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    cordova-plugin-ble-central
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    1.6.1 • Public • Published

    Bluetooth Low Energy (BLE) Central Plugin for Apache Cordova

    npm version

    This plugin enables communication between a phone and Bluetooth Low Energy (BLE) peripherals.

    The plugin provides a simple JavaScript API for iOS and Android.

    • Scan for peripherals
    • Connect to a peripheral
    • Read the value of a characteristic
    • Write new value to a characteristic
    • Get notified when characteristic's value changes
    • Transfer data via L2CAP channels

    Advertising information is returned when scanning for peripherals. Service, characteristic, and property info is returned when connecting to a peripheral. All access is via service and characteristic UUIDs. The plugin manages handles internally.

    Simultaneous connections to multiple peripherals are supported.

    This plugin isn't intended for scanning beacons. Try cordova-plugin-ibeacon for iBeacons.
    If you want to create Bluetooth devices, try cordova-plugin-ble-peripheral.

    See the examples for ideas on how this plugin can be used.

    Supported Platforms

    • iOS
    • Android (likely supports 6+, but 8.1 or greater recommended)
    • Browser (where navigator.bluetooth is supported)

    Installing

    Cordova

    $ cordova plugin add cordova-plugin-ble-central
    

    It's recommended to always use the latest cordova and cordova platform packages in order to enusre correct function. This plugin generally best supports the following platforms and version ranges:

    cordova cordova-ios cordova-android cordova-browser
    10+ 6.2.0+ 10.0+ not tested

    iOS

    For iOS, apps will crash unless they include usage description keys for the types of data they access. Applications targeting iOS 13 and later, define NSBluetoothAlwaysUsageDescription to tell the user why the application needs Bluetooth. For apps with a deployment target earlier than iOS 13, add NSBluetoothPeripheralUsageDescription. Both of these keys can be set when installing the plugin by passing the BLUETOOTH_USAGE_DESCRIPTION variable.

    $ cordova plugin add cordova-plugin-ble-central --variable BLUETOOTH_USAGE_DESCRIPTION="Your description here"
    

    See Apple's documentation about Protected Resources for more details. If your app needs other permissions like location, try the cordova-custom-config plugin.

    It is possible to delay the initialization of the plugin on iOS. Normally the Bluetooth permission dialog is shown when the app loads for the first time. Delaying the initialization of the plugin shows the permission dialog the first time the Bluetooth API is called. Set IOS_INIT_ON_LOAD to false when installing.

    --variable IOS_INIT_ON_LOAD=false
    

    If background scanning and operation is required, the iOS restore state should be enabled:

    --variable BLUETOOTH_RESTORE_STATE=true
    

    For more information about background operation, see Background Scanning and Notifications on iOS.

    Android

    If you are having Android permissions conflicts with other plugins, try using the slim variant of the plugin instead with cordova plugin add cordova-plugin-ble-central@slim. This variant excludes all Android permissions, leaving it to the developer to ensure the right entries are added manually to the AndroidManifest.xml (see below for an example).

    To include the default set of permissions the plugin installs on Android SDK v31+, add the following snippet in your config.xml file, in the <platform name="android"> section:

        <config-file target="AndroidManifest.xml" parent="/manifest">
            <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" android:maxSdkVersion="28" />
            <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" android:maxSdkVersion="30" />
            <uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30" />
            <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" android:maxSdkVersion="30" />
            <uses-permission android:name="android.permission.BLUETOOTH_SCAN" android:usesPermissionFlags="neverForLocation" />
            <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
        </config-file>
    

    If your app targets Android 10 (API level 29) or higher, you may need the ACCESS_BACKGROUND_LOCATION permission on Android 10 & Android 11 in order for scanning to function when your app is not visible. To enable this permission and feature, set ACCESS_BACKGROUND_LOCATION to true when installing:

    --variable ACCESS_BACKGROUND_LOCATION=true
    

    For the best understanding about which permissions are needed for which combinations of target SDK version & OS version, see Android Bluetooth permissions

    API

    Methods

    scan

    Scan and discover BLE peripherals.

    ble.scan(services, seconds, success, failure);
    

    Description

    Function scan scans for BLE devices. The success callback is called each time a peripheral is discovered. Scanning automatically stops after the specified number of seconds.

    {
        "name": "TI SensorTag",
        "id": "BD922605-1B07-4D55-8D09-B66653E51BBA",
        "rssi": -79,
        "advertising": /* ArrayBuffer or map */
    }
    

    Advertising information format varies depending on your platform. See Advertising Data for more information.

    Location Permission Notes

    With Android SDK >= 23 (6.0), additional permissions are required for Bluetooth low energy scanning. The location permission ACCESS_COARSE_LOCATION is required because Bluetooth beacons can be used to determine a user's location. If necessary, the plugin will prompt the user to allow the app to access to device's location. If the user denies permission, the scan failure callback will receive the error "Location permission not granted".

