Arduino JSON foreach loop

Question

I'm trying to extract values using ArduinoJson. The values aren't fixed, therefore I need to use the foreach loop.

I'm trying this, but I can't seem to use the values like I could with.

root["0"]["value"].as<const char*>();

Here is my code.

void loop(){
 int httpCode = http.GET();
 if(httpCode > 0) {
 // if Get request has processed
 if(httpCode == HTTP_CODE_OK) {
 payload = http.getString();
 }
 if(payload.length() > 0) {
 Serial.println(payload);
 JsonObject& root = jsonBuffer.parseObject(payload);
 if (!root.success()) {
 Serial.println("parseObject() failed");
 jsonBuffer.clear();
 } else {
 Serial.println("Data Fetched");
 for(JsonPair& node : root) {
 Serial.print("0 State: ");
 Serial.println(*node);
 }
 http.end();
 }
 } else {
 Serial.println("Payload Empty");
 }
 }
}

Please avoid any missing brackets. Thanks in advance.

[{"state": true, "value": 10}, {"state": false, "value": 8}, {"state": false, "value": 5}, {"state": false, "value": 13}]

• Maximilian Gerhardt: How can we possible answer this question if we don't know what JSON will be fed in and what error occurs?
• Jaromanda X: wouldn't it be root[0]["value"]?
• jsotola: what does this mean? avoid any missing brackets .... how do you avoid something that does not exist?
• Sheraz Ahmed: @jsotola I meant to say please avoid if I missed some bracket in the code above. Nevermind...
• dda: You should press ctrl-T and indent your code properly, as a start...

Answer 1

I found another way around the solution.

Idk if this is helpful to anyone but the problem was that I had an unknown number of nodes I wanted to loop through, Example of the json format above.

void loop(){
int httpCode = http.GET();
 if(httpCode > 0) {
 // if Get request has processed
 if(httpCode == HTTP_CODE_OK) {
 payload = http.getString();
 }
 if(payload.length() > 0){
 JsonArray& nodes = jsonBuffer.parseArray(payload);
 if (!nodes.success()) {
 Serial.println("parseObject() failed");
 jsonBuffer.clear();
 }else{
 int node_length = nodes.size(); 
 for(int i=0; i<node_length;i++){
 Serial.printf("node-%i\nValue : ",i );
 String value = nodes[i]["value"].as<const char*>();
 String state = nodes[i]["state"].as<const char*>();
 Serial.println(value);
 Serial.print("State : ");
 Serial.println(state); 
 }
 http.end();
 }
 }else{
 Serial.println("Payload Empty");
 }
 }
 jsonBuffer.clear();
 delay(8000);
}

• Juraj: so you found out that the json array has a size property?
• Sheraz Ahmed: Yes both jsonArray and jsonObject has size property