Customize play function to support different frequencies

handleplay.ino

void handlePlay() {
  String response = "POSTED";
  response += server.arg("timings");
  readCSV(server.arg("timings"));
  for (int i = 0; i < current_data_length; ++i) {
      Serial.println(signal_data[i]);
  }
  int frequency = server.arg("frequency").toInt();
  irsend.sendRaw(signal_data, current_data_length, frequency);  // Send a raw data capture at frequency given as request parameter.
  server.sendHeader("Access-Control-Allow-Origin", "*");
  server.send(200, "text/plain", response);
}

https://github.com/axelerator/esp8266_ir_blaster