    Location Services must be enabled for Bluetooth scanning. If location services are disabled, the failure callback will receive the error "Location services are disabled". If you want to manage location permission and screens, try the cordova-diagonostic-plugin or the Ionic Native Diagnostic plugin.

    Parameters

    • services: List of services to discover, or [] to find all devices
    • seconds: Number of seconds to run discovery
    • success: Success callback function that is invoked which each discovered device.
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    ble.scan([], 5, function(device) {
        console.log(JSON.stringify(device));
    }, failure);
    

    startScan

    Scan and discover BLE peripherals.

    ble.startScan(services, success, failure);
    

    Description

    Function startScan scans for BLE devices. The success callback is called each time a peripheral is discovered. Scanning will continue until stopScan is called.

    {
        "name": "TI SensorTag",
        "id": "BD922605-1B07-4D55-8D09-B66653E51BBA",
        "rssi": -79,
        "advertising": /* ArrayBuffer or map */
    }
    

    Advertising information format varies depending on your platform. See Advertising Data for more information.

    See the location permission notes above for information about Location Services in Android SDK >= 23.

    Parameters

    • services: List of services to discover, or [] to find all devices
    • success: Success callback function that is invoked which each discovered device.
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    ble.startScan([], function(device) {
        console.log(JSON.stringify(device));
    }, failure);
    
    setTimeout(ble.stopScan,
        5000,
        function() { console.log("Scan complete"); },
        function() { console.log("stopScan failed"); }
    );
    

    startScanWithOptions

    Scan and discover BLE peripherals, specifying scan options.

    ble.startScanWithOptions(services, options, success, failure);
    

    Description

    Function startScanWithOptions scans for BLE devices. It operates similarly to the startScan function, but allows you to specify extra options (like allowing duplicate device reports). The success callback is called each time a peripheral is discovered. Scanning will continue until stopScan is called.

    {
        "name": "TI SensorTag",
        "id": "BD922605-1B07-4D55-8D09-B66653E51BBA",
        "rssi": -79,
        "advertising": /* ArrayBuffer or map */
    }
    

    Advertising information format varies depending on your platform. See Advertising Data for more information.

    See the location permission notes above for information about Location Services in Android SDK >= 23.

    Parameters

    • services: List of services to discover, or [] to find all devices
    • options: an object specifying a set of name-value pairs. The currently acceptable options are:
      • reportDuplicates: true if duplicate devices should be reported, false (default) if devices should only be reported once. [optional]
      • scanMode: String defines setScanMode() argument on Android.
        Can be one of: lowPower | balanced | lowLatency | opportunistic
      • callbackType: String defines setCallbackType() argument on Android.
        Can be one of: all | first | lost
      • matchMode: String defines setMatchMode() argument on Android.
        Can be one of: aggressive | sticky
      • numOfMatches: String defines setNumOfMatches() argument on Android.
        Can be one of: one | few | max
      • phy: String for setPhy() on Android.
        Can be one of: 1m | coded | all
      • legacy: true or false to control filtering bluetooth spec.pre-4.2 advertisements on Android.
      • reportDelay: Milliseconds for setReportDelay() on Android. 0 to be notified of results immediately. Values > 0 causes the scan results to be queued up and delivered after the requested delay or when the internal buffers fill up.
    • success: Success callback function that is invoked which each discovered device.
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    ble.startScanWithOptions([],
        { reportDuplicates: true }
        function(device) {
            console.log(JSON.stringify(device));
        },
        failure);
    
    setTimeout(ble.stopScan,
        5000,
        function() { console.log("Scan complete"); },
        function() { console.log("stopScan failed"); }
    );
    

    stopScan

    Stop scanning for BLE peripherals.

    ble.stopScan(success, failure);
    // Or using await with promises
    await ble.withPromises.stopScan()
    

    Description

    Function stopScan stops scanning for BLE devices.

    Parameters

    • success: Success callback function, invoked when scanning is stopped. [optional]
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    ble.startScan([], function(device) {
        console.log(JSON.stringify(device));
    }, failure);
    
    setTimeout(ble.stopScan,
        5000,
        function() { console.log("Scan complete"); },
        function() { console.log("stopScan failed"); }
    );
    
    /* Alternate syntax
    setTimeout(function() {
        ble.stopScan(
            function() { console.log("Scan complete"); },
            function() { console.log("stopScan failed"); }
        );
    }, 5000);
    */
    

    setPin

    Set device pin

    ble.setPin(pin, [success], [failure]);
    // Or using await with promises
    await ble.withPromises.setPin(pin)
    

    Description

    Function setPin sets the pin when device requires it.

    Parameters

    • pin: Pin of the device as a string
    • success: Success callback function that is invoked when the function is invoked. [optional]
    • failure: Error callback function, invoked when error occurs. [optional]

    connect

    Connect to a peripheral.

    ble.connect(device_id, connectCallback, disconnectCallback);
    

    Description

    Function connect connects to a BLE peripheral. The callback is long running. The connect callback will be called when the connection is successful. Service and characteristic info will be passed to the connect callback in the peripheral object.

