How to pass JsonObject from ArduinoJson to ESP8266WebServer object?

Question

I am learning the ArduinoJson.h library and creating jsonOject:

JsonObject& prepareResponse(JsonBuffer& jsonBuffer) {
 JsonObject& root = jsonBuffer.createObject();
 JsonArray& tempValues = root.createNestedArray("temperature");
 tempValues.add(t);
 JsonArray& humiValues = root.createNestedArray("humidity");
 humiValues.add(h);
 JsonArray& dewpValues = root.createNestedArray("dewpoint");
 dewpValues.add(pfDew);
 JsonArray& EsPvValues = root.createNestedArray("systemv");
 EsPvValues.add(pfVcc / 1000, 3);
 return root;
}

As per the example given here. However since I am using an ESP8266WebServer to create a server object from ESP8266WebServer.h, I cannot pass a JsonObject to server.send(.....).

no matching function for call to 'ESP8266WebServer::send(int, const char [10], ArduinoJson::JsonObject&)'

void outputJson() {
 StaticJsonBuffer<500> jsonBuffer;
 JsonObject& json = prepareResponse(jsonBuffer);
 writeResponse(client, json);
 server.send ( 200, "text/json", json );
}
void writeResponse(WiFiClient& clnt, JsonObject& json) {
 clnt.println("HTTP/1.1 200 OK");
 clnt.println("Content-Type: application/json");
 clnt.println("Access-Control-Allow-Origin: *");
 clnt.println("Connection: close");
 clnt.println();
 json.prettyPrintTo(clnt);
}

Answer 1

As far as I know, the only way is to serialize the JsonObject to a String:

String createJsonResponse() {
 StaticJsonBuffer<500> jsonBuffer;
 JsonObject &root = jsonBuffer.createObject();
 JsonArray &tempValues = root.createNestedArray("temperature");
 tempValues.add(t);
 JsonArray &humiValues = root.createNestedArray("humidity");
 humiValues.add(h);
 JsonArray &dewpValues = root.createNestedArray("dewpoint");
 dewpValues.add(pfDew);
 JsonArray &EsPvValues = root.createNestedArray("systemv");
 EsPvValues.add(pfVcc / 1000, 3);
 String json;
 root.prettyPrintTo(json);
 return json;
}
void outputJson() {
 server.send(200, "text/json", createJsonResponse());
}

By the way, I recommend that you use the ArduinoJson Assistant to compute the size of the JsonBuffer.

• Ciasto piekarz: thanks I did tried the suggested already but forgot to get rid of the other stuff from outputJson. Thank you very much . greatly appreciated (y)