cant read json data esp 32 "parseObject() failed"

Question

hello I am just trying to make Youtube Subscribe Counter with led matrix 32*8 and esp 32 and I had this problem when I trying to get subscribers to count so what is the problem and how I can fix it? `

 ``` //######################## YouTube Subscriber Count Display on LED MATRIX #############################
 // Receives and displays YouTube channel statistics
 //################# LIBRARIES ################
 String version = "v1.0"; // Version of this program
 
 #include <WiFi.h>
 #include <WiFiClientSecure.h>
 #include <ArduinoJson.h> // https://github.com/bblanchon/ArduinoJson
 #include <SPI.h>
 #include <Adafruit_GFX.h>
 #include <Max72xxPanel.h> // https://github.com/markruys/arduino-Max72xxPanel
 #include <time.h>
 //################ VARIABLES ################
 // Use your own API key by signing up for a free Youtube developer account at http://www.youtube.com
 // LED Matrix Pin -> ESP32 Pin
 // Vcc -> 3v 
 // Gnd -> Gnd 
 // DIN -> MOSI pin use results of print statement 23 maybe
 // CS -> SS pin use results of print statement 5 maybe
 // CLK -> SCK pin use results of print statement 18 maybe
 
 const char* channelId = "UCqTSLaEj9c4hiZkU0FfbaJA"; // See your Channel details click on your channel icon at top-right, then Settings, then Advanced
 const char* apiKey = "A--------------Aw"; // See https://developers.google.com/youtube/v3/getting-started for an API key, you must enable it to make it work!
 const char* host = "https://www.googleapis.com";
 unsigned long lastConnectionTime = 0; // Last time you connected to the server, in milliseconds
 const unsigned long postingInterval = 10L*60L*1000L; // Delay between updates, in milliseconds, you should limit your YouTube requests per-day maximum
 
 //################ PROGRAM VARIABLES and OBJECTS ################
 int pinCS = 5; // Attach CS to this pin, DIN to MOSI and CLK to SCK (cf http://arduino.cc/en/Reference/SPI )
 int numberOfHorizontalDisplays = 4;
 int numberOfVerticalDisplays = 1;
 int wait = 35; // In milliseconds
 int spacer = 1;
 int width = 5 + spacer; // The font width is 5 pixels
 int port = 443;
 String time_str;
 
 Max72xxPanel matrix = Max72xxPanel(pinCS, numberOfHorizontalDisplays, numberOfVerticalDisplays);
 
 struct channelStatistics{
 long viewCount;
 long commentCount;
 long subscriberCount;
 bool hiddenSubscriberCount;
 long videoCount;
 };
 
 // Change to your WiFi credentials
 const char* ssid = "SSid";
 const char* password = "PASS";
 
 channelStatistics channelStats;
 
 void setup() {
 Serial.begin(115200); // initialize serial communications
 Serial.println("Mosi="+String(MOSI));
 Serial.println("SS="+String(SS));
 Serial.println("SCK="+String(SCK));
 StartWiFi(ssid,password);
 StartTime();
 
 //----------------------------------------------------------------------
 configTime(0 * 3600, 0, "pool.ntp.org", "time.nist.gov");
 matrix.setIntensity(0); // Use a value between 0 and 15 for brightness
 // Adjust the LED matrix to your own needs
 // matrix.setPosition(0, 0, 0); // The first display is at <0, 0>
 // matrix.setPosition(1, 1, 0); // The second display is at <1, 0>
 // matrix.setPosition(2, 2, 0); // The third display is at <2, 0>
 // matrix.setPosition(3, 3, 0); // And the last display is at <3, 0>
 // ...
 matrix.setRotation(0, 1); // The first display is position is rotated
 matrix.setRotation(1, 1); // The first display is position is rotated
 matrix.setRotation(2, 1); // The first display is position is rotated
 matrix.setRotation(3, 1); // The first display is position is rotated
 lastConnectionTime = millis();
 obtain_subscriber_stats();
 }
 
 void loop() {
 display_message("Subs: " + String(channelStats.subscriberCount));
 time_t now = time(nullptr);
 String time = String(ctime(&now));
 time.trim();
 display_message(" on " + time);
 if (millis() - lastConnectionTime > postingInterval) { // 15-minutes
 obtain_subscriber_stats();
 lastConnectionTime = millis();
 }
 }
 
 //################ PROGRAM FUNCTIONS ################
 
 void display_message(String message){ // Scroll the image left
 matrix.fillScreen(LOW);
 for ( int i = 0 ; i < width * message.length() + matrix.width() - 1 - spacer; i++ ) {
 int letter = i / width;
 int x = (matrix.width() - 1) - i % width;
 int y = (matrix.height() - 8) / 2; // center the text vertically
 while ( x + width - spacer >= 0 && letter >= 0 ) {
 if (letter < message.length()) matrix.drawChar(x, y, message[letter], HIGH, LOW, 1); // HIGH means foreground on, LOW means background off, LOW< HIGH inverts the display
 letter--;
 x -= width;
 }
 matrix.write(); // Send bitmap to display
 delay(wait);
 }
 }
 
 void obtain_subscriber_stats() {
 String command = "https://www.googleapis.com/youtube/v3/channels?part=statistics&id=" + String(channelId);
 String response = GetRequestFromYoutube(command); 
 StaticJsonBuffer <200> jsonBuffer;
 JsonObject& root = jsonBuffer.parseObject(response); // Parse JSON
 if (!root.success()) {
 Serial.println(F("jsonBuffer.parseObject() failed"));
 }
 else
 {
 
 JsonObject& current = root["items"][0]["statistics"]; 
 long subscriberCount = current["subscriberCount"];
 long viewCount = current["viewCount"];
 long commentCount = current["commentCount"];
 long hiddenSubscriberCount = current["hiddenSubscriberCount"];
 long videoCount = current["videoCount"];
 channelStats.viewCount = viewCount;
 channelStats.subscriberCount = subscriberCount;
 channelStats.commentCount = commentCount;
 channelStats.hiddenSubscriberCount = hiddenSubscriberCount;
 channelStats.videoCount = videoCount;
 
 
 } 
 Serial.println(" View Count = " + String(channelStats.viewCount));
 Serial.println("Subscriber Count = " + String(channelStats.subscriberCount));
 Serial.println(GetRequestFromYoutube(command));
 Serial.println(response);
 // Serial.println(jsonBuffer.parseObject(response));
 
 }
 
 String GetRequestFromYoutube(String request) {
 String headers, body = "";
 bool Headers = false;
 bool currentLineIsBlank = true;
 int MessageLength = 1000;
 // Connect with youtube api over ssl
 WiFiClientSecure client;
 if (client.connect(host, port)) {
 Serial.println(".... connected to server");
 char c;
 int ch_count=0;
 request += "&key=" + String(apiKey);
 request = "GET " + request;
 Serial.println(request);
 client.println(request);
 int now = millis();
 while (millis()-now < 1500) {
 while (client.available()) {
 char c = client.read();
 if(!Headers){
 if (currentLineIsBlank && c == '\n') {
 Headers = true;
 }
 else{
 headers = headers + c;
 }
 } else {
 if (ch_count < MessageLength) {
 body = body+c;
 ch_count++;
 }
 }
 if (c == '\n') {
 currentLineIsBlank = true;
 } else if (c != '\r') {
 currentLineIsBlank = false;
 }
 }
 }
 }
 return body;
 }
 
 ////////////// WiFi, Time and Date Functions /////////////////
 int StartWiFi(const char* ssid, const char* password) {
 int connAttempts = 0;
 Serial.print(F("\r\nConnecting to: ")); Serial.println(String(ssid));
 WiFi.begin(ssid, password);
 while (WiFi.status() != WL_CONNECTED ) {
 delay(500); Serial.print(".");
 if (connAttempts > 20) {
 Serial.println("\nFailed to connect to a Wi-Fi network");
 return -5;
 }
 connAttempts++;
 }
 Serial.print(F("WiFi connected at: "));
 Serial.println(WiFi.localIP());
 return 1;
 }
 
 void StartTime(){
 configTime(0, 0, "0.uk.pool.ntp.org", "time.nist.gov");
 setenv("TZ", "GMT0BST,M3.5.0/01,M10.5.0/02",1); // Change for your location
 UpdateLocalTime();
 }
 
 void UpdateLocalTime(){
 struct tm timeinfo;
 while (!getLocalTime(&timeinfo)){
 Serial.println("Failed to obtain time");
 }
 //See http://www.cplusplus.com/reference/ctime/strftime/
 Serial.println(&timeinfo, "%a %b %d %Y %H:%M:%S"); // Displays: Saturday, June 24 2017 14:05:49
 char output[50];
 strftime(output, 50, "%a %d-%b-%y (%H:%M:%S)", &timeinfo);
 time_str = output;
 }
 ```

