ESP-WROOM-02でグローバルIPを取得

gistfile1.txt

String findPublicIP() {
  WiFiClient client;
  if (client.connect("api.ipify.org", 80)) {
    //Serial.println("connected");
    client.println("GET /?format=txt HTTP/1.0");
    client.println("Host: api.ipify.org");
    client.println();
  } else {
    Serial.println("connection failed");
  }
  delay(50);
  int a = 1;
  while (client.connected()) {
    a = a + 1;
    String line = client.readStringUntil('\n');
    if (a == 10) {
      Serial.println(line);
      return line;
    }
  }
  return "";
}