mqttSession (Variable type)

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Properties specific to mqttSession variables
Authentication mode
Functions that use mqttSession variables

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Managing MQTT

mqttSession (Variable type)

In french: mqttSession

The mqttSession type is used to define the parameters for connecting to the MQTT broker. These connection parameters can be defined and changed by several WLanguage properties.

Note: For more details on the declaration of this type of variable and the use of WLanguage properties, see Declaring a variable.

Example

// Declare the MQTT connection
gMqttSession is mqttSession

// Retrieve the data typed in the connection window
gMqttSession.Address = EDT_Broker_Address
gMqttSession.Port = EDT_Port
gMqttSession.Option = CBOX_SSL
gMqttSession.ConnectionTimeout = EDT_Connection_Timeout
gMqttSession.User = EDT_Login
gMqttSession.UserPassword = EDT_PSW
gMqttSession.PrivateKey = EDT_Private_Key
gMqttSession.PrivateKeyPassword = EDT_Private_Key_PSW
gMqttSession.ClientID = EDT_ClientID
gMqttSession.CleanSession = CBOX_Clean_Session
IF MQTTConnect(gMqttSession) THEN
	Message("Connection OK")
ELSE
	Error("Connection problem. '" + ErrorInfo() + "')")
END

Properties

Properties specific to mqttSession variables

The following properties can be used to handle a MQTT session:

Property name	Type used	Effect

Address	Character string	Address of MQTT server (also called "MQTT broker"). This address can be specified as follows: IP address in XXX.XXX.XXX.XXX format (125.5.110.100 for example). IP address containing the server name (MQTTServer for example). This syntax is recommended.
CleanSession	Boolean	True to clean the generic global parameters on the server, False otherwise.
ClientID	Character string	Client identifier. This property must not be left empty.
ConnectionTimeout	Integer or Duration	Connection timeout in seconds. This property can correspond to: an integer corresponding to the number of seconds, a Duration variable, the duration in a readable format (e.g., 10 s).
IgnoreError	Integer constant	Specifies the ignored errors. Corresponds to a constant or to a combination of constants: mqttIgnoreCertificateExpired The certificate date is ignored. mqttIgnoreCertificateInvalid The certificate is ignored. mqttIgnoreCertificateNameInvalid: The site name in the certificate is ignored. mqttIgnoreRevocation: Certificate revocation is ignored.
Option	Integer constant	Connection options. This property can correspond to the optionSSL constant for an SSL connection.
Port	Integer	Port of MQTT server. This port correspondsn to 1883 by default (or 8883 for an SSL connection).
PrivateKey	Character string or Certificate variable	Name of the Certificate variable or path of the pem file (to make a private key connection). If this property is set, authentication by key is performed: only the properties User, PrivateKey and PrivateKeyPassword are taken into account..
PrivateKeyPassword	Character string or Secret string	Password of the key file (for a private-key based authentication). The PrivateKey property corresponds to the private key to be used. New in version 2025 Secret strings: If you use the secret string vault, the type of secret string used for this parameter must be "ANSI string - Latin". To learn more about secret strings and how to use the vault, see Secret string vault.
User	Character string	Username.
UserPassword	Character string or Secret string	User password (the User property corresponds to the user's name). New in version 2025 Secret strings: If you use the secret string vault, the type of secret string used for this parameter must be "ANSI or Unicode string". To learn more about secret strings and how to use the vault, see Secret string vault.

Remarks

Authentication mode

Key-based authentication takes precedence over password-based authentication.

Key-based authentication is used if:

the server supports this authentication mode.
the PrivateKey property is specified.

Password-based authentication is used if:

the server supports this authentication mode.
property UserPassword is set.

Functions that use mqttSession variables

The following functions use mqttSession variables:


MQTTConnect	Used to connect to a MQTT server (also called "Broker").
MQTTDisconnect	Allows you to disconnect from a MQTT server (also called "Broker").
MQTTPublish	Publishes a message on the MQTT broker.
MQTTSubscribe	Used to subscribe to a MQTT notification.
MQTTUnsubscribe	Used to unsubscribe from a MQTT notification.
MQTTUnsubscribeAll	Allows you to unsubscribe from all the existing subscriptions.