    The disconnect callback is called if the connection fails, or later if the peripheral disconnects. When possible, a peripheral object is passed to the failure callback. The disconnect callback is only called when the peripheral initates the disconnection. The disconnect callback is not called when the application calls ble.disconnect. The disconnect callback is how your app knows the peripheral inintiated a disconnect.

    Scanning before connecting

    Android can connect to peripherals using MAC address without scanning. If the MAC address is not found the connection will time out.

    For iOS, the plugin needs to know about any device UUID before calling connect. You can do this by calling ble.scan, ble.startScan, ble.connectedPeripheralsWithServices, or ble.peripheralsWithIdentifiers so the plugin has a list of available peripherals.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • connectCallback: Connect callback function that is invoked when the connection is successful.
    • disconnectCallback: Disconnect callback function, invoked when the peripheral disconnects or an error occurs.

    autoConnect

    Establish an automatic connection to a peripheral.

    ble.autoConnect(device_id, connectCallback, disconnectCallback);
    

    Description

    Automatically connect to a device when it is in range of the phone. When the device connects, the connect callback is called with a peripheral object. The call to autoConnect will not time out. It will wait forever until the device is in range. When the peripheral disconnects, the disconnect callback is called with a peripheral object.

    Calling ble.disconnect will stop the automatic reconnection.

    Both the connect and disconnect callbacks can be called many times as the device connects and disconnects. Do not wrap this function in a Promise or Observable.

    On iOS, background notifications on ios must be enabled if you want to run in the background. On Android, this relies on the autoConnect argument of BluetoothDevice.connectGatt(). Not all Android devices implement this feature correctly.

    See notes about scanning before connecting

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • connectCallback: Connect callback function that is invoked when the connection is successful.
    • disconnectCallback: Disconnect callback function, invoked when the peripheral disconnects or an error occurs.

    disconnect

    Disconnect.

    ble.disconnect(device_id, [success], [failure]);
    // Or using await with promises
    await ble.withPromises.disconnect(device_id)
    

    Description

    Function disconnect disconnects the selected device.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • success: Success callback function that is invoked when the connection is successful. [optional]
    • failure: Error callback function, invoked when error occurs. [optional]

    requestMtu

    requestMtu

    ble.requestMtu(device_id, mtu, [success], [failure]);
    

    Description

    This function may be used to request (on Android) a larger MTU size to be able to send more data at once. This can be useful when performing a write request operation (write without response), the data sent is truncated to the MTU size. The resulting MTU size is sent to the success callback. The requested and resulting MTU sizes are not necessarily equal.

    Supported Platforms

    • Android

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • mtu: MTU size
    • success: Success callback function that is invoked when the MTU size request is successful. The resulting MTU size is passed as an integer.
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    ble.requestMtu(device_id, new_mtu,
        function(mtu){
            alert("MTU set to: " + mtu);
        },
        function(failure){
            alert("Failed to request MTU.");
        }
    );
    

    requestConnectionPriority

    requestConnectionPriority

    ble.requestConnectionPriority(device_id, priority, [success], [failure]);
    // Or using await with promises
    await ble.withPromises.requestConnectionPriority(device_id, priority)
    

    Description

    When Connecting to a peripheral android can request for the connection priority for better communication. See BluetoothGatt#requestConnectionPriority for technical details

    Connection priority can be one of:

    Supported Platforms

    • Android

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • priority: "high", "balanced" or "low"
    • success: Success callback function that is invoked when the connection is successful. [optional]
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    ble.requestConnectionPriority(device_id, "high",
        function() {
            alert("success");
        },
        function(failure){
            alert("Failed to request connection priority: " + failure);
        }
    );
    

    refreshDeviceCache

    refreshDeviceCache

    ble.refreshDeviceCache(deviceId, timeoutMillis,  [success], [failure]);
    

    Description

    Some poorly behaved devices show old cached services and characteristics info. (Usually because they don't implement Service Changed 0x2a05 on Generic Attribute Service 0x1801 and the central doesn't know the data needs to be refreshed.) This method might help.

    NOTE Since this uses an undocumented API it's not guaranteed to work.

    Supported Platforms

    • Android

    Parameters

    • deviceId: UUID or MAC address of the peripheral
    • timeoutMillis: timeout in milliseconds after refresh before discovering services
    • success: Success callback function invoked with the refreshed peripheral. [optional]
    • failure: Error callback function, invoked when an error occurs. [optional]

    read

    Reads the value of a characteristic.

    ble.read(device_id, service_uuid, characteristic_uuid, success, failure);
    // Or using await with promises
    const data = await ble.withPromises.read(device_id, service_uuid, characteristic_uuid)
    

    Description

    Function read reads the value of the characteristic.

    Raw data is passed from native code to the callback as an ArrayBuffer.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • service_uuid: UUID of the BLE service
    • characteristic_uuid: UUID of the BLE characteristic
    • success: Success callback function that is invoked when the connection is successful. [optional]
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    Retrieves an ArrayBuffer when reading data.

