esp32-wifi-multicast-server.ino

#include <WiFi.h>
#include <WiFiUdp.h>

WiFiUDP udp;
const char * ssid = "SSID";
const char * password = "PASS";
boolean connected = false;

void setup()
{
  Serial.begin(115200);
  connectToWiFi(ssid, password);
}

void loop()
{
  if (connected) {
    int len = udp.parsePacket();
    if (len > 0) {
      Serial.print("src IP: ");
      Serial.print(udp.remoteIP());
      Serial.print(";    packet: [");
      char buf[len];
      udp.read(buf, len);
      for (int i = 0; i < len; i++) {
        Serial.print((char)buf[i]);
      }
      //String str(buf);
      Serial.println("]");
    }
  }
}

void connectToWiFi(const char * ssid, const char * pwd) {
  Serial.println("Connecting to WiFi network: " + String(ssid));
  // delete old config
  WiFi.disconnect(true);
  //register event handler
  WiFi.onEvent(WiFiEvent);
  //Initiate connection
  WiFi.begin(ssid, pwd);

  Serial.println("Waiting for WIFI connection...");
}

//wifi event handler
void WiFiEvent(WiFiEvent_t event) {
  switch (event) {
    case SYSTEM_EVENT_STA_GOT_IP:
      //When connected set
      Serial.print("WiFi connected! IP address: ");
      Serial.println(WiFi.localIP());
      udp.beginMulticast(IPAddress(224, 0, 1, 3), 7570); //libmapper admin bus multicast
      //udp.begin(7000); //test regular UDP server endpoint
      connected = true;
      break;
    case SYSTEM_EVENT_STA_DISCONNECTED:
      Serial.println("WiFi lost connection");
      connected = false;
      break;
  }
}