class QBluetoothSocket¶

The QBluetoothSocket class enables connection to a Bluetooth device running a bluetooth server. More…

Synopsis¶

Methods¶

def __init__()
def abort()
def connectToService()
def disconnectFromService()
def doDeviceDiscovery()
def error()
def localAddress()
def localName()
def localPort()
def peerAddress()
def peerName()
def peerPort()
def preferredSecurityFlags()
def setPreferredSecurityFlags()
def setSocketDescriptor()
def setSocketError()
def setSocketState()
def socketDescriptor()
def socketType()
def state()

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description¶

QBluetoothSocket supports two socket types, L2CAP and RFCOMM .

L2CAP is a low level datagram-oriented Bluetooth socket. Android does not support L2CAP for socket connections.

RFCOMM is a reliable, stream-oriented socket. RFCOMM sockets emulate an RS-232 serial port.

To create a connection to a Bluetooth service, create a socket of the appropriate type and call connectToService() passing the Bluetooth address and port number. QBluetoothSocket will emit the connected() signal when the connection is established.

If the Protocol is not supported on a platform, calling connectToService() will emit a UnsupportedProtocolError error.

Note

QBluetoothSocket does not support synchronous read and write operations. Functions such as waitForReadyRead() and waitForBytesWritten() are not implemented. I/O operations should be performed using readyRead(), read() and write().

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

Note

On macOS Monterey (12) the socket data flow is paused when a modal dialogue is executing, or an event tracking mode is entered (for example by long-pressing a Window close button). This may change in the future releases of macOS.

class SocketState¶

This enum describes the state of the Bluetooth socket.

Constant

Description

QBluetoothSocket.SocketState.UnconnectedState

Socket is not connected.

QBluetoothSocket.SocketState.ServiceLookupState

Socket is querying connection parameters.

QBluetoothSocket.SocketState.ConnectingState

Socket is attempting to connect to a device.

QBluetoothSocket.SocketState.ConnectedState

Socket is connected to a device.

QBluetoothSocket.SocketState.BoundState

Socket is bound to a local address and port.

QBluetoothSocket.SocketState.ClosingState

Socket is connected and will be closed once all pending data is written to the socket.

QBluetoothSocket.SocketState.ListeningState

Socket is listening for incoming connections.

Constant	Description
QBluetoothSocket.SocketState.UnconnectedState	Socket is not connected.
QBluetoothSocket.SocketState.ServiceLookupState	Socket is querying connection parameters.
QBluetoothSocket.SocketState.ConnectingState	Socket is attempting to connect to a device.
QBluetoothSocket.SocketState.ConnectedState	Socket is connected to a device.
QBluetoothSocket.SocketState.BoundState	Socket is bound to a local address and port.
QBluetoothSocket.SocketState.ClosingState	Socket is connected and will be closed once all pending data is written to the socket.
QBluetoothSocket.SocketState.ListeningState	Socket is listening for incoming connections.

class SocketError¶

This enum describes Bluetooth socket error types.

Constant

Description

QBluetoothSocket.SocketError.UnknownSocketError

An unknown error has occurred.

QBluetoothSocket.SocketError.NoSocketError

No error. Used for testing.

QBluetoothSocket.SocketError.HostNotFoundError

Could not find the remote host.

QBluetoothSocket.SocketError.ServiceNotFoundError

Could not find the service UUID on remote host.

QBluetoothSocket.SocketError.NetworkError

Attempt to read or write from socket returned an error

QBluetoothSocket.SocketError.UnsupportedProtocolError

The Protocol is not supported on this platform.

QBluetoothSocket.SocketError.OperationError

An operation was attempted while the socket was in a state that did not permit it.

QBluetoothSocket.SocketError.RemoteHostClosedError

The remote host closed the connection.

QBluetoothSocket.SocketError.MissingPermissionsError

The operating system requests permissions which were not granted by the user.

Constant	Description
QBluetoothSocket.SocketError.UnknownSocketError	An unknown error has occurred.
QBluetoothSocket.SocketError.NoSocketError	No error. Used for testing.
QBluetoothSocket.SocketError.HostNotFoundError	Could not find the remote host.
QBluetoothSocket.SocketError.ServiceNotFoundError	Could not find the service UUID on remote host.
QBluetoothSocket.SocketError.NetworkError	Attempt to read or write from socket returned an error
QBluetoothSocket.SocketError.UnsupportedProtocolError	The `Protocol` is not supported on this platform.
QBluetoothSocket.SocketError.OperationError	An operation was attempted while the socket was in a state that did not permit it.
QBluetoothSocket.SocketError.RemoteHostClosedError	The remote host closed the connection.
QBluetoothSocket.SocketError.MissingPermissionsError	The operating system requests permissions which were not granted by the user.

__init__([parent=None])¶

Parameters:: parent – QObject

Constructs a Bluetooth socket with parent.

__init__(socketType[, parent=None])

Parameters:

socketType – Protocol
parent – QObject

Constructs a Bluetooth socket of socketType type, with parent.

abort()¶

Aborts the current connection and resets the socket. Unlike disconnectFromService() , this function immediately closes the socket, discarding any pending data in the write buffer.

Note

On Android, aborting the socket requires asynchronous interaction with Android threads. Therefore the associated disconnected() and stateChanged() signals are delayed until the threads have finished the closure.

See also

disconnectFromService() close()

connectToService(service[, openMode=QIODeviceBase.OpenModeFlag.ReadWrite])¶

Parameters:

service – QBluetoothServiceInfo
openMode – Combination of OpenModeFlag

Attempts to connect to the service described by service.

