Add cfgMqttWattJson to extract a value from a JSON string (#54)

steff393 · Feb 11, 2023 · 49e1444 · 49e1444
1 parent f42c98c
commit 49e1444
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Showing 3 changed files with 22 additions and 1 deletion.
diff --git a/src/globalConfig.cpp b/src/globalConfig.cpp
@@ -28,6 +28,7 @@ char     cfgMqttUser[32];             // MQTT: Username
 char     cfgMqttPass[32];             // MQTT: Password
 uint8_t  cfgMqttLp[WB_CNT];           // Array with assignments to openWB loadpoints, e.g. [4,2,0,1]: Box0 = LP4, Box1 = LP2, Box2 = no MQTT, Box3 = LP1
 char     cfgMqttWattTopic[60];        // MQTT: Topic for setting the watt value for PV charging, default: "wbec/pv/setWatt"
+char     cfgMqttWattJson[15];         // MQTT: Optional: Element in a JSON string, which contains the power in watt, default: ""
 char     cfgNtpServer[30];            // NTP server
 char     cfgFoxUser[32];              // powerfox: Username
 char     cfgFoxPass[16];              // powerfox: Password
@@ -136,6 +137,7 @@ void loadConfig() {
 	strncpy(cfgMqttUser,        doc["cfgMqttUser"]           | "",                 sizeof(cfgMqttUser));
 	strncpy(cfgMqttPass,        doc["cfgMqttPass"]           | "",                 sizeof(cfgMqttPass));
 	strncpy(cfgMqttWattTopic,   doc["cfgMqttWattTopic"]      | "wbec/pv/setWatt",  sizeof(cfgMqttWattTopic));
+	strncpy(cfgMqttWattJson,    doc["cfgMqttWattJson"]       | "",                 sizeof(cfgMqttWattJson));
 	strncpy(cfgNtpServer,       doc["cfgNtpServer"]          | "europe.pool.ntp.org", sizeof(cfgNtpServer));
 	strncpy(cfgFoxUser,         doc["cfgFoxUser"]            | "",                 sizeof(cfgFoxUser));
 	strncpy(cfgFoxPass,         doc["cfgFoxPass"]            | "",                 sizeof(cfgFoxPass));

diff --git a/src/globalConfig.h b/src/globalConfig.h
@@ -39,6 +39,7 @@ extern char     cfgMqttUser[32];             // MQTT: Username
 extern char     cfgMqttPass[32];             // MQTT: Password
 extern uint8_t  cfgMqttLp[WB_CNT];           // Array with assignments to openWB loadpoints, e.g. [4,2,0,1]: Box0 = LP4, Box1 = LP2, Box2 = no MQTT, Box3 = LP1
 extern char     cfgMqttWattTopic[60];        // MQTT: Topic for setting the watt value for PV charging, default: "wbec/pv/setWatt"
+extern char     cfgMqttWattJson[15];         // MQTT: Optional: Element in a JSON string, which contains the power in watt, default: ""
 extern char     cfgNtpServer[30];            // NTP server
 extern char     cfgFoxUser[32];              // powerfox: Username
 extern char     cfgFoxPass[16];              // powerfox: Password

diff --git a/src/mqtt.cpp b/src/mqtt.cpp
@@ -1,6 +1,7 @@
 // Copyright (c) 2021 steff393, MIT license
 
 #include <Arduino.h>
+#include <ArduinoJson.h>
 #include <ESP8266WiFi.h>
 #include <globalConfig.h>
 #include <inverter.h>
@@ -10,6 +11,10 @@
 #include <PubSubClient.h>
 #include <pvAlgo.h>
 
+
+#define MAX_JSON_LEN        200
+
+
 const uint8_t m = 2;
 
 WiFiClient espClient;
@@ -95,7 +100,20 @@ void callback(char* topic, byte* payload, uint8_t length)
 
 	// set the watt value via MQTT (#54)
 	if (strcmp(topic, cfgMqttWattTopic) == 0) {
-		pv_setWatt(atol(buffer));
+		if (strcmp(cfgMqttWattJson, "") == 0) {
+			// directly take the value from the buffer
+			pv_setWatt(atol(buffer));
+		} else {
+			// extract the value from a JSON string
+			StaticJsonDocument<MAX_JSON_LEN> doc;
+			// Parse JSON object
+			DeserializationError error = deserializeJson(doc, buffer);
+			if (error) {
+				LOG(m, "deserializeJson() failed: %s", error.f_str())
+			} else {
+				pv_setWatt((long) doc[cfgMqttWattJson].as<float>());
+			}
+		}
 	}
 
 	callbackActive = false;