BluetoothGattCharacteristic

Description

The BluetoothGattCharacteristic interface of the Bluetooth API represents a GATT service characteristic, which includes characteristic definition, value, properties and configuration info, and a list of descriptors that provide related information.

Interface overview

[Exposed=Window]

interface BluetoothGattCharacteristic

{

readonly attribute BluetoothGattService service;

[Cached, Pure] readonly attribute sequence<BluetoothGattDescriptor> descriptors;

readonly attribute DOMString uuid;

readonly attribute unsigned short instanceId;

readonly attribute ArrayBuffer? value;

[Cached, Constant] readonly attribute GattPermissions permissions;

[Cached, Constant] readonly attribute GattCharacteristicProperties properties;

[NewObject] Promise<ArrayBuffer> readValue();

[NewObject] Promise<void> writeValue(ArrayBuffer value);

[NewObject] Promise<void> startNotifications();

[NewObject] Promise<void> stopNotifications();

[NewObject] Promise<BluetoothGattDescriptor> addDescriptor(DOMString uuid, GattPermissions permissions, ArrayBuffer value);

};

dictionary GattPermissions

{

boolean read = false;

boolean readEncrypted = false;

boolean readEncryptedMITM = false;

boolean write = false;

boolean writeEncrypted = false;

boolean writeEncryptedMITM = false;

boolean writeSigned = false;

boolean writeSignedMITM = false;

};

dictionary GattCharacteristicProperties

{

boolean broadcast = false;

boolean read = false;

boolean writeNoResponse = false;

boolean write = false;

boolean notify = false;

boolean indicate = false;

boolean signedWrite = false;

boolean extendedProps = false;

};

Properties

• BluetoothGattCharacteristic.service read-only Returns the BluetoothGattService that this characteristic belongs to.

• BluetoothGattCharacteristic.descriptors read-only Returns a cached array containing the BluetoothGattDescriptor objects that describe this characteristic.

• BluetoothGattCharacteristic.uuid read-only Returns a DOMString representing the UUID of this characteristic.

• BluetoothGattCharacteristic.instanceId read-only Returns a number representing the instance id of this characteristic.

• BluetoothGattCharacteristic.value read-only Returns The cached value of this characteristic as an ArrayBuffer. This value can be updated via the BluetoothGattCharacteristic.readValue() method, characteristic notification, or indication from the remote device.

• BluetoothGattCharacteristic.permissions read-only Returns a GattPermissions that describes the operations permitted on this characteristic.

• BluetoothGattCharacteristic.properties read-only Returns a GattCharacteristicProperties that describes how to use the characteristic value.

Methods

• BluetoothGattCharacteristic.readValue() Reads the characteristic value from the remote device. The cached value property will also be updated after retrieving the value.

• BluetoothGattCharacteristic.writeValue() Writes the characteristic value to the GATT server. If the local device is the GATT client, the value will be written to the remote GATT server. On the other hand, if the local device is the GATT server, the value will be written to BluetoothGattCharacteristic.value.

• BluetoothGattCharacteristic.startNotifications() Registers notifications/indications for this characteristic.

• BluetoothGattCharacteristic.stopNotifications() Unregisters notifications/indications for this characteristic.

• BluetoothGattCharacteristic.addDescriptor() Adds a descriptor to this characteristic.