Feature: HTTP power meter: support mW/kW as units

include/Configuration.h

@@ -64,6 +64,7 @@ struct INVERTER_CONFIG_T {
 
 struct POWERMETER_HTTP_PHASE_CONFIG_T {
     enum Auth { None, Basic, Digest };
+    enum Unit { Watts = 0, MilliWatts = 1, KiloWatts = 2 };
     bool Enabled;
     char Url[POWERMETER_MAX_HTTP_URL_STRLEN + 1];
     Auth AuthType;
@@ -73,6 +74,7 @@ struct POWERMETER_HTTP_PHASE_CONFIG_T {
     char HeaderValue[POWERMETER_MAX_HTTP_HEADER_VALUE_STRLEN + 1];
     uint16_t Timeout;
     char JsonPath[POWERMETER_MAX_HTTP_JSON_PATH_STRLEN + 1];
+    Unit PowerUnit;
 };
 using PowerMeterHttpConfig = struct POWERMETER_HTTP_PHASE_CONFIG_T;
 

include/HttpPowerMeter.h

@@ -7,6 +7,7 @@
 #include "Configuration.h"
 
 using Auth_t = PowerMeterHttpConfig::Auth;
+using Unit_t = PowerMeterHttpConfig::Unit;
 
 class HttpPowerMeterClass {
 public:
@@ -25,7 +26,7 @@ private:
     String extractParam(String& authReq, const String& param, const char delimit);
     String getcNonce(const int len);
     String getDigestAuth(String& authReq, const String& username, const String& password, const String& method, const String& uri, unsigned int counter);
-    bool tryGetFloatValueForPhase(int phase, const char* jsonPath);
+    bool tryGetFloatValueForPhase(int phase, const char* jsonPath, Unit_t unit);
     void prepareRequest(uint32_t timeout, const char* httpHeader, const char* httpValue);
     String sha256(const String& data);
 };

src/Configuration.cpp

@@ -175,6 +175,7 @@ bool ConfigurationClass::write()
         powermeter_phase["header_value"] = config.PowerMeter.Http_Phase[i].HeaderValue;
         powermeter_phase["timeout"] = config.PowerMeter.Http_Phase[i].Timeout;
         powermeter_phase["json_path"] = config.PowerMeter.Http_Phase[i].JsonPath;
+        powermeter_phase["unit"] = config.PowerMeter.Http_Phase[i].PowerUnit;
     }
 
     JsonObject powerlimiter = doc.createNestedObject("powerlimiter");
@@ -427,6 +428,7 @@ bool ConfigurationClass::read()
         strlcpy(config.PowerMeter.Http_Phase[i].HeaderValue, powermeter_phase["header_value"] | "", sizeof(config.PowerMeter.Http_Phase[i].HeaderValue));
         config.PowerMeter.Http_Phase[i].Timeout = powermeter_phase["timeout"] | POWERMETER_HTTP_TIMEOUT;
         strlcpy(config.PowerMeter.Http_Phase[i].JsonPath, powermeter_phase["json_path"] | "", sizeof(config.PowerMeter.Http_Phase[i].JsonPath));
+        config.PowerMeter.Http_Phase[i].PowerUnit = powermeter_phase["unit"] | PowerMeterHttpConfig::Unit::Watts;
     }
 
     JsonObject powerlimiter = doc["powerlimiter"];

src/HttpPowerMeter.cpp

@@ -42,7 +42,7 @@ bool HttpPowerMeterClass::updateValues()
             continue;
         }
 
-        if(!tryGetFloatValueForPhase(i, phaseConfig.JsonPath)) {
+        if(!tryGetFloatValueForPhase(i, phaseConfig.JsonPath, phaseConfig.PowerUnit)) {
             MessageOutput.printf("[HttpPowerMeter] Getting the power of phase %d (from JSON fetched with Phase 1 config) failed.\r\n", i + 1);
             MessageOutput.printf("%s\r\n", httpPowerMeterError);
             return false;
@@ -159,7 +159,9 @@ bool HttpPowerMeterClass::httpRequest(int phase, WiFiClient &wifiClient, const S
     httpResponse = httpClient.getString(); // very unfortunate that we cannot parse WifiClient stream directly
     httpClient.end();
 
-    return tryGetFloatValueForPhase(phase, jsonPath);
+    // TODO(schlimmchen): postpone calling tryGetFloatValueForPhase, as it
+    // will be called twice for each phase when doing separate requests.
+    return tryGetFloatValueForPhase(phase, config.JsonPath, config.PowerUnit);
 }
 
 String HttpPowerMeterClass::extractParam(String& authReq, const String& param, const char delimit) {
@@ -217,7 +219,7 @@ String HttpPowerMeterClass::getDigestAuth(String& authReq, const String& usernam
     return authorization;
 }
 
-bool HttpPowerMeterClass::tryGetFloatValueForPhase(int phase, const char* jsonPath)
+bool HttpPowerMeterClass::tryGetFloatValueForPhase(int phase, const char* jsonPath, Unit_t unit)
 {
     FirebaseJson json;
     json.setJsonData(httpResponse);
@@ -227,7 +229,17 @@ bool HttpPowerMeterClass::tryGetFloatValueForPhase(int phase, const char* jsonPa
         return false;
     }
 
