I've a json string request coming from server and I convert it into json object

  StaticJsonBuffer<500> jsonStaticBuffer;
  JsonObject& root = jsonStaticBuffer.parseObject(String(msg));
  String reqId;
  String reqData;

I need to populate another char json string initiated at the beginning

const char response[] = "{\"response\": {\"requestid\":, \"data\":}}"; 

such that I need to write requestid into the response::requestid and data into response::data + ACK/NAK . here is how i've tried;

  DynamicJsonBuffer jsonDynResponse; 
  JsonObject& jsonResponse = jsonDynResponse.parseObject(response);   
  String out;  
  if (ACK) {
      jsonResponse["response"]["requestid"] = root["requestid"]; 
      jsonResponse["response"]["data"] = root["data"] + " ACK"; //THIS DOESN'T WORKS
  } else {
      jsonResponse["response"]["requestid"] = reqId;
      jsonResponse["response"]["data"] = reqData + " NAK";  

I know this will definitely not work root["data"] + " ACK" because we can't combine const char with String. But this reqData + " NAK"; resulted in "\"data\" NAK"". How can I concate root["data"] into another String ? Thank you in advance :)

  • String(root["data"]) + " ACK"? Jan 9 '19 at 5:37
  • Tried that already, I get exit status 1 call of overloaded 'String(ArduinoJson::Internals::JsonObjectSubscript<const char*>)' is ambiguous Jan 9 '19 at 9:46
  • perhaps you need to create a String variable, do things with it, and then jsonResponse["response"]["data"] = whateverYourStringVariableIsCalled; Jan 9 '19 at 9:52
  • The things that I want to do with the string is append ACK/NAK on whatever is in root["data"]. Which I am not able to do. Jan 9 '19 at 15:33

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