class QCoapClient

The QCoapClient class allows the application to send CoAP requests and receive replies. More…

Inheritance diagram of PySide6.QtCoap.QCoapClient

Synopsis

Methods

Signals

Note

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Detailed Description

The QCoapClient class contains signals that get triggered when the reply of a sent request has arrived.

The application can use a QCoapClient to send requests over a CoAP network. It provides functions for standard requests: each returns a QCoapReply object, to which the response data shall be delivered; this can be read when the finished() signal arrives.

A simple request can be sent with:

QCoapClient *client = new QCoapClient(this);
connect(client, &QCoapClient::finished, this, &TestClass::slotFinished);
client->get(QCoapRequest(Qurl("coap://coap.me/test")));

Note

After processing of the request has finished, it is the responsibility of the user to delete the QCoapReply object at an appropriate time. Do not directly delete it inside the slot connected to finished() . You can use the deleteLater() function.

You can also use an observe request. This can be used as above, or more conveniently with the notified() signal:

QCoapRequest request = QCoapRequest(Qurl("coap://coap.me/obs"));
QCoapReply *reply = client->observe(request);
connect(reply, &QCoapReply::notified, this, &TestClass::slotNotified);

And the observation can be cancelled with:

client->cancelObserve(reply);

When a reply arrives, the QCoapClient emits a finished() signal.

Note

For a discovery request, the returned object is a QCoapResourceDiscoveryReply . It can be used the same way as a QCoapReply but contains also a list of resources.

See also

QCoapRequest QCoapReply QCoapResourceDiscoveryReply

__init__([securityMode=QtCoap.SecurityMode.NoSecurity[, parent=None]])
Parameters:

Constructs a QCoapClient object for the given securityMode and sets parent as the parent object.

The default for securityMode is NoSecurity , which disables security.

This connects using a QCoapQUdpConnection; to use a custom transport, sub-class QCoapConnection and pass an instance to one of the other constructors.

cancelObserve(notifiedReply)
Parameters:

notifiedReply – QCoapReply

This is an overloaded function.

Cancels the observation of a resource using the reply notifiedReply returned by the observe() method.

See also

observe()

cancelObserve(url)
Parameters:

url – QUrl

This is an overloaded function.

Cancels the observation of a resource identified by the url.

See also

observe()

deleteResource(request)
Parameters:

request – QCoapRequest

Return type:

QCoapReply

Sends the request using the DELETE method and returns a new QCoapReply object.

deleteResource(url)
Parameters:

url – QUrl

Return type:

QCoapReply

This is an overloaded function.

Sends a DELETE request to the target url.

disconnect()

Closes the open sockets and connections to free the transport.

Note

In the secure mode this needs to be called before changing the security configuration or connecting to another server.

See also

setSecurityConfiguration()

discover(baseUrl[, discoveryPath=QLatin1String("/.well-known/core")])
Parameters:

  • baseUrl – QUrl

  • discoveryPath – str

Return type:

QCoapResourceDiscoveryReply

Discovers the resources available at the given url and returns a new QCoapResourceDiscoveryReply object which emits the discovered() signal whenever the response arrives.

Discovery path defaults to “/.well-known/core”, but can be changed by passing a different path to discoveryPath. Discovery is described in RFC 6690 .

discover([group=QtCoap.MulticastGroup.AllCoapNodesIPv4[, port=QtCoap.DefaultPort[, discoveryPath=QLatin1String("/.well-known/core")]]])
Parameters:
Return type:

QCoapResourceDiscoveryReply

This is an overloaded function.

Discovers the resources available at the endpoints which have joined the group at the given port. Returns a new QCoapResourceDiscoveryReply object which emits the discovered() signal whenever a response arrives. The group is one of the CoAP multicast group addresses and defaults to AllCoapNodesIPv4 .

Discovery path defaults to “/.well-known/core”, but can be changed by passing a different path to discoveryPath. Discovery is described in RFC 6690 .

error(reply, error)
Parameters:

This signal is emitted whenever an error occurs. The reply parameter can be None if the error is not related to a specific QCoapReply . The error parameter contains the error code.

finished(reply)
Parameters:

reply – QCoapReply

This signal is emitted along with the finished() signal whenever a CoAP reply is received, after either a success or an error. The reply parameter will contain a pointer to the reply that has just been received.

get(request)
Parameters:

request – QCoapRequest

Return type:

QCoapReply

Sends the request using the GET method and returns a new QCoapReply object.

get(url)
Parameters:

url – QUrl

Return type:

QCoapReply

This is an overloaded function.

