mqttSession (Type of variable)

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Properties specific to the description of mqttSession variables
Authentication mode
Functions that handle the mqttSession variables

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Managing MQTT

mqttSession (Type of variable)

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 modified by several WLanguage properties.

Note: See Declaring a variable for more details on the declaration of this type of variable and the use of WLanguage properties.

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

Remarks

Properties specific to the description of 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 given in the following format: 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.
PrivateKey	Character string or Certificate variable	Name of Certificate variable to use or files of pem keys (to establish a connection by private key). If this property is specified, an authentication by key is performed: only ..User, ..PrivateKey and ..PrivateKeyPassword are taken into account.
ClientID	Character string	Client identifier. This property must not be left empty.
PrivateKeyPassword	Character string	Password of key file (for a connection by private key). ..PrivateKey corresponds to the private key to use.
UserPassword	Character string	User password used for an authentication by password (..User corresponds to the user name).
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).
CleanSession	Boolean	True to clean the generic global parameters on the server, False otherwise.
ConnectionTimeout	Integer ou Duration	Connection timeout in seconds. This property can correspond to: an integer corresponding to the number of seconds, a Duration variable, Versions 23 and later the direct indication of duration (10 s for example). New in version 23 the direct indication of duration (10 s for example). the direct indication of duration (10 s for example).
User	Character string	User name.

Note: These properties can be handled by using one of the following syntaxes:

<Variable name>..<Property name>
<Variable name>.<Property name>

Authentication mode

The authentication by key has priority over the authentication by password.

The authentication by key is attempted if:

the server supports this authentication mode.
..PrivateKey is filled.

The authentication by password is attempted if:

the server supports this authentication mode.
..UserPassword is filled.

Functions that handle the mqttSession variables

The following functions are used to handle the mqttSession variables:


Versions 22 and later MQTTConnect New in version 22 MQTTConnect MQTTConnect	Used to connect to a MQTT server (also called "Broker").
Versions 22 and later MQTTDisconnect New in version 22 MQTTDisconnect MQTTDisconnect	Allows you to disconnect from a MQTT server (also called "Broker").
Versions 22 and later MQTTPublish New in version 22 MQTTPublish MQTTPublish	Publishes a message on the MQTT broker.
Versions 22 and later MQTTSubscribe New in version 22 MQTTSubscribe MQTTSubscribe	Used to subscribe to a MQTT notification.
Versions 22 and later MQTTUnsubscribe New in version 22 MQTTUnsubscribe MQTTUnsubscribe	Used to unsubscribe from a MQTT notification.
Versions 22 and later MQTTUnsubscribeAll New in version 22 MQTTUnsubscribeAll MQTTUnsubscribeAll	Allows you to unsubscribe from all the existing subscriptions.