    // read data from a characteristic, do something with output data
    ble.read(device_id, service_uuid, characteristic_uuid,
        function(data){
            console.log("Hooray we have data"+JSON.stringify(data));
            alert("Successfully read data from device."+JSON.stringify(data));
        },
        function(failure){
            alert("Failed to read characteristic from device.");
        }
    );
    

    write

    Writes data to a characteristic.

    ble.write(device_id, service_uuid, characteristic_uuid, data, success, failure);
    // Or using await with promises
    await ble.withPromises.write(device_id, service_uuid, characteristic_uuid, data)
    

    Description

    Function write writes data to a characteristic.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • service_uuid: UUID of the BLE service
    • characteristic_uuid: UUID of the BLE characteristic
    • data: binary data, use an ArrayBuffer
    • success: Success callback function that is invoked when the connection is successful. [optional]
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    Use an ArrayBuffer when writing data.

    // send 1 byte to switch a light on
    var data = new Uint8Array(1);
    data[0] = 1;
    ble.write(device_id, "FF10", "FF11", data.buffer, success, failure);
    
    // send a 3 byte value with RGB color
    var data = new Uint8Array(3);
    data[0] = 0xFF; // red
    data[1] = 0x00; // green
    data[2] = 0xFF; // blue
    ble.write(device_id, "ccc0", "ccc1", data.buffer, success, failure);
    
    // send a 32 bit integer
    var data = new Uint32Array(1);
    data[0] = counterInput.value;
    ble.write(device_id, SERVICE, CHARACTERISTIC, data.buffer, success, failure);
    

    writeWithoutResponse

    Writes data to a characteristic without confirmation from the peripheral.

    ble.writeWithoutResponse(device_id, service_uuid, characteristic_uuid, data, success, failure);
    // Or using await with promises
    await ble.withPromises.writeWithoutResponse(device_id, service_uuid, characteristic_uuid, data)
    

    Description

    Function writeWithoutResponse writes data to a characteristic without a response from the peripheral. You are not notified if the write fails in the BLE stack. The success callback is be called when the characteristic is written.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • service_uuid: UUID of the BLE service
    • characteristic_uuid: UUID of the BLE characteristic
    • data: binary data, use an ArrayBuffer
    • success: Success callback function that is invoked when the connection is successful. [optional]
    • failure: Error callback function, invoked when error occurs. [optional]

    startNotification

    Register to be notified when the value of a characteristic changes.

    ble.startNotification(device_id, service_uuid, characteristic_uuid, success, failure);
    // Or using await with promises
    // Note, initial promise resolves or rejects depending on whether the subscribe was successful
    await ble.withPromises.startNotification(device_id, success, failure)
    

    Description

    Function startNotification registers a callback that is called every time the value of a characteristic changes. This method handles both notifications and indications. The success callback is called multiple times.

    Raw data is passed from native code to the success callback as an ArrayBuffer.

    See Background Notifications on iOS

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • service_uuid: UUID of the BLE service
    • characteristic_uuid: UUID of the BLE characteristic
    • success: Success callback function invoked every time a notification occurs
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    var onData = function(buffer) {
        // Decode the ArrayBuffer into a typed Array based on the data you expect
        var data = new Uint8Array(buffer);
        alert("Button state changed to " + data[0]);
    }
    
    ble.startNotification(device_id, "FFE0", "FFE1", onData, failure);
    

    stopNotification

    Stop being notified when the value of a characteristic changes.

    ble.stopNotification(device_id, service_uuid, characteristic_uuid, success, failure);
    // Or using await with promises
    await ble.withPromises.stopNotification(device_id)
    

    Description

    Function stopNotification stops a previously registered notification callback.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • service_uuid: UUID of the BLE service
    • characteristic_uuid: UUID of the BLE characteristic
    • success: Success callback function that is invoked when the notification is removed. [optional]
    • failure: Error callback function, invoked when error occurs. [optional]

    isConnected

    Reports the connection status.

    ble.isConnected(device_id, success, failure);
    // Or using await with promises
    await ble.withPromises.isConnected(device_id)
    

    Description

    Function isConnected calls the success callback when the peripheral is connected and the failure callback when not connected.

    NOTE that for many apps isConnected is unncessary. The app can track the connected state. Ater calling connect the app is connected when the success callback function is called. If the device disconnects at any point in the future, the failure callback of connect will be called.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • success: Success callback function that is invoked with a boolean for connected status.
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    ble.isConnected(
        'FFCA0B09-CB1D-4DC0-A1EF-31AFD3EDFB53',
        function() {
            console.log("Peripheral is connected");
        },
        function() {
            console.log("Peripheral is *not* connected");
        }
    );
    

    isEnabled

    Reports if bluetooth is enabled.

    ble.isEnabled(success, failure);
    

    Description

    Function isEnabled calls the success callback when Bluetooth is enabled and the failure callback when Bluetooth is not enabled.

