Ich war im Zuge eines aktuellen Projekts etwas genervt davon, jedes Mal wenn ich auf ein anderes MQTT-Topic etwas publishen wollte, dazu extra eine MQTT-Device-Instanz anlegen muss. Darum habe ich mir diese Funktion geschrieben, welche im Hintergrund eine temporäre Instanz nutzt. Ich brauche nur die ID der MQTT-Server-Instanz anzugeben, das Topic sowie die Payload.
/* Publish a given payload over a MQTT server under
a given topic without having to manually create a
MQTT server device */
function MQTT_Publish($server_id, $topic, $payload, $retain = false) {
// ensure server instance exists
if(!IPS_InstanceExists($server_id)) {
return false;
}
// convert array structure to json string
if(is_array($payload)) $payload = json_encode($payload);
// determine data type
if(is_string($payload)) {
$ips_var_type = 3;
} else if(is_float($payload)) {
$ips_var_type = 2;
} else if(is_int($payload)) {
$ips_var_type = 1;
} else if(is_bool($payload)) {
$ips_var_type = 0;
} else { // unsupported
return false;
}
$module_id = "{01C00ADD-D04E-452E-B66A-D253278743FE}" /* Module ID of MQTT Server Device */;
$ident = "TempMQTTDevice";
// enter semaphore to ensure the temporary device gets used by one thread at a time
if(IPS_SemaphoreEnter($ident, 100)) {
// get temporary MQTT Server Device or create if needed
$id = @IPS_GetObjectIDByIdent($ident, $_IPS['SELF']);
if($id === false) {
$id = @IPS_CreateInstance($module_id);
if($id === false) {
return false;
}
IPS_SetParent($id, $_IPS['SELF']);
IPS_SetIdent($id, $ident);
}
// ensure the specified server instance is actually compatible
if(!IPS_IsInstanceCompatible($id, $server_id)) {
return false;
}
// ensure that the temporary device is actually connected to the correct server instance
$inst_config = IPS_GetInstance($id);
if($inst_config["ConnectionID"] != $server_id) {
IPS_DisconnectInstance($id);
if(!@IPS_ConnectInstance($id, $server_id)) {
return false;
}
}
// name object to help with debugging
IPS_SetName($id, "Temporary MQTT Server Device for topic " . $topic);
// configure temporary device
$config_arr = array(
"Retain" => $retain,
"Topic" => $topic,
"Type" => $ips_var_type
);
$config_str = json_encode($config_arr);
IPS_SetConfiguration($id, $config_str);
IPS_ApplyChanges($id);
// get Value variable and use it to publish the payload
$var_id = @IPS_GetObjectIDByIdent("Value", $id);
RequestAction($var_id, $payload);
IPS_SemaphoreLeave($ident);
} else { // semaphore timeout
return false;
}
return true;
} // MQTT_Publish
