POST request to IFTTT

#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>

const char* ssid = "secret";
const char* password = "secret";

// Get key from https://ifttt.com/services/maker_webhooks/settings
const char* apiKey = "secret";
// Get the maker even name
String makerEvent = "maker_event";

const char* host = "maker.ifttt.com";
const int httpsPort = 443;

extern "C" {
  #include "user_interface.h"
}

void setup() {
  Serial.begin(115200);

  delay(100);

  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.print("WiFi SSID: ");
  Serial.println(ssid);
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());

  Serial.println("[INFO] Sending IFTTT notification...");
  WiFiClient client;

  if (!client.connect(host, 80)) {
    Serial.println("[ERROR] Connection failed");
  }

  Serial.println("[INFO] Client connected");

  String url = "/trigger/" + makerEvent + "/with/key/";
  url += apiKey;

  // Some sample data
  char data[] = "value1=10&value2=20&value3=30";

  Serial.print("Requesting URL: ");
  Serial.println(url);

  client.println(String("POST ") + url + " HTTP/1.1");
  client.println(String("Host: ") + host);
  client.println(String("Content-Type: application/x-www-form-urlencoded"));
  client.print(String("Content-Length: "));
  client.println(sizeof(data));
  client.println();
  client.println(data);
  client.stop();

  Serial.println("[INFO] Client posted");
  return;
}

void loop() {
}

BOARD?=esp8266com:esp8266:d1_mini
PORT?=/dev/cu.wchusbserial1410
BUILD=build
# Arduino CLI version 0.14.0 is used.

.PHONY: default lint all flash clean

default: lint all flash clean

lint:
	cpplint --extensions=ino --filter=-legal/copyright *.ino

all:
	arduino-cli compile --fqbn $(BOARD) --output-dir $(BUILD) ./

flash:
	arduino-cli upload --fqbn $(BOARD) --port $(PORT) --input-dir $(BUILD)

clean:
	rm -r build