class QWebSocket

Implements a TCP socket that talks the WebSocket protocol. More…

Inheritance diagram of PySide6.QtWebSockets.QWebSocket

Synopsis

Methods

Slots

Signals

Static functions

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

WebSockets is a web technology providing full-duplex communications channels over a single TCP connection. The WebSocket protocol was standardized by the IETF as RFC 6455 in 2011. QWebSocket can both be used in a client application and server application.

This class was modeled after QAbstractSocket.

QWebSocket currently does not support WebSocket Extensions .

QWebSocket only supports version 13 of the WebSocket protocol, as outlined in RFC 6455 .

Note

Some proxies do not understand certain HTTP headers used during a WebSocket handshake. In that case, non-secure WebSocket connections fail. The best way to mitigate against this problem is to use WebSocket over a secure connection.

Warning

To generate masks, this implementation of WebSockets uses the reasonably secure QRandomGenerator::global()->generate() function. For more information about the importance of good masking, see “Talking to Yourself for Fun and Profit” by Lin-Shung Huang et al . The best measure against attacks mentioned in the document above, is to use QWebSocket over a secure connection (wss://). In general, always be careful to not have 3rd party script access to a QWebSocket in your application.

See also

QWebSocket client example

__init__([origin=""[, version=QWebSocketProtocol.VersionLatest[, parent=None]]])
Parameters:

Creates a new QWebSocket with the given origin, the version of the protocol to use and parent.

The origin of the client is as specified in RFC 6454 . (The origin is not required for non-web browser clients (see RFC 6455 )). The origin may not contain new line characters, otherwise the connection will be aborted immediately during the handshake phase.

Note

Currently only V13 ( RFC 6455 ) is supported

abort()

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

aboutToClose()

This signal is emitted when the socket is about to close. Connect this signal if you have operations that need to be performed before the socket closes (e.g., if you have data in a separate buffer that needs to be written to the device).

See also

close()

alertReceived(level, type, description)
Parameters:

QWebSocket emits this signal if an alert message was received from a peer. level tells if the alert was fatal or it was a warning. type is the code explaining why the alert was sent. When a textual description of the alert message is available, it is supplied in description.

Note

The signal is mostly for informational and debugging purposes and does not require any handling in the application. If the alert was fatal, underlying backend will handle it and close the connection.

Note

Not all backends support this functionality.

See also

alertSent() AlertType

alertSent(level, type, description)
Parameters:

QWebSocket emits this signal if an alert message was sent to a peer. level describes if it was a warning or a fatal error. type gives the code of the alert message. When a textual description of the alert message is available, it is supplied in description.

Note

This signal is mostly informational and can be used for debugging purposes, normally it does not require any actions from the application.

Note

Not all backends support this functionality.

See also

alertReceived() AlertType

authenticationRequired(authenticator)
Parameters:

authenticator – QAuthenticator

This signal is emitted when the server requires authentication. The authenticator object must then be filled in with the required details to allow authentication and continue the connection.

If you know that the server may require authentication, you can set the username and password on the initial QUrl, using QUrl::setUserName and QUrl::setPassword. QWebSocket will still try to connect once without using the provided credentials.

Note

It is not possible to use a QueuedConnection to connect to this signal, as the connection will fail if the authenticator has not been filled in with new information when the signal returns.

See also

QAuthenticator

binaryFrameReceived(frame, isLastFrame)
Parameters:

This signal is emitted whenever a binary frame is received. The frame contains the data and isLastFrame indicates whether this is the last frame of the complete message.

This signal can be used to process large messages frame by frame, instead of waiting for the complete message to arrive.

binaryMessageReceived(message)
Parameters:

message – QByteArray

This signal is emitted whenever a binary message is received. The message contains the received bytes.

bytesToWrite()
Return type:

int

Returns the number of bytes that are waiting to be written. The bytes are written when control goes back to the event loop or when flush() is called.

See also

flush

bytesWritten(bytes)
Parameters:

bytes – int

This signal is emitted every time a payload of data has been written to the socket. The bytes argument is set to the number of bytes that were written in this payload.

Note

This signal has the same meaning both for secure and non-secure WebSockets. As opposed to QSslSocket, bytesWritten() is only emitted when encrypted data is effectively written (see QSslSocket::encryptedBytesWritten()).

See also

close()

close([closeCode=QWebSocketProtocol.CloseCodeNormal[, reason=""]])
Parameters:

Gracefully closes the socket with the given closeCode and reason.

Any data in the write buffer is flushed before the socket is closed. The closeCode is a CloseCode indicating the reason to close, and reason describes the reason of the closure more in detail. All control frames, including the Close frame, are limited to 125 bytes. Since two of these are used for closeCode the maximum length of reason is 123! If reason exceeds this limit it will be truncated.

closeCode()
Return type:

CloseCode

Returns the code indicating why the socket was closed.

closeReason()
Return type:

str

Returns the reason why the socket was closed.

