Arduino MEGA met Ethernet shield

//==== edit "myCredentials_org.h" ========
//==== and save it as "myCredentials.h" ==
#include "myCredentials.h"
​
#include <ArduinoHttpClient.h>    // tested with version 0.4.0
#include <Ethernet.h>
#include <SPI.h>
​
//------ [ArduinoJson@6.19.3]
#include <ArduinoJson.h>
//-- if you need more fields make this JsonDocument bigger
StaticJsonDocument<350> dsmrDoc;
//-- if you need more fields make this JsonDocument bigger
StaticJsonDocument<150> filter;
​
#define _READINTERVAL     30000
​
const char *DSMRprotocol  = "http://";
const char *DSMRserverIP  = _DSMR_IP_ADDRESS;
const char *DSMRrestAPI   = "/api/v2/sm/actual";
String      payload;
int         httpResponseCode;
uint32_t    lastRead = 0;
​
//--- catch specific fields for further processing -------
//--- these are just an example! see readDsmrLogger() ----
String  timeStamp;
float   energyDelivered, pwrDelivered; 
float   energyReturned,  pwrReturned;
float   gasDelivered;
bool    firstCall = true;
​
//--------------------------------------------------------------------------
bool dsmrGETrequest() 
{
  EthernetClient ETHclient;
  HttpClient DSMRclient = HttpClient(ETHclient, DSMRserverIP, 80);
​
  payload = ""; 
   
  Serial.println(F("making GET request"));
  DSMRclient.get(DSMRrestAPI);
​
  // read the response code and body of the response
  httpResponseCode = DSMRclient.responseStatusCode();
​
  if (httpResponseCode <= 0)
  {
    Serial.print(F("http Response Code: "));
    Serial.println(httpResponseCode);
    return false;
  }
​
  payload    = DSMRclient.responseBody();
​
  deserializeJson(dsmrDoc, payload, DeserializationOption::Filter(filter));
​
  // Free resources
  DSMRclient.stop();
​
  if (firstCall)
  {
    Serial.print("dsmrDoc::");
    serializeJsonPretty(dsmrDoc, Serial);
    Serial.println();
  }
  firstCall = false;
​
  return true;
  
} // dsmrGETrequest()
​
//--------------------------------------------------------------------------
void readDsmrLogger()
{
  int fieldNr = 0;
​
  dsmrGETrequest();
​
  //-- store the fields you are interested in ----------
  timeStamp         = dsmrDoc["actual"]["timestamp"].as<const char*>();
  energyDelivered   = dsmrDoc["actual"]["energy_delivered_tariff1"].as<float>()
                    + dsmrDoc["actual"]["energy_delivered_tariff2"].as<float>();
  pwrDelivered      = dsmrDoc["actual"]["power_delivered"].as<float>();
  energyReturned    = dsmrDoc["actual"]["energy_returned_tariff1"].as<float>()
                    + dsmrDoc["actual"]["energy_returned_tariff2"].as<float>();
  pwrReturned       = dsmrDoc["actual"]["power_returned"].as<float>();
  gasDelivered      = dsmrDoc["actual"]["gas_delivered"].as<float>();
​
  if (firstCall)
  {
    Serial.println();
    Serial.println(F("==== Start parsing payload ======================="));
​
    for (JsonPair p : dsmrDoc["actual"].as<JsonObject>())
    {
      Serial.print(p.key().c_str()); Serial.print("\t: ");
      if (p.value().is<int>())              Serial.println(p.value().as<int>());
      else if (p.value().is<float>())       Serial.println(p.value().as<float>());
      else if (p.value().is<const char*>()) Serial.println(p.value().as<const char*>());
      else Serial.println("unknown type");
    }
    Serial.println(F("=================================================="));
  }
      
} // readDsmrLogger()
​
​
//--------------------------------------------------------------------------
void setup() 
{
  Serial.begin(115200);
  while(!Serial) { /* wait a bit */ }
​
  Serial.println("");
  Serial.println(F("\r\n***************************************"));
  Serial.println(F("And then it all begins ..."));
  Serial.println(F("***************************************\r\n"));
​
  //-- The filter: it contains "true" for each value we want to capture
  filter["actual"]["timestamp"] = true;
  filter["actual"]["power_delivered"] = true;
  filter["actual"]["power_returned"] = true;
  filter["actual"]["gas_delivered"] = true;
  filter["actual"]["energy_delivered_tariff1"] = true;
  filter["actual"]["energy_delivered_tariff2"] = true;
  filter["actual"]["energy_returned_tariff1"] = true;
  filter["actual"]["energy_returned_tariff2"] = true;
  Serial.print("filterDoc::");
  serializeJsonPretty(filter, Serial);
  Serial.println();
​
  // Initialize Ethernet library
  byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
​
  if (!Ethernet.begin(mac)) 
  {
    Serial.println(F("Failed to configure Ethernet"));
    return;
  }
  delay(1000);
​
  lastRead = millis() + _READINTERVAL;
​
  Serial.println(F("\r\nStart reading ..."));
​
} // setup()
​
​
//--------------------------------------------------------------------------
void loop() 
{
  if ((millis() - lastRead) > _READINTERVAL)
  {
    lastRead = millis();
    Serial.print(F("\r\nread API/v2 from DSMR-logger @"));
    Serial.println(_DSMR_IP_ADDRESS);
    readDsmrLogger();
    Serial.println(F("\r\nCaptured fields ==============================="));
    Serial.print(F("timestamp       : ")); Serial.println(timeStamp);
    Serial.print(F("energyDelivered : ")); Serial.println(energyDelivered);
    Serial.print(F("pwrDelivered    : ")); Serial.println(pwrDelivered);
    Serial.print(F("energyReturned  : ")); Serial.println(energyReturned);
    Serial.print(F("pwrReturned     : ")); Serial.println(pwrReturned);
    Serial.print(F("gasDelivered    : ")); Serial.println(gasDelivered);
    Serial.println(F("\r\n"));
  }
  
} // loop()