HTTP server with ESP32/ESP8266

httpserver.cpp

  // Legacy HTTP-based approach.
  // For it to work, you need to call server.begin(); in the setup function and declare a WiFiServer server(80);
  // see https://github.com/espressif/arduino-esp32/blob/master/libraries/WiFi/examples/SimpleWiFiServer/SimpleWiFiServer.ino
  
  if (incomingClient) {
    Serial.println("client connect");
    digitalWrite(LED_PIN, LOW); // LOW = ON

    while (incomingClient.connected()) {
      if (incomingClient.available() > 0) {
        char command = incomingClient.read();
        switch (command) {
          case '0':
            digitalWrite(RELAY_PIN, LOW);
            break;
          case '1':
            digitalWrite(RELAY_PIN, HIGH);
            break;
          case '\n':
            incomingClient.stop();
            break;
        }
      }
    }
    incomingClient.stop();
    Serial.println("client disconnect");
    digitalWrite(LED_PIN, HIGH); // HIGH = OFF
  }

client

  WiFiClient client;
  if (!client.connect(HOST, PORT)) {
    Serial.println("connection failed");
    return;
  }

  client.print("temp:");
  client.print(temperature);
  client.stop();