QMqttPublishProperties Class

The QMqttPublishProperties class represents configuration options for sending or receiving a message. 更多...

头：	#include <QMqttPublishProperties>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Mqtt) target_link_libraries(mytarget PRIVATE Qt6::Mqtt)
qmake:	QT += mqtt

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公共类型

enum	PublishPropertyDetail { None, PayloadFormatIndicator, MessageExpiryInterval, TopicAlias, ResponseTopic, …, ContentType }
flags	PublishPropertyDetails

公共函数

QMqttPublishProperties::PublishPropertyDetails	availableProperties () const
QString	contentType () const
QByteArray	correlationData () const
quint32	messageExpiryInterval () const
QMqtt::PayloadFormatIndicator	payloadFormatIndicator () const
QString	responseTopic () const
void	setContentType (const QString & type )
void	setCorrelationData (const QByteArray & correlation )
void	setMessageExpiryInterval (quint32 interval )
void	setPayloadFormatIndicator (QMqtt::PayloadFormatIndicator indicator )
void	setResponseTopic (const QString & topic )
void	setSubscriptionIdentifiers (const QList<quint32> & ids )
void	setTopicAlias (quint16 alias )
void	setUserProperties (const QMqttUserProperties & properties )
QList<quint32>	subscriptionIdentifiers () const
quint16	topicAlias () const
QMqttUserProperties	userProperties () const

详细描述

Invoking QMqttClient::publish () to send a message to a broker can include QMqttPublishProperties to provide additional arguments on how the message should be treated on the broker.

Furthermore receiving a message by an instantiated subscription might contain publish properties which have been forwarded or adapted by the server.

注意： Publish properties are part of the MQTT 5.0 specification and cannot be used when connecting with a lower protocol level. See QMqttClient::ProtocolVersion 了解更多信息。

成员类型文档编制

enum QMqttPublishProperties:: PublishPropertyDetail
flags QMqttPublishProperties:: PublishPropertyDetails

This enum type specifies the available properties set by the server or the client when creating a message.

常量	值	描述
`QMqttPublishProperties::None`	`0x00000000`	No property has been specified.
`QMqttPublishProperties::PayloadFormatIndicator`	`0x00000001`	The type of content of the message.
`QMqttPublishProperties::MessageExpiryInterval`	`0x00000002`	The duration a message is valid.
`QMqttPublishProperties::TopicAlias`	`0x00000004`	The topic alias for this message.
`QMqttPublishProperties::ResponseTopic`	`0x00000008`	The topic the receipient should respond to.
`QMqttPublishProperties::CorrelationData`	`0x00000010`	An identifier of the response message.
`QMqttPublishProperties::UserProperty`	`0x00000020`	Additional properties set by the user.
`QMqttPublishProperties::SubscriptionIdentifier`	`0x00000040`	An identifier of subscriptions matching the publication.
`QMqttPublishProperties::ContentType`	`0x00000080`	A description of the content of the message.

The PublishPropertyDetails type is a typedef for QFlags <PublishPropertyDetail>. It stores an OR combination of PublishPropertyDetail values.

成员函数文档编制

QMqttPublishProperties::PublishPropertyDetails QMqttPublishProperties:: availableProperties () const

Returns the available properties specified in this instance. When a message is created, it does not need to include all properties. This function serves as an indicator of those properties which have been explicitly set.

QString QMqttPublishProperties:: contentType () const

Returns the content type of the message.

另请参阅 setContentType ().

QByteArray QMqttPublishProperties:: correlationData () const

Returns the correlation data.

另请参阅 setCorrelationData ().

quint32 QMqttPublishProperties:: messageExpiryInterval () const

Returns the message expiry interval. This value specifies the number of seconds a server is allowed to forward the message. If the interval expires, the server must delete the message and abort publishing it.

另请参阅 setMessageExpiryInterval ().

QMqtt::PayloadFormatIndicator QMqttPublishProperties:: payloadFormatIndicator () const

Returns the payload format indicator.

另请参阅 setPayloadFormatIndicator ().

QString QMqttPublishProperties:: responseTopic () const

Returns the response topic a user should use as a follow up to a request.

另请参阅 setResponseTopic ().

void QMqttPublishProperties:: setContentType (const QString & type )

Sets the content type of the message to type .

另请参阅 contentType ().

void QMqttPublishProperties:: setCorrelationData (const QByteArray & correlation )

Sets the correlation data to correlation .

另请参阅 correlationData ().

void QMqttPublishProperties:: setMessageExpiryInterval ( quint32 interval )

Sets the message expiry interval to interval .

另请参阅 messageExpiryInterval ().

void QMqttPublishProperties:: setPayloadFormatIndicator ( QMqtt::PayloadFormatIndicator indicator )

Sets the payload format indicator to indicator .

另请参阅 payloadFormatIndicator ().

void QMqttPublishProperties:: setResponseTopic (const QString & topic )

Sets the response topic to topic .

另请参阅 responseTopic ().

void QMqttPublishProperties:: setSubscriptionIdentifiers (const QList < quint32 > & ids )

Sets the subscription identifiers to ids .

另请参阅 subscriptionIdentifiers ().

void QMqttPublishProperties:: setTopicAlias ( quint16 alias )

Sets the topic alias for publishing a message to alias . A topic alias value must be greater than zero and less than the maximum topic alias specified by the server.

另请参阅 topicAlias () 和 QMqttServerConnectionProperties::maximumTopicAlias ().

void QMqttPublishProperties:: setUserProperties (const QMqttUserProperties & properties )

Sets the user properties of a message to properties .

另请参阅 userProperties ().

QList < quint32 > QMqttPublishProperties:: subscriptionIdentifiers () const

Returns the subscription identifiers of subscriptions matching the topic filter of the message.

另请参阅 setSubscriptionIdentifiers ().

quint16 QMqttPublishProperties:: topicAlias () const

Returns the topic alias used for publishing a message.

另请参阅 setTopicAlias ().

QMqttUserProperties QMqttPublishProperties:: userProperties () const

Returns the user properties of a message.

另请参阅 setUserProperties ().