    Parameters

    • success: Success callback function, invoked when Bluetooth is enabled.
    • failure: Error callback function, invoked when Bluetooth is disabled.

    Quick Example

    ble.isEnabled(
        function() {
            console.log("Bluetooth is enabled");
        },
        function() {
            console.log("Bluetooth is *not* enabled");
        }
    );
    

    isLocationEnabled

    Reports if location services are enabled.

    ble.isLocationEnabled(success, failure);
    

    Description

    Function isLocationEnabled calls the success callback when location services are enabled and the failure callback when location services are not enabled. On some devices, location services must be enabled in order to scan for peripherals.

    Supported Platforms

    • Android

    Parameters

    • success: Success callback function, invoked when location services are enabled.
    • failure: Error callback function, invoked when location services are disabled.

    Quick Example

    ble.isLocationEnabled(
        function() {
            console.log("location services are enabled");
        },
        function() {
            console.log("location services are *not* enabled");
        }
    );
    

    startLocationStateNotifications

    Registers to be notified when Location service state changes on the device.

    ble.startLocationStateNotifications(success, failure);
    // Or using await with promises
    // Note, initial promise resolves or rejects depending on whether the subscribe was successful
    await ble.withPromises.startLocationStateNotifications(success, failure)
    

    Description

    Function startLocationStateNotifications calls the success callback when the Location service is enabled or disabled on the device.

    Supported Platforms

    • Android

    Parameters

    • success: Success callback function that is invoked with a boolean for the Location state.
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    ble.startLocationStateNotifications(
        function(enabled) {
            console.log("Location is " + enabled);
        }
    );
    

    stopLocationStateNotifications

    Stops state notifications.

    ble.stopLocationStateNotifications(success, failure);
    // Or using await with promises
    await ble.withPromises.stopLocationStateNotifications()
    

    Description

    Function stopLocationStateNotifications calls the success callback when Location state notifications have been stopped.

    Supported Platforms

    • Android

    startStateNotifications

    Registers to be notified when Bluetooth state changes on the device.

    ble.startStateNotifications(success, failure);
    // Or using await with promises
    // Note, initial promise resolves or rejects depending on whether the subscribe was successful
    await ble.withPromises.startStateNotifications(success, failure)
    

    Description

    Function startStateNotifications calls the success callback when the Bluetooth is enabled or disabled on the device.

    States

    • "on"
    • "off"
    • "turningOn" (Android Only)
    • "turningOff" (Android Only)
    • "unknown" (iOS Only)
    • "resetting" (iOS Only)
    • "unsupported" (iOS Only)
    • "unauthorized" (iOS Only)

    Supported Platforms

    • Android
    • iOS

    Parameters

    • success: Success callback function that is invoked with a string for the Bluetooth state.
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    ble.startStateNotifications(
        function(state) {
            console.log("Bluetooth is " + state);
        }
    );
    

    stopStateNotifications

    Stops state notifications.

    ble.stopStateNotifications(success, failure);
    // Or using await with promises
    await ble.withPromises.stopStateNotifications()
    

    Description

    Function stopStateNotifications calls the success callback when Bluetooth state notifications have been stopped.

    Supported Platforms

    • Android
    • iOS

    showBluetoothSettings

    Show the Bluetooth settings on the device.

    ble.showBluetoothSettings(success, failure);
    // Or using await with promises
    await ble.withPromises.showBluetoothSettings()
    

    Description

    Function showBluetoothSettings opens the Bluetooth settings for the operating systems.

    showBluetoothSettings is not available on iOS. Plugins like cordova-diagonostic-plugin and the Ionic Native Diagnostic plugin have APIs to open Bluetooth and other settings, but will often get apps rejected by Apple.

    Supported Platforms

    • Android

    Parameters

    • success: Success callback function [optional]
    • failure: Error callback function, invoked when error occurs. [optional]

    Quick Example

    ble.showBluetoothSettings();
    

    enable

    Enable Bluetooth on the device.

    ble.enable(success, failure);
    // Or using await with promises
    ble.withPromises.enable();
    

    Description

    Function enable prompts the user to enable Bluetooth.

    enable is only supported on Android and does not work on iOS.

    If enable is called when Bluetooth is already enabled, the user will not prompted and the success callback will be invoked.

    Supported Platforms

    • Android

    Parameters

    • success: Success callback function, invoked if the user enabled Bluetooth.
    • failure: Error callback function, invoked if the user does not enabled Bluetooth.

    Quick Example

    ble.enable(
        function() {
            console.log("Bluetooth is enabled");
        },
        function() {
            console.log("The user did *not* enable Bluetooth");
        }
    );
    

    readRSSI

    Read the RSSI value on the device connection.

    ble.readRSSI(device_id, success, failure);
    

    Description

    Samples the RSSI value (a measure of signal strength) on the connection to a bluetooth device. Requires that you have established a connection before invoking (otherwise an error will be raised).