Sends a GET request to url and returns a new QCoapReply object.

observe(request)
Parameters:

request – QCoapRequest

Return type:

QCoapReply

Sends a request to observe the target request and returns a new QCoapReply object which emits the notified() signal whenever a new notification arrives.

observe(request)
Parameters:

request – QUrl

Return type:

QCoapReply

This is an overloaded function.

Sends a request to observe the target url and returns a new QCoapReply object which emits the notified() signal whenever a new notification arrives.

post(request, device)
Parameters:
Return type:

QCoapReply

This is an overloaded function.

Sends the request using the POST method and returns a new QCoapReply object. Uses device content as the payload for this request. A null device is treated as empty content.

Note

The device has to be open and readable before calling this function.

See also

get() put() deleteResource() observe() discover()

post(request[, data=QByteArray()])
Parameters:
Return type:

QCoapReply

Sends the request using the POST method and returns a new QCoapReply object. Uses data as the payload for this request. If data is empty, the payload of the request will be used.

post(url[, data=QByteArray()])
Parameters:
Return type:

QCoapReply

This is an overloaded function.

Sends a POST request to url and returns a new QCoapReply object. Uses data as the payload for this request.

put(request, device)
Parameters:
Return type:

QCoapReply

This is an overloaded function.

Sends the request using the PUT method and returns a new QCoapReply object. Uses device content as the payload for this request. A null device is treated as empty content.

Note

The device has to be open and readable before calling this function.

See also

get() post() deleteResource() observe() discover()

put(request[, data=QByteArray()])
Parameters:
Return type:

QCoapReply

Sends the request using the PUT method and returns a new QCoapReply object. Uses data as the payload for this request. If data is empty, the payload of the request will be used.

put(url[, data=QByteArray()])
Parameters:
Return type:

QCoapReply

This is an overloaded function.

Sends a PUT request to url and returns a new QCoapReply object. Uses data as the payload for this request.

responseToMulticastReceived(reply, message, sender)
Parameters:

This signal is emitted when a unicast response to a multicast request arrives. The reply parameter contains a pointer to the reply that has just been received, message contains the payload and the message details, and sender contains the sender address.

setAckRandomFactor(ackRandomFactor)
Parameters:

ackRandomFactor – float

Sets the ACK_RANDOM_FACTOR value defined in RFC 7252 - Section 4.2 , to ackRandomFactor. This value should be greater than or equal to 1. The default is 1.5.

See also

setAckTimeout()

setAckTimeout(ackTimeout)
Parameters:

ackTimeout – int

Sets the ACK_TIMEOUT value defined in RFC 7252 - Section 4.2 to ackTimeout in milliseconds. The default is 2000 ms.

This timeout only applies to confirmable messages. The actual timeout for reliable transmissions is a random value between ACK_TIMEOUT and ACK_TIMEOUT * ACK_RANDOM_FACTOR.

setBlockSize(blockSize)
Parameters:

blockSize – int

Sets the maximum block size used by the protocol to blockSize when sending requests and receiving replies. The block size must be a power of two.

setMaximumRetransmitCount(maximumRetransmitCount)
Parameters:

maximumRetransmitCount – int

Sets the MAX_RETRANSMIT value defined in RFC 7252 - Section 4.2 to maximumRetransmitCount. This value should be less than or equal to 25. The default is 4.

setMaximumServerResponseDelay(responseDelay)
Parameters:

responseDelay – int

Sets the MAX_SERVER_RESPONSE_DELAY value to responseDelay in milliseconds. The default is 250 seconds.

As defined in RFC 7390 - Section 2.5 , MAX_SERVER_RESPONSE_DELAY is the expected maximum response delay over all servers that the client can send a multicast request to.

setMinimumTokenSize(tokenSize)
Parameters:

tokenSize – int

Sets the minimum token size to tokenSize in bytes. For security reasons it is recommended to use tokens with a length of at least 4 bytes. The default value for this parameter is 4 bytes.

setSecurityConfiguration(configuration)
Parameters:

configuration – QCoapSecurityConfiguration

Sets the security configuration parameters from configuration. Configuration will be ignored if the NoSecurity mode is used.

Note

This method must be called before the handshake starts. If you need to change the security configuration after establishing a secure connection with the server, the client needs to be disconnected first.

See also

disconnect()

setSocketOption(option, value)
Parameters:

Sets the QUdpSocket socket option to value.