See also

closeCode()

connected()

Emitted when a connection is successfully established. A connection is successfully established when the socket is connected and the handshake was successful.

continueInterruptedHandshake()

If an application wants to conclude a handshake even after receiving handshakeInterruptedOnError() signal, it must call this function. This call must be done from a slot function attached to the signal. The signal-slot connection must be direct.

disconnected()

Emitted when the socket is disconnected.

See also

close() connected()

error()
Return type:

SocketError

Returns the type of error that last occurred

See also

errorString()

error(error)
Parameters:

error – SocketError

Note

This function is deprecated.

Use errorOccurred (QAbstractSocket::SocketError error) instead.

errorOccurred(error)
Parameters:

error – SocketError

This signal is emitted after an error occurred.

The error parameter describes the type of error that occurred.

QAbstractSocket::SocketError is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType().

errorString()
Return type:

str

Returns a human-readable description of the last error that occurred

See also

error()

flush()
Return type:

bool

This function writes as much as possible from the internal write buffer to the underlying network socket, without blocking. If any data was written, this function returns true; otherwise false is returned. Call this function if you need QWebSocket to start sending buffered data immediately. The number of bytes successfully written depends on the operating system. In most cases, you do not need to call this function, because QWebSocket will start sending data automatically once control goes back to the event loop.

handshakeInterruptedOnError(error)
Parameters:

error – QSslError

QWebSocket emits this signal if a certificate verification error was found and if early error reporting was enabled in QSslConfiguration. An application is expected to inspect the error and decide if it wants to continue the handshake, or abort it and send an alert message to the peer. The signal-slot connection must be direct.

handshakeOptions()
Return type:

QWebSocketHandshakeOptions

Returns the handshake options that were used to open this socket.

ignoreSslErrors()

This slot tells QWebSocket to ignore errors during QWebSocket ‘s handshake phase and continue connecting. If you want to continue with the connection even if errors occur during the handshake phase, then you must call this slot, either from a slot connected to sslErrors() , or before the handshake phase. If you don’t call this slot, either in response to errors or before the handshake, the connection will be dropped after the sslErrors() signal has been emitted.

Warning

Be sure to always let the user inspect the errors reported by the sslErrors() signal, and only call this method upon confirmation from the user that proceeding is ok. If there are unexpected errors, the connection should be aborted. Calling this method without inspecting the actual errors will most likely pose a security risk for your application. Use it with great care!

See also

sslErrors() ignoreSslErrors()

ignoreSslErrors(errors)
Parameters:

errors – .list of QSslError

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

This is an overloaded function.

This method tells QWebSocket to ignore the errors given in errors.

Note that you can set the expected certificate in the SSL error: If, for instance, you want to connect to a server that uses a self-signed certificate, consider the following snippet:

cert = QSslCertificate.fromPath("server-certificate.pem")
error = QSslError(QSslError.SelfSignedCertificate, cert.at(0))
expectedSslErrors = QList()
expectedSslErrors.append(error)
socket = QWebSocket()
socket.ignoreSslErrors(expectedSslErrors)
socket.open(QUrl("wss://myserver.at.home"))

Multiple calls to this function will replace the list of errors that were passed in previous calls. You can clear the list of errors you want to ignore by calling this function with an empty list.

See also

sslErrors()

isValid()
Return type:

bool

Returns true if the socket is ready for reading and writing; otherwise returns false.

localAddress()
Return type:

QHostAddress

Returns the local address

localPort()
Return type:

int

Returns the local port

maskGenerator()
Return type:

QMaskGenerator

Returns the mask generator that is currently used by this QWebSocket .

maxAllowedIncomingFrameSize()
Return type:

int

Returns the maximum allowed size of an incoming websocket frame.

maxAllowedIncomingMessageSize()
Return type:

int

Returns the maximum allowed size of an incoming websocket message.

static maxIncomingFrameSize()
Return type:

int

Returns the maximum supported size of an incoming websocket frame for this websocket implementation.

static maxIncomingMessageSize()
Return type:

int

Returns the maximum supported size of an incoming websocket message for this websocket implementation.

static maxOutgoingFrameSize()
Return type:

int

Returns the maximum supported size of an outgoing websocket frame for this websocket implementation.

open(request)
Parameters:

request – QNetworkRequest

Opens a WebSocket connection using the given request.

The request url will be used to open the WebSocket connection. Headers present in the request will be sent to the server in the upgrade request, together with the ones needed for the websocket handshake.

open(url)
Parameters:

url – QUrl

Opens a WebSocket connection using the given url.