    Parameters

    • device_id: device identifier
    • success: Success callback function, invoked with the RSSI value (as an integer)
    • failure: Error callback function, invoked if there is no current connection or if there is an error reading the RSSI.

    Quick Example

    var rssiSample;
    ble.connect(device_id,
        function(device) {
            rssiSample = setInterval(function() {
                    ble.readRSSI(device_id, function(rssi) {
                            console.log('read RSSI',rssi,'with device', device_id);
                        }, function(err) {
                            console.error('unable to read RSSI',err);
                            clearInterval(rssiSample);
                            })
                }, 5000);
        },
        function(err) { console.error('error connecting to device')}
        );
    

    connectedPeripheralsWithServices

    Find the connected peripherals offering the listed service UUIDs.

    ble.connectedPeripheralsWithServices([service], success, failure);
    

    Description

    Retreives a list of the peripherals (containing any of the specified services) currently connected to the system. The peripheral list is sent to the success callback. This function wraps CBCentralManager.retrieveConnectedPeripheralsWithServices:

    Supported Platforms

    • iOS

    Parameters

    • services: List of services to discover
    • success: Success callback function, invoked with a list of peripheral objects
    • failure: Error callback function

    peripheralsWithIdentifiers

    Find the connected peripherals offering the listed peripheral UUIDs.

    ble.peripheralsWithIdentifiers([uuids], success, failure);
    

    Description

    Sends a list of known peripherals by their identifiers to the success callback. This function wraps CBCentralManager.retrievePeripheralsWithIdentifiers:

    Supported Platforms

    • iOS

    Parameters

    • identifiers: List of peripheral UUIDs
    • success: Success callback function, invoked with a list of peripheral objects
    • failure: Error callback function

    restoredBluetoothState

    Retrieve the CBManager restoration state (if applicable)

    ble.restoredBluetoothState(success, failure);
    // Or using await with promises
    await ble.withPromises.restoredBluetoothState();
    

    Description

    Use of this feature requires the BLUETOOTH_RESTORE_STATE variable to be set to true. For more information about background operation, see Background Scanning and Notifications on iOS.

    Retrives the state dictionary that iOS State Preservation and Restoration will supply when the application was launched by iOS.

    If the application has no state restored, this will return an empty object.

    Supported Platforms

    • iOS

    Parameters

    • success: Success callback function, invoked with the restored Bluetooth state (if any)
    • failure: Error callback function

    list

    Lists all peripherals discovered by the plugin due to scanning or connecting since app launch.

    ble.list(success, failure);
    // Or using await with promises
    await ble.withPromises.list();
    

    Description

    Sends a list of bonded low energy peripherals to the success callback.

    Supported Platforms

    • Android

    Parameters

    • success: Success callback function, invoked with a list of peripheral objects
    • failure: Error callback function

    bondedDevices

    Find the bonded devices.

    ble.bondedDevices(success, failure);
    // Or using await with promises
    await ble.withPromises.bondedDevices();
    

    Description

    Sends a list of bonded low energy peripherals to the success callback.

    Supported Platforms

    • Android

    Parameters

    • success: Success callback function, invoked with a list of peripheral objects
    • failure: Error callback function

    l2cap.open

    Open an L2CAP channel with a connected peripheral. The PSM is assigned by the peripheral, or possibly defined by the Bluetooth standard.

    ble.l2cap.open(device_id, psm, connectCallback, disconnectCallback);
    // Or using await with promises
    await ble.withPromises.l2cap.open(device_id, psm, disconnectCallback);
    

    Android supports additional arguments in the psm flag to select whether the L2CAP channel is insecure or secure (iOS does this automatically):

    ble.l2cap.open(device_id, { psm: psm, secureChannel: true }, connectCallback, disconnectCallback);
    // Or using await with promises
    await ble.withPromises.l2cap.open(device_id, { psm: psm, secureChannel: true }, disconnectCallback);
    

    Description

    An L2CAP channel is a duplex byte stream interface (similar to a network socket) that can be used for much more efficient binary data transfer. This is used in some streaming applications, such as the Bluetooth Object Transfer Service.

    The PSM (protocol/service multiplexer) is specified by the peripheral when it opens the channel. Some channels have predefined identifiers controlled by Bluetooth organisation. Apple has also outlined a generic design for PSM exchange. To advertise an L2CAP channel on a specific service, a characteristic with the UUID "ABDD3056-28FA-441D-A470-55A75A52553A" is added to that service, and updated by the peripheral when the L2CAP channel is opened.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • psm or options: Protocol/service multiplexer, specified by the peripheral when the channel was opened. Can be an object which includes a psm key, with an optional secureChannel boolean setting to control whether the channel is encrypted or not (Android-only)
    • connectCallback: Connect callback function, invoked when an L2CAP connection is successfully opened
    • disconnectCallback: Disconnect callback function, invoked when the L2CAP stream closes or an error occurs.

