Wokwi - Online ESP32, STM32, Arduino Simulator

#include <WiFi.h>

WiFiServer server(80);

String header;

unsigned long currentTime = millis();
unsigned long previousTime = 0; 
const long timeoutTime = 2000;

String outputState;

void setup() 
{
  pinMode(2, OUTPUT);
  Serial.begin(9600);
  
  WiFi.begin("soc2019","socka2019");
  while(WiFi.status() != WL_CONNECTED)
  {
    delay(250);
    Serial.print(".");
  }

  Serial.println("WiFi uspesne pripojena!");
  Serial.print("IP adresa: ");
  Serial.println(WiFi.localIP());

  server.begin();
}

void loop()
{
  WiFiClient client = server.available(); // aktualizovanie prijatych dat

  if (client) // ak sa pripojil klient
  {
    currentTime = millis();
    previousTime = currentTime;
    Serial.println("Novy klient");
    String currentLine = ""; // premenna pre prijate data
    while (client.connected() && currentTime - previousTime <= timeoutTime) 
    { 
      currentTime = millis();
      if (client.available()) // test ci su prijate dake data
      {
        char c = client.read(); // nacitanie bajtu z buffera
        Serial.write(c);
        header += c;

        if (c == '\n') // po ENTER je request 
        {
          if (currentLine.length() == 0) // ak sa nacital prazdny riadok, odosli potvrdenie o spojeni
          {
            client.println("HTTP/1.1 200 OK");
            client.println("Content-type:text/html");
            client.println("Connection: close");
            client.println("");

            if (header.indexOf("GET /2/on") >= 0)
            {
              Serial.println("LED 2 on");
              outputState = "on";
              digitalWrite(2, HIGH);
            }
            else if (header.indexOf("GET /2/off") >= 0)
            {
                Serial.println("LED 2 off");
                outputState = "off";
                digitalWrite(2, LOW);
            }

            client.println("<!DOCTYPE html>");
            client.println("<html>");
            client.println("<head><style> p   {color: blue;} h1 {color</style></head>");
            client.println("<body><h1>ESP32 <a href=\"https://www.spsknm.sk/ssknm/\">web</a> server</h1>");
            client.println("<p>LED " + outputState + "</p>");

            if (outputState == "off")
                client.println("<p><a href=\"/2/on\"><button class=\"button\">ON</button></a></p>");
            else
                client.println("<p><a href=\"/2/off\"><button class=\"button button2\">OFF</button></a></p>");

            client.println("</body></html>");
            client.println();
            break;
          }
          else 
          {
            currentLine = "";
          }
        } 
        else if (c != '\r') 
        {  
          currentLine += c;      // add it to the end of the currentLine
        }
      }
    }
    
    header = "";
    client.stop();
    Serial.println("Klient je odpojeny.");
    Serial.println("");
  }
}