If the url contains newline characters (\r\n), then the error signal will be emitted with QAbstractSocket::ConnectionRefusedError as error type.

open(request, options)
Parameters:

Opens a WebSocket connection using the given request and options.

The request url will be used to open the WebSocket connection. Headers present in the request will be sent to the server in the upgrade request, together with the ones needed for the websocket handshake.

Additional options for the WebSocket handshake such as subprotocols can be specified in options.

open(url, options)
Parameters:

Opens a WebSocket connection using the given url and options.

If the url contains newline characters (\r\n), then the error signal will be emitted with QAbstractSocket::ConnectionRefusedError as error type.

Additional options for the WebSocket handshake such as subprotocols can be specified in options.

origin()
Return type:

str

Returns the current origin.

outgoingFrameSize()
Return type:

int

Returns the maximum size of an outgoing websocket frame.

pauseMode()
Return type:

Combination of PauseMode

Returns the pause mode of this socket

See also

setPauseMode()

peerAddress()
Return type:

QHostAddress

Returns the peer address

peerName()
Return type:

str

Returns the peerName

peerPort()
Return type:

int

Returns the peerport

peerVerifyError(error)
Parameters:

error – QSslError

QWebSocket can emit this signal several times during the SSL handshake, before encryption has been established, to indicate that an error has occurred while establishing the identity of the peer. The error is usually an indication that QWebSocket is unable to securely identify the peer.

This signal provides you with an early indication when something’s wrong. By connecting to this signal, you can manually choose to tear down the connection from inside the connected slot before the handshake has completed. If no action is taken, QWebSocket will proceed to emitting sslErrors() .

See also

sslErrors()

ping([payload=QByteArray()])
Parameters:

payload – QByteArray

Pings the server to indicate that the connection is still alive. Additional payload can be sent along the ping message.

The size of the payload cannot be bigger than 125. If it is larger, the payload is clipped to 125 bytes.

Note

QWebSocket and QWebSocketServer handles ping requests internally, which means they automatically send back a pong response to the peer.

See also

pong()

pong(elapsedTime, payload)
Parameters:

Emitted when a pong message is received in reply to a previous ping. elapsedTime contains the roundtrip time in milliseconds and payload contains an optional payload that was sent with the ping.

See also

ping()

preSharedKeyAuthenticationRequired(authenticator)
Parameters:

authenticator – QSslPreSharedKeyAuthenticator

This signal is emitted if the SSL/TLS handshake negotiates a PSK ciphersuite, and therefore a PSK authentication is then required.

When using PSK, the client must send to the server a valid identity and a valid pre shared key, in order for the SSL handshake to continue. Applications can provide this information in a slot connected to this signal, by filling in the passed authenticator object according to their needs.

Note

Ignoring this signal, or failing to provide the required credentials, will cause the handshake to fail, and therefore the connection to be aborted.

Note

The authenticator object is owned by the websocket and must not be deleted by the application.

See also

preSharedKeyAuthenticationRequired()

proxy()
Return type:

QNetworkProxy

Returns the currently configured proxy

See also

setProxy()

proxyAuthenticationRequired(proxy, pAuthenticator)
Parameters:

This signal can be emitted when a proxy that requires authentication is used. The authenticator object can then be filled in with the required details to allow authentication and continue the connection.

Note

It is not possible to use a QueuedConnection to connect to this signal, as the connection will fail if the authenticator has not been filled in with new information when the signal returns.

See also

QAuthenticatorQNetworkProxy

readBufferSize()
Return type:

int

Returns the size in bytes of the readbuffer that is used by the socket.

readChannelFinished()

This signal is emitted when the input (reading) stream is closed in this device. It is emitted as soon as the closing is detected.

See also

close()

request()
Return type:

QNetworkRequest

Returns the request that was or will be used to open this socket.

requestUrl()
Return type:

QUrl

Returns the url the socket is connected to or will connect to.

resourceName()
Return type:

str

Returns the name of the resource currently accessed.

resume()

Continues data transfer on the socket. This method should only be used after the socket has been set to pause upon notifications and a notification has been received. The only notification currently supported is sslErrors() . Calling this method if the socket is not paused results in undefined behavior.

sendBinaryMessage(data)
Parameters:

data – QByteArray

Return type:

int

Sends the given data over the socket as a binary message and returns the number of bytes actually sent.

sendTextMessage(message)
Parameters:

message – str

Return type:

int

Sends the given message over the socket as a text message and returns the number of bytes actually sent.

setMaskGenerator(maskGenerator)
Parameters:

maskGenerator – QMaskGenerator

Sets the generator to use for creating masks to maskGenerator. The default QWebSocket generator can be reset by supplying a nullptr. The mask generator can be changed at any time, even while the connection is open.

