport: Fixed a BLE characteristic caching issue.

Root cause: Android's BLE stack caches all characteristics received from peripheral. Even if peripheral has removed characteristics, app gets that characteristic from the cached data, but will not be able to communicate on that characteristic. This results in device communication failure. Solution: Added API to refresh services. Also ignored the characteristic whose descriptor data is null.
playmoweb · Oct 26, 2021 · 4285429 · 4285429
1 parent cf458ca
commit 4285429
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diff --git a/README.md b/README.md
@@ -47,7 +47,7 @@ To get this app please clone this repository using the below command:
  ```
 And add a dependency code to your  app module's  `build.gradle`  file. 
 ```  
- implementation 'com.github.espressif:esp-idf-provisioning-android:lib-2.0.10'
+ implementation 'com.github.espressif:esp-idf-provisioning-android:lib-2.0.11'
 ```
 
 ## Using Provisioning Library

diff --git a/app/build.gradle b/app/build.gradle
@@ -17,8 +17,8 @@ android {
         applicationId "com.espressif.wifi_provisioning"
         minSdkVersion 23
         targetSdkVersion 30
-        versionCode 13
-        versionName "2.0.10 - ${getGitHash()}"
+        versionCode 14
+        versionName "2.0.11 - ${getGitHash()}"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }
 

diff --git a/provisioning/src/main/java/com/espressif/provisioning/ESPDevice.java b/provisioning/src/main/java/com/espressif/provisioning/ESPDevice.java
@@ -318,6 +318,13 @@ public void disconnectDevice() {
         disableOnlyWifiNetwork();
     }
 
+    public void refreshServicesOfBleDevice() {
+
+        if (transport instanceof BLETransport) {
+            ((BLETransport) transport).refreshServices();
+        }
+    }
+
     /**
      * This method is used to set Proof Of Possession.
      *

diff --git a/provisioning/src/main/java/com/espressif/provisioning/transport/BLETransport.java b/provisioning/src/main/java/com/espressif/provisioning/transport/BLETransport.java
@@ -35,6 +35,7 @@
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import java.lang.reflect.Method;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -154,6 +155,20 @@ public void disconnect() {
         }
     }
 
+    public void refreshServices() {
+        Log.e(TAG, "Refresh services...");
+        try {
+            // BluetoothGatt gatt
+            final Method refresh = bluetoothGatt.getClass().getMethod("refresh");
+            if (refresh != null) {
+                refresh.invoke(bluetoothGatt);
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+        bluetoothGatt.discoverServices();
+    }
+
     private BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
 
         @Override
@@ -186,6 +201,7 @@ public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState
         public void onServicesDiscovered(BluetoothGatt gatt, int status) {
 
             super.onServicesDiscovered(gatt, status);
+            Log.d(TAG, "On services discovered");
 
             if (status != BluetoothGatt.GATT_SUCCESS) {
                 Log.d(TAG, "Status not success");
@@ -233,19 +249,25 @@ public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descri
         @Override
         public void onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) {
 
-            Log.d(TAG, "DescriptorRead, : Status " + status + " Data : " + new String(descriptor.getValue(), StandardCharsets.UTF_8));
+            Log.d(TAG, "DescriptorRead, : Status " + status);
+            byte[] data = descriptor.getValue();
+            String charUuid = descriptor.getCharacteristic().getUuid().toString();
 
             if (status != BluetoothGatt.GATT_SUCCESS) {
                 Log.e(TAG, "Failed to read descriptor");
-                EventBus.getDefault().post(new DeviceConnectionEvent(ESPConstants.EVENT_DEVICE_CONNECTION_FAILED));
-                return;
+                charUuidList.remove(charUuid);
+//                EventBus.getDefault().post(new DeviceConnectionEvent(ESPConstants.EVENT_DEVICE_CONNECTION_FAILED));
+//                return;
             }
 
-            byte[] data = descriptor.getValue();
-
-            String value = new String(data, StandardCharsets.UTF_8);
-            uuidMap.put(value, descriptor.getCharacteristic().getUuid().toString());
-            Log.d(TAG, "Value : " + value + " for UUID : " + descriptor.getCharacteristic().getUuid().toString());
+            if (data == null) {
+                Log.e(TAG, "Descriptor value is null");
+                charUuidList.remove(charUuid);
+            } else {
+                String value = new String(data, StandardCharsets.UTF_8);
+                uuidMap.put(value, charUuid);
+                Log.d(TAG, "DescriptorRead, Value : " + value + " for UUID : " + charUuid);
+            }
 
             if (isReadingDescriptors) {