The socket is opened in the given openMode. The socketType() is ignored if service specifies a differing socketProtocol() .

The socket first enters ConnectingState and attempts to connect to the device providing service. If a connection is established, QBluetoothSocket enters ConnectedState and emits connected() .

At any point, the socket can emit errorOccurred() to signal that an error occurred.

Note that most platforms require a pairing prior to connecting to the remote device. Otherwise the connection process may fail.

On Android, only RFCOMM connections are possible. This function ignores any socket protocol indicator and assumes RFCOMM.

See also

state() disconnectFromService()

connectToService(address, uuid[, mode=QIODeviceBase.OpenModeFlag.ReadWrite])

Parameters:

address – QBluetoothAddress
uuid – ServiceClassUuid
mode – Combination of OpenModeFlag

connectToService(address, uuid[, openMode=QIODeviceBase.OpenModeFlag.ReadWrite])

Parameters:

address – QBluetoothAddress
uuid – QBluetoothUuid
openMode – Combination of OpenModeFlag

Attempts to make a connection to the service identified by uuid on the device with address address.

The socket is opened in the given openMode.

For BlueZ, the socket first enters the ServiceLookupState and queries the connection parameters for uuid. If the service parameters are successfully retrieved the socket enters ConnectingState , and attempts to connect to address. If a connection is established, QBluetoothSocket enters ConnectedState and emits connected() .

On Android, the service connection can directly be established using the UUID of the remote service. Therefore the platform does not require the ServiceLookupState and socketType() is always set to RfcommProtocol .

At any point, the socket can emit errorOccurred() to signal that an error occurred.

Note that most platforms require a pairing prior to connecting to the remote device. Otherwise the connection process may fail.

See also

state() disconnectFromService()

connectToService(address, port[, openMode=QIODeviceBase.OpenModeFlag.ReadWrite])

Parameters:

address – QBluetoothAddress
port – int
openMode – Combination of OpenModeFlag

Attempts to make a connection with address on the given port.

The socket is opened in the given openMode.

The socket first enters ConnectingState , and attempts to connect to address. If a connection is established, QBluetoothSocket enters ConnectedState and emits connected() .

At any point, the socket can emit errorOccurred() to signal that an error occurred.

On Android and BlueZ (version 5.46 or above), a connection to a service can not be established using a port. Calling this function will emit a ServiceNotFoundError .

Note that most platforms require a pairing prior to connecting to the remote device. Otherwise the connection process may fail.

See also

state() disconnectFromService()

connected()¶

This signal is emitted when a connection is established.

See also

ConnectedState stateChanged()

disconnectFromService()¶

Attempts to close the socket. If there is pending data waiting to be written QBluetoothSocket will enter ClosingState and wait until all data has been written. Eventually, it will enter UnconnectedState and emit the disconnected() signal.

See also

connectToService()

disconnected()¶

This signal is emitted when the socket is disconnected.

See also

UnconnectedState stateChanged()

doDeviceDiscovery(service, openMode)¶

Parameters:

service – QBluetoothServiceInfo
openMode – Combination of OpenModeFlag

Start device discovery for service and open the socket with openMode. If the socket is created with a service uuid device address, use service discovery to find the port number to connect to.

error()¶

Return type:: SocketError

Returns the last error.

errorOccurred(error)¶

Parameters:: error – SocketError

This signal is emitted when an error occurs.

See also

error()

localAddress()¶

Return type:: QBluetoothAddress

Returns the address of the local device.

Although some platforms may differ the socket must generally be connected to guarantee the return of a valid address. In particular, this is true when dealing with platforms that support multiple local Bluetooth adapters.

localName()¶

Return type:: str

Returns the name of the local device.

Although some platforms may differ the socket must generally be connected to guarantee the return of a valid name. In particular, this is true when dealing with platforms that support multiple local Bluetooth adapters.

localPort()¶

Return type:: int

Returns the port number of the local socket if available, otherwise returns 0. Although some platforms may differ the socket must generally be connected to guarantee the return of a valid port number.

On Android and macOS, this feature is not supported and returns 0.

peerAddress()¶

Return type:: QBluetoothAddress

Returns the address of the peer device.

peerName()¶

Return type:: str

Returns the name of the peer device.

peerPort()¶

Return type:: int

Return the port number of the peer socket if available, otherwise returns 0. On Android, this feature is not supported.

preferredSecurityFlags()¶

Return type:: Combination of Security

Returns the security parameters used for the initial connection attempt.

The security parameters may be renegotiated between the two parties during or after the connection has been established. If such a change happens it is not reflected in the value of this flag.

On macOS, this flag is always set to Secure .

See also

setPreferredSecurityFlags()

setPreferredSecurityFlags(flags)¶

Parameters:: flags – Combination of Security

Sets the preferred security parameter for the connection attempt to flags. This value is incorporated when calling connectToService() . Therefore it is required to reconnect to change this parameter for an existing connection.

On Bluez this property is set to Authorization by default.

On macOS, this value is ignored as the platform does not permit access to the security parameter of the socket. By default the platform prefers secure/encrypted connections though and therefore this function always returns Secure .

Android only supports two levels of security (secure and non-secure). If this flag is set to NoSecurity the socket object will not employ any authentication or encryption. Any other security flag combination will trigger a secure Bluetooth connection. This flag is set to Secure by default.

Note

A secure connection requires a pairing between the two devices. On some platforms, the pairing is automatically initiated during the establishment of the connection. Other platforms require the application to manually trigger the pairing before attempting to connect.