See also

maskGenerator()

setMaxAllowedIncomingFrameSize(maxAllowedIncomingFrameSize)
Parameters:

maxAllowedIncomingFrameSize – int

Sets the maximum allowed size of an incoming websocket frame to maxAllowedIncomingFrameSize. If an incoming frame exceeds this limit, the peer gets disconnected. The accepted range is between 0 and maxIncomingFrameSize() , default is maxIncomingFrameSize() . The purpose of this function is to avoid exhausting virtual memory.

setMaxAllowedIncomingMessageSize(maxAllowedIncomingMessageSize)
Parameters:

maxAllowedIncomingMessageSize – int

Sets the maximum allowed size of an incoming websocket message to maxAllowedIncomingMessageSize. If an incoming message exceeds this limit, the peer gets disconnected. The accepted range is between 0 and maxIncomingMessageSize() , default is maxIncomingMessageSize() . The purpose of this function is to avoid exhausting virtual memory.

setOutgoingFrameSize(outgoingFrameSize)
Parameters:

outgoingFrameSize – int

Sets the maximum size of an outgoing websocket frame to outgoingFrameSize. The accepted range is between 0 and maxOutgoingFrameSize() , default is 512kB. The purpose of this function is to adapt to the maximum allowed frame size of the receiver.

setPauseMode(pauseMode)
Parameters:

pauseMode – Combination of PauseMode

Controls whether to pause upon receiving a notification. The pauseMode parameter specifies the conditions in which the socket should be paused.

The only notification currently supported is sslErrors() . If set to PauseOnSslErrors, data transfer on the socket will be paused and needs to be enabled explicitly again by calling resume() . By default, this option is set to PauseNever. This option must be called before connecting to the server, otherwise it will result in undefined behavior.

setProxy(networkProxy)
Parameters:

networkProxy – QNetworkProxy

Sets the proxy to networkProxy

See also

proxy()

setReadBufferSize(size)
Parameters:

size – int

Sets the size of QWebSocket ‘s internal read buffer to be size bytes.

If the buffer size is limited to a certain size, QWebSocket won’t buffer more than this size of data. Exceptionally, a buffer size of 0 means that the read buffer is unlimited and all incoming data is buffered. This is the default. This option is useful if you only read the data at certain points in time (for example, in a real-time streaming application) or if you want to protect your socket against receiving too much data, which may eventually cause your application to run out of memory.

See also

readBufferSize()

setSslConfiguration(sslConfiguration)
Parameters:

sslConfiguration – QSslConfiguration

Sets the socket’s SSL configuration to be the contents of sslConfiguration.

This function sets the local certificate, the ciphers, the private key and the CA certificates to those stored in sslConfiguration. It is not possible to set the SSL-state related fields.

sslConfiguration()
Return type:

QSslConfiguration

Returns the socket’s SSL configuration state. The default SSL configuration of a socket is to use the default ciphers, default CA certificates, no local private key or certificate. The SSL configuration also contains fields that can change with time without notice.

sslErrors(errors)
Parameters:

errors – .list of QSslError

QWebSocket emits this signal after the SSL handshake to indicate that one or more errors have occurred while establishing the identity of the peer. The errors are usually an indication that QWebSocket is unable to securely identify the peer. Unless any action is taken, the connection will be dropped after this signal has been emitted. If you want to continue connecting despite the errors that have occurred, you must call ignoreSslErrors() from inside a slot connected to this signal. If you need to access the error list at a later point, you can call sslErrors() (without arguments).

errors contains one or more errors that prevent QWebSocket from verifying the identity of the peer.

Note

You cannot use Qt::QueuedConnection when connecting to this signal, or calling ignoreSslErrors() will have no effect.

state()
Return type:

SocketState

Returns the current state of the socket.

stateChanged(state)
Parameters:

state – SocketState

This signal is emitted whenever QWebSocket ‘s state changes. The state parameter is the new state.

Note

QAbstractSocket::ConnectedState is emitted after the handshake with the server has succeeded.

QAbstractSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_REGISTER_METATYPE() and qRegisterMetaType().

See also

state()

subprotocol()
Return type:

str

Returns the used WebSocket protocol.

textFrameReceived(frame, isLastFrame)
Parameters:

  • frame – str

  • isLastFrame – bool

This signal is emitted whenever a text frame is received. The frame contains the data and isLastFrame indicates whether this is the last frame of the complete message.

This signal can be used to process large messages frame by frame, instead of waiting for the complete message to arrive.

textMessageReceived(message)
Parameters:

message – str

This signal is emitted whenever a text message is received. The message contains the received text.

version()
Return type:

Version

Returns the version the socket is currently using.