-    power[phase] = value.to<float>();
+    power[phase] = value.to<float>(); // this is supposed to be in Watts
+    switch (unit) {
+        case Unit_t::MilliWatts:
+            power[phase] /= 1000;
+            break;
+        case Unit_t::KiloWatts:
+            power[phase] *= 1000;
+            break;
+        default:
+            break;
+    }
     return true;
 }
 

src/WebApi_powermeter.cpp

@@ -39,6 +39,7 @@ void WebApiPowerMeterClass::decodeJsonPhaseConfig(JsonObject const& json, PowerM
     strlcpy(config.HeaderValue, json["header_value"].as<String>().c_str(), sizeof(config.HeaderValue));
     config.Timeout = json["timeout"].as<uint16_t>();
     strlcpy(config.JsonPath, json["json_path"].as<String>().c_str(), sizeof(config.JsonPath));
+    config.PowerUnit = json["unit"].as<PowerMeterHttpConfig::Unit>();
 }
 
 void WebApiPowerMeterClass::onStatus(AsyncWebServerRequest* request)
@@ -71,8 +72,9 @@ void WebApiPowerMeterClass::onStatus(AsyncWebServerRequest* request)
         phaseObject["password"] = String(config.PowerMeter.Http_Phase[i].Password);
         phaseObject["header_key"] = String(config.PowerMeter.Http_Phase[i].HeaderKey);
         phaseObject["header_value"] = String(config.PowerMeter.Http_Phase[i].HeaderValue);
-        phaseObject["json_path"] = String(config.PowerMeter.Http_Phase[i].JsonPath);
         phaseObject["timeout"] = config.PowerMeter.Http_Phase[i].Timeout;
+        phaseObject["json_path"] = String(config.PowerMeter.Http_Phase[i].JsonPath);
+        phaseObject["unit"] = config.PowerMeter.Http_Phase[i].PowerUnit;
     }
 
     response->setLength();

webapp/src/locales/de.json

@@ -574,7 +574,8 @@
         "httpHeaderKeyDescription": "Ein individueller HTTP request header kann hier definiert werden. Das kann z.B. verwendet werden um einen eigenen Authorization header mitzugeben.",
         "httpHeaderValue": "Optional: HTTP request header - Wert",
         "httpJsonPath": "JSON Pfad",
-        "httpJsonPathDescription": "JSON Pfad um den Leistungswert zu finden. Es verwendet die Selektions-Syntax von mobizt/FirebaseJson. Beispiele gibt es unten.",
+        "httpJsonPathDescription": "JSON Pfad um den Leistungswert zu finden. Es verwendet die Selektions-Syntax von mobizt/FirebaseJson. Beispiele gibt es oben.",
+        "httpUnit": "Einheit",
         "httpTimeout": "Timeout",
         "testHttpRequest": "Testen"
     },

webapp/src/locales/en.json

@@ -578,8 +578,9 @@
         "httpHeaderKey": "Optional: HTTP request header - Key",
         "httpHeaderKeyDescription": "A custom HTTP request header can be defined. Might be useful if you have to send something like a custom Authorization header.",
         "httpHeaderValue": "Optional: HTTP request header - Value",
-        "httpJsonPath": "Json path",
+        "httpJsonPath": "JSON path",
-        "httpJsonPathDescription": "JSON path to find the power value in the response. This uses the JSON path query syntax from mobizt/FirebaseJson. See below for some examples.",
+        "httpJsonPathDescription": "JSON path to find the power value in the response. This uses the JSON path query syntax from mobizt/FirebaseJson. See above for examples.",
+        "httpUnit": "Unit",
         "httpTimeout": "Timeout",
         "testHttpRequest": "Run test",
         "milliSeconds": "ms"

webapp/src/types/PowerMeterConfig.ts

@@ -9,6 +9,7 @@ export interface PowerMeterHttpPhaseConfig {
     header_value: string;
     json_path: string;
     timeout: number;
+    unit: number;
 }
 
 export interface PowerMeterConfig {

webapp/src/views/PowerMeterAdminView.vue

@@ -189,6 +189,19 @@
                                 placeholder="total_power"
                                 :tooltip="$t('powermeteradmin.httpJsonPathDescription')" />
 
+                            <div class="row mb-3">
+                                <label for="power_unit" class="col-sm-2 col-form-label">
+                                    {{ $t('powermeteradmin.httpUnit') }}
+                                </label>
+                                <div class="col-sm-10">
+                                    <select id="power_unit" class="form-select" v-model="http_phase.unit">
+                                        <option value="1">mW</option>
+                                        <option value="0">W</option>
+                                        <option value="2">kW</option>
+                                    </select>
+                                </div>
+                            </div>
+
                             <div class="text-center mb-3">
                                 <button type="button" class="btn btn-danger" @click="testHttpRequest(index)">
                                     {{ $t('powermeteradmin.testHttpRequest') }}