• jsotola: why are you not providing all information? ... I am very certain that the error message is longer than parseObject() failed
• abdalrahmanabs: this is the full problem if you read the code you will find this if statment ``` JsonObject& root = jsonBuffer.parseObject(response); // Parse JSON if (!root.success()) { Serial.println(F("jsonBuffer.parseObject() failed")); }``` it just printing this message in the serial monitor
• Sim Son: print the content and take a look at the byre json. It's probably either too long too fit into 200 bytes or the formating is broken.

Answer 1

The documentation for ArduinoJson 5 lists the reasons why parseObject() may return false:

1. The input is not a valid JSON
2. The StaticJsonBuffer is too small
3. The StaticJsonBuffer is too big (stack overflow)
4. The DynamicJsonBuffer fails to allocate memory
5. You called parseObject() instead of parseArray()
6. The nesting limit is too low

A glance at your code suggests that the problem is number 2: the StaticJsonBuffer is too small. Indeed, I don't know what the input looks like, but 200 bytes is probably too small to store the result.

You can use the ArduinoJson Assistant to compute the required capacity for the JsonBuffer. Don't forget to switch to a DynamicJsonBuffer if it becomes bigger than 4 KB.

Lastly, I really recommend that you switch to ArduinoJson 6 because it offers more features, better performance, better memory usage, and better error reporting, all with the same code size and portability.