add step variable for number fields

ChangeLog.md

@@ -7,6 +7,7 @@
 
 ## Features
 * add support for setting visual ping, IP gateway, MAC from ID, and variant to ebuspicloader
+* add step variable for numeric values to message definition in MQTT integration
 
 
 # 22.4 (2022-09-18)

contrib/etc/ebusd/mqtt-hassio.cfg

@@ -56,7 +56,7 @@
 #   %basetype the base data type ID (e.g. "UCH").
 #   %comment the field comment (if any).
 #   %unit the field unit (if any).
-#   %min and %max the minimum/maximum possible value for number fields.
+#   %min, %max, and %step the minimum/maximum possible value and step value for number fields.
 #   %topic the field (or message) update topic built from the mqtttopic configuration option and/or the %topic variable
 #     defined here.
 
@@ -239,7 +239,8 @@ type_part-by = %type_topic
 type_part-number = ,
   "command_topic":"%topic/set",
   "min":%min,
-  "max":%max%unit_of_measurement%state_class%type_class_number
+  "max":%max,
+  "step":%step%unit_of_measurement%state_class%type_class_number
 
 # HA integration: %type_part variable for sensor %type_topic
 type_part-sensor = %unit_of_measurement%state_class%type_class_sensor

contrib/etc/ebusd/mqtt-integration.cfg

@@ -50,7 +50,7 @@
 #   %basetype the base data type ID (e.g. "UCH").
 #   %comment the field comment (if any).
 #   %unit the field unit (if any).
-#   %min and %max the minimum/maximum possible value for number fields.
+#   %min, %max, and %step the minimum/maximum possible value and step value for number fields.
 #   %topic the field (or message) update topic built from the mqtttopic configuration option and/or the %topic variable
 #     defined here.
 

src/ebusd/mqtthandler.cpp

@@ -1085,7 +1085,20 @@ void MqttHandler::run() {
               }
               if (dt->getMinMax(true, g_publishFormat, &ostr) == RESULT_OK) {
                 values.set("max", ostr.str());
+                ostr.str("");
               }
+              if (dt->readFromRawValue(1, g_publishFormat, &ostr) != RESULT_OK) {
+                // fallback method, when smallest number didn't work
+                int divisor = dt->getDivisor();
+                float step = 1.0f;
+                if (divisor > 1) {
+                  step /= static_cast<float>(divisor);
+                } else if (divisor < 0) {
+                  step *= static_cast<float>(-divisor);
+                }
+                ostr << static_cast<float>(step);
+              }
+              values.set("step", ostr.str());
             }
             if (!m_typeSwitches.empty()) {
               values.reduce(true);