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B2G/Bluetooth/WebBluetooth-v2/BluetoothGattCharacteristic

< B2G‎ | Bluetooth‎ | WebBluetooth-v2
Revision as of 06:06, 20 November 2014 by Btian (talk | contribs) (→‎BluetoothGattCharacteristic)

Overview

BluetoothGattCharacteristic represents the characteristic of services. BluetoothGattCharacteristic consists of the characteristic definition, a characteristic value along with properties and configurations which indicate how to access the value, and a list of descriptors which provides related information of this characteristic value.

Interfaces

BluetoothGattCharacteristic

[CheckPermissions="bluetooth"]
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 Permissions permissions;
  [Cached, Constant]
  readonly attribute Properties properties;
  [Cached, Pure]         
           attribute WriteType writeType;

  [NewObject, Throws] Promise<ArrayBuffer> readValue();
  [NewObject, Throws] Promise<ArrayBuffer> writeValue(ArrayBuffer value);
  [NewObject, Throws] Promise<void> startNotifications();
  [NewObject, Throws] Promise<void> stopNotifications();
  [NewObject, Throws] Promise<BluetoothGattDescriptor> addDescriptor(DOMString aUuid, Permissions aDescriptorPermissions);
};

Permissions

dictionary Permissions
{
  required boolean read;
  required boolean readEncrypted;
  required boolean readEncryptedMITM;
  required boolean write;
  required boolean writeEncrypted;
  required boolean writeEncryptedMITM;
  required boolean writeSigned;
  required boolean writeSignedMITM;
};

Properties

dictionary Properties
{
  required boolean broadcast;
  required boolean read;
  required boolean writeNoResponse;
  required boolean write;
  required boolean notify;
  required boolean indicate;
  required boolean signedWrite;
  required boolean extendedProps;
};

WriteType

dictionary WriteType
{
  required boolean noResponse;
  required boolean default;
  required boolean signed;
};

Properties

service

Description
The service which this characteristic belongs to.
Value Type
BluetoothGattService
Default Value
null pointer

descriptors

Description
A cached descriptor array of this characteristic.
Value Type
sequence<BluetoothGattDescriptor>
Default Value
Empty array (array with length = 0)

uuid

Description
This property stores the UUID of this characteristic.
Value Type
DOMString
Default Value
Empty string ("")

instanceId

Description
This property stores the instance id of this characteristic.
Value Type
unsigned short
Default Value
0

value

Description
The cached value of this characteristic. This value can be updated via readValue() method or via characteristic notification or indication from the remote device.
Value Type
ArrayBuffer or null
Default Value
null pointer

properties

Description
A bit mask which describes how the characteristic value can be used.
Value Type
dictionary CharacteristicProperties
Default Value
0

writeType

Description
The type of write operation.
Value Type
dictionary CharacteristicWriteType
Default Value
0

Methods

readValue()

Description
Read the characteristic value from the remote device. The cached value property will also be updated after retrieving the value.
Return
A Promise to indicate whether the operation is resolved or rejected. The Promise is resolved along with the value retrieved from the remote device.

writeValue(ArrayBuffer value)

Description
Write the characteristic value to the remote device.
Parameter
value
Desired value to be written to the remote device.
Return
A Promise to indicate whether the operation is resolved or rejected. The Promise is resolved along with the characteristic value after this write operation.

startNotifications()

Description
Register notification/indication of this characteristic.
Return
A Promise to indicate whether the operation is resolved or rejected. The Promise is rejected if there is no Client Characteristic Configuration descriptor (CCCD) for this characteristic.

stopNotifications()

Description
Unregister notification/indication of this characteristic.
Return
A Promise to indicate whether the operation is resolved or rejected. The Promise is rejected if there is no Client Characteristic Configuration descriptor (CCCD) for this characteristic.
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