QBluetoothServiceDiscoveryAgent

The QBluetoothServiceDiscoveryAgent class enables you to query for Bluetooth services. More…

Inheritance diagram of PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent

Synopsis

Functions

Slots

  • def clear ()

  • def start ([mode=QBluetoothServiceDiscoveryAgent.DiscoveryMode.MinimalDiscovery])

  • def stop ()

Signals

Detailed Description

The discovery process relies on the Bluetooth Service Discovery Process (SDP). The following steps are required to query the services provided by all contactable Bluetooth devices:

def startServiceDiscovery(self):

    # Create a discovery agent and connect to its signals
    discoveryAgent = QBluetoothServiceDiscoveryAgent(self)
    connect(discoveryAgent, SIGNAL(serviceDiscovered(QBluetoothServiceInfo)),
            self, SLOT(serviceDiscovered(QBluetoothServiceInfo)))
    # Start a discovery
    discoveryAgent.start()
    #...

# In your local slot, read information about the found devices
def serviceDiscovered(self, service):

    print("Found service:", service.serviceName())
             << '(' << service.device().address().toString() << ')'

By default a minimal service discovery is performed. In this mode, the returned QBluetoothServiceInfo objects are guaranteed to contain only device and service UUID information. Depending on platform and device capabilities, other service information may also be available. The minimal service discovery mode relies on cached SDP data of the platform. Therefore it is possible that this discovery does not find a device although it is physically available. In such cases a full discovery must be performed to force an update of the platform cache. However for most use cases a minimal discovery is adequate as it is much quicker and other classes which require up-to-date information such as connectToService() will perform additional discovery if required. If the full service information is required, pass FullDiscovery as the discoveryMode parameter to start() .

This class may internally utilize QBluetoothDeviceDiscoveryAgent to find unknown devices.

The service discovery may find Bluetooth Low Energy services too if the target device is a combination of a classic and Low Energy device. Those devices are required to advertise their Low Energy services via SDP. If the target device only supports Bluetooth Low Energy services, it is likely to not advertise them via SDP. The QLowEnergyController class should be utilized to perform the service discovery on Low Energy devices.

On iOS, this class cannot be used because the platform does not expose an API which may permit access to QBluetoothServiceDiscoveryAgent related features.

class PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent([parent=None])

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent(deviceAdapter[, parent=None])

Parameters

Constructs a new QBluetoothServiceDiscoveryAgent with parent. The search is performed via the local default Bluetooth adapter.

Constructs a new QBluetoothServiceDiscoveryAgent for deviceAdapter and with parent.

It uses deviceAdapter for the service search. If deviceAdapter is default constructed the resulting QBluetoothServiceDiscoveryAgent object will use the local default Bluetooth adapter.

If a deviceAdapter is specified that is not a local adapter error() will be set to InvalidBluetoothAdapterError . Therefore it is recommended to test the error flag immediately after using this constructor.

Note

On WinRT the passed adapter address will be ignored.

Note

On Android passing any deviceAdapter address is meaningless as Android 6.0 or later does not publish the local Bluetooth address anymore. Subsequently, the passed adapter address can never be matched against the local adapter address. Therefore the subsequent call to start() will always trigger InvalidBluetoothAdapterError .

See also

error()

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.Error

This enum describes errors that can occur during service discovery.

Constant

Description

QBluetoothServiceDiscoveryAgent.NoError

No error has occurred.

QBluetoothServiceDiscoveryAgent.PoweredOffError

The Bluetooth adaptor is powered off, power it on before doing discovery.

QBluetoothServiceDiscoveryAgent.InputOutputError

Writing or reading from the device resulted in an error.

QBluetoothServiceDiscoveryAgent.InvalidBluetoothAdapterError

The passed local adapter address does not match the physical adapter address of any local Bluetooth device. This value was introduced by Qt 5.3.

QBluetoothServiceDiscoveryAgent.UnknownError

An unknown error has occurred.
PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.DiscoveryMode

This enum describes the service discovery mode.

Constant

Description

QBluetoothServiceDiscoveryAgent.MinimalDiscovery

Performs a minimal service discovery. The QBluetoothServiceInfo objects returned may be incomplete and are only guaranteed to contain device and service UUID information. Since a minimal discovery relies on cached SDP data it may not find a physically existing device until a FullDiscovery is performed.

QBluetoothServiceDiscoveryAgent.FullDiscovery

Performs a full service discovery.
PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.canceled()
PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.clear()

Clears the results of previous service discoveries and resets uuidFilter() . This function does nothing during an ongoing service discovery (see isActive() ).

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.discoveredServices()
Return type

Returns the list of all discovered services.

This list of services accumulates newly discovered services from multiple calls to start() . Unless clear() is called the list cannot decrease in size. This implies that if a remote Bluetooth device moves out of range in between two subsequent calls to start() the list may contain stale entries.

Note

The list of services should always be cleared before the discovery mode is changed.

See also

clear()

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.error()
Return type

Error

Returns the type of error that last occurred. If the service discovery is done for a single remoteAddress() it will return errors that occurred while trying to discover services on that device. If the remoteAddress() is not set and devices are discovered by a scan, errors during service discovery on individual devices are not saved and no signals are emitted. In this case, errors are fairly normal as some devices may not respond to discovery or may no longer be in range. Such errors are surpressed. If no services are returned, it can be assumed no services could be discovered.

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.errorOccurred(error)
Parameters

error – Error

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.errorString()
Return type

str

Returns a human-readable description of the last error that occurred during the service discovery.

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.finished()
PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.isActive()
Return type

bool

Returns true if the service discovery is currently active; otherwise returns false. An active discovery can be stopped by calling stop() .

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.remoteAddress()
Return type

PySide6.QtBluetooth.QBluetoothAddress

Returns the remote device address. If setRemoteAddress() is not called, the function will return a default constructed QBluetoothAddress .

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.serviceDiscovered(info)
Parameters

info – PySide6.QtBluetooth.QBluetoothServiceInfo

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.setRemoteAddress(address)
Parameters

address – PySide6.QtBluetooth.QBluetoothAddress

Return type

bool

Sets the remote device address to address. If address is default constructed, services will be discovered on all contactable Bluetooth devices. A new remote address can only be set while there is no service discovery in progress; otherwise this function returns false.

On some platforms the service discovery might lead to pairing requests. Therefore it is not recommended to do service discoveries on all devices. This function can be used to restrict the service discovery to a particular device.

See also

remoteAddress()

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.setUuidFilter(uuid)
Parameters

uuid – PySide6.QtBluetooth.QBluetoothUuid

This is an overloaded member function, provided for convenience.

Sets the UUID filter to a list containing the single element uuid. The matching applies to the service’s ServiceId and ServiceClassIds attributes.

See also

uuidFilter()

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.setUuidFilter(uuids)
Parameters

uuids –

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.start([mode=QBluetoothServiceDiscoveryAgent.DiscoveryMode.MinimalDiscovery])
Parameters

mode – DiscoveryMode

Starts service discovery. mode specifies the type of service discovery to perform.

On some platforms, device discovery may lead to pairing requests.

See also

DiscoveryMode

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.stop()

Stops the service discovery process. The canceled() signal will be emitted once the search has stopped.

PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent.uuidFilter()
Return type

Returns the UUID filter.

See also

setUuidFilter()