    Supported Platforms

    • iOS
    • Android (>= 10)

    l2cap.close

    Close an L2CAP channel.

    ble.l2cap.close(device_id, psm, success, failure);
    // Or using await with promises
    await ble.withPromises.l2cap.close(device_id, psm);
    

    Description

    Closes an open L2CAP channel with the selected device. All pending reads and writes are aborted.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • psm: Protocol/service multiplexer, specified by the peripheral when the channel was opened
    • success: Success callback function that is invoked when the stream is closed successfully. [optional]
    • failure: Error callback function, invoked when error occurs. [optional]

    Supported Platforms

    • iOS
    • Android (>= 10)

    l2cap.receiveData

    Receive data from an L2CAP channel.

    ble.l2cap.receiveData(device_id, psm, dataCallback);
    

    Description

    Sets the function to be called whenever bytes are received on the L2CAP channel. This function will be used as long as the L2CAP connection remains open.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • psm: Protocol/service multiplexer, specified by the peripheral when the channel was opened
    • dataCallback: Data processing function that is invoked when bytes are received from the peripheral

    Supported Platforms

    • iOS
    • Android (>= 10)

    l2cap.write

    Write data to an L2CAP channel.

    ble.l2cap.write(device_id, psm, data, success, failure);
    // Or using await with promises
    await ble.withPromises.l2cap.write(device_id, psm, data);
    

    Description

    Writes all data to an open L2CAP channel. If the data exceeds the available space in the transmit buffer, the data will be automatically sent in chunks as space becomes available. The success callback is called only once after all the supplied bytes have been written to the transmit stream.

    Parameters

    • device_id: UUID or MAC address of the peripheral
    • psm: Protocol/service multiplexer, specified by the peripheral when the channel was opened
    • data: Data to write to the stream
    • success: Success callback function that is invoked after all bytes have been written to the stream [optional]
    • failure: Error callback function, invoked when error occurs [optional]

    Supported Platforms

    • iOS
    • Android (>= 10)

    Peripheral Data

    Peripheral Data is passed to the success callback when scanning and connecting. Limited data is passed when scanning.

    {
        "name": "Battery Demo",
        "id": "20:FF:D0:FF:D1:C0",
        "advertising": [2,1,6,3,3,15,24,8,9,66,97,116,116,101,114,121],
        "rssi": -55
    }
    

    After connecting, the peripheral object also includes service, characteristic and descriptor information.

    {
        "name": "Battery Demo",
        "id": "20:FF:D0:FF:D1:C0",
        "advertising": [2,1,6,3,3,15,24,8,9,66,97,116,116,101,114,121],
        "rssi": -55,
        "services": [
            "1800",
            "1801",
            "180f"
        ],
        "characteristics": [
            {
                "service": "1800",
                "characteristic": "2a00",
                "properties": [
                    "Read"
                ]
            },
            {
                "service": "1800",
                "characteristic": "2a01",
                "properties": [
                    "Read"
                ]
            },
            {
                "service": "1801",
                "characteristic": "2a05",
                "properties": [
                    "Read"
                ]
            },
            {
                "service": "180f",
                "characteristic": "2a19",
                "properties": [
                    "Read"
                ],
                "descriptors": [
                    {
                        "uuid": "2901"
                    },
                    {
                        "uuid": "2904"
                    }
                ]
            }
        ]
    }
    

    Advertising Data

    Bluetooth advertising data is returned in when scanning for devices. The format varies depending on your platform. On Android advertising data will be the raw advertising bytes. iOS does not allow access to raw advertising data, so a dictionary of data is returned.

    The advertising information for both Android and iOS appears to be a combination of advertising data and scan response data.

    Ideally a common format (map or array) would be returned for both platforms in future versions. If you have ideas, please contact me.

    Android

    {
        "name": "demo",
        "id": "00:1A:7D:DA:71:13",
        "advertising": ArrayBuffer,
        "rssi": -37
    }
    

    Convert the advertising info to a Uint8Array for processing. var adData = new Uint8Array(peripheral.advertising). You application is responsible for parsing all the information out of the advertising ArrayBuffer using the GAP type constants. For example to get the service data from the advertising info, I parse the advertising info into a map and then get the service data to retrieve a characteristic value that is being broadcast.

    iOS

    Note that iOS uses the string value of the constants for the Advertisement Data Retrieval Keys. This will likely change in the future.

    {
        "name": "demo"
        "id": "15B4F1C5-C9C0-4441-BD9F-1A7ED8F7A365",
        "advertising": {
            "kCBAdvDataLocalName": "demo",
            "kCBAdvDataManufacturerData": {}, // arraybuffer data not shown
            "kCBAdvDataServiceUUIDs": [
                "721b"
            ],
            "kCBAdvDataIsConnectable": true,
            "kCBAdvDataServiceData": {
                "BBB0": {}   // arraybuffer data not shown
            },
        },
        "rssi": -61
    }
    

    Some of the values such as kCBAdvDataManufacturerData are ArrayBuffers. The data won't print out, but you can convert it to bytes using new Uint8Array(peripheral.advertisting.kCBAdvDataManufacturerData). Your application is responsible for parsing and decoding any binary data such as kCBAdvDataManufacturerData or kCBAdvDataServiceData.

    function onDiscoverDevice(device) {
        // log the device as JSON
        console.log('Found Device', JSON.stringify(device, null, 2));
    
        // on iOS, print the manufacturer data if it exists
        if (device.advertising && device.advertising.kCBAdvDataManufacturerData) {
            const mfgData = new Uint8Array(device.advertising.kCBAdvDataManufacturerData);
            console.log('Manufacturer Data is', mfgData);
        }
    
    }
    
    ble.scan([], 5, onDiscoverDevice, onError);
    

    Browser

    Chrome

    Enable: chrome://flags/#enable-experimental-web-platform-features and chrome://flags/#enable-web-bluetooth-new-permissions-backend

    Scan must be initiated from a user action (click, touch, etc).

    Typed Arrays

    This plugin uses typed Arrays or ArrayBuffers for sending and receiving data.

    This means that you need convert your data to ArrayBuffers before sending and from ArrayBuffers when receiving.

    // ASCII only
    function stringToBytes(string) {
       var array = new Uint8Array(string.length);
       for (var i = 0, l = string.length; i < l; i++) {
           array[i] = string.charCodeAt(i);
        }
        return array.buffer;
    }
    
    // ASCII only
    function bytesToString(buffer) {
        return String.fromCharCode.apply(null, new Uint8Array(buffer));
    }
    

    You can read more about typed arrays in these articles on MDN and HTML5 Rocks.

    UUIDs

    UUIDs are always strings and not numbers. Some 16-bit UUIDs, such as '2220' look like integers, but they're not. (The integer 2220 is 0x8AC in hex.) This isn't a problem with 128 bit UUIDs since they look like strings 82b9e6e1-593a-456f-be9b-9215160ebcac. All 16-bit UUIDs should also be passed to methods as strings.

    Background Scanning and Notifications on iOS

    Android applications will continue to receive notification while the application is in the background.

    iOS applications need additional configuration to allow Bluetooth to run in the background.

    Add a new section to config.xml

    <platform name="ios">
        <config-file parent="UIBackgroundModes" target="*-Info.plist">
            <array>
                <string>bluetooth-central</string>
            </array>
        </config-file>
    </platform>
    

    See ble-background example project for more details.

    Additionally, iOS state restoration should be enabled if long-running scans or connects should be restarted after the phone is rebooted or the app is suspended by iOS. See iOS restore state for the details and limitations of this feature.

    To activate iOS state restoration, set the BLUETOOTH_RESTORE_STATE to true when adding the plugin to the project:

    --variable BLUETOOTH_RESTORE_STATE=true
    

    By default, the app id (otherwise known as the bundle identifier) will be used as the iOS restore identifier key. This can be overridden by setting the variable to the desired key directly. For example:

    --variable BLUETOOTH_RESTORE_STATE=my.custom.restoration.identifier.key
    

    It's important to note that iOS will not automatically relaunch an application under some conditions. For a detailed list of these conditions, see the iOS Technical QA on the subject.

    Testing the Plugin

    Tests require the Cordova Plugin Test Framework

    Create a new project

    git clone https://github.com/don/cordova-plugin-ble-central
    cordova create ble-test com.example.ble.test BLETest
    cd ble-test
    cordova platform add android
    cordova plugin add ../cordova-plugin-ble-central
    cordova plugin add ../cordova-plugin-ble-central/tests
    cordova plugin add cordova-plugin-test-framework
    

    Change the start page in config.xml

    <content src="cdvtests/index.html" />
    

    Run the app on your phone

    cordova run android --device
    

    Release process

    Pre-release

    1. npm version prepatch --preid=alpha
    2. Align plugin.xml version with npm version
    3. npm publish --tag alpha --registry=https://registry.npmjs.org

    Release

    1. npm version patch
    2. Align plugin.xml version with npm version
    3. Update release notes
    4. npm publish --registry=https://registry.npmjs.org

    Release (lean)

    1. git merge master
    2. Align package.json and plugin.xml versions
    3. npm publish --tag lean --registry=https://registry.npmjs.org

    Nordic DFU

    If you need Nordic DFU capability, Tomáš Bedřich has a fork of this plugin that adds an updateFirmware() method that allows users to upgrade nRF5x based chips over the air. https://github.com/fxe-gear/cordova-plugin-ble-central

    License

    Apache 2.0

    Feedback

    Try the code. If you find an problem or missing feature, file an issue or create a pull request.

    Other Bluetooth Plugins

    Install

    npm i cordova-plugin-ble-central

    DownloadsWeekly Downloads

    2,005

    Version

    1.6.1

    License

    Apache-2.0

    Unpacked Size

    432 kB

    Total Files

    85

    Last publish

    Collaborators

    • don
    • peitschie