parse-http-esp8266-example-sketch

#include <ESP8266WiFi.h>

#define BUTTON 2 // button on GPIO2
#define LED 0 // led on GPIO0

const char* ssid     = "yourwifinetwork";
const char* password = "yourwifipassword";

const char* host = "homesensor.parseapp.com";

String API_KEY = "supersecretapikey";
String Identifier = "sensorname";


boolean lastState;

void setup() {
  Serial.begin(115200);
  
  pinMode(LED, OUTPUT);
  pinMode(BUTTON, INPUT_PULLUP);
  lastState = !digitalRead(BUTTON);
  
  WiFi.begin(ssid, password);
  
  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  
  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void loop() {
  digitalWrite(LED, HIGH);
  delay(50);
  digitalWrite(LED, LOW);
  delay(250);
  
  boolean currentState = !digitalRead(BUTTON);
  
  if (lastState != currentState) {
    sendState(Identifier, currentState); 
    lastState = currentState;
  }
}

void sendState(String identifier, boolean state) {
  
  WiFiClient client;
  const int httpPort = 80;
  if (!client.connect(host, httpPort)) {
    Serial.println("connection failed");
    return;
  }
  
  String stateString = (state) ? "true" : "false";
  String json = "{\"identifier\":\"" + Identifier + "\", \"state\":" + stateString + "}";
  
  String postData;
  postData += "POST /sensor HTTP/1.0 \r\n";
  //postData += "X-Parse-Application-Id: " + APP_ID + "\r\n";
  postData += "X-Parse-REST-API-Key: " + API_KEY + "\r\n";
  postData += "Content-Type: application/json \r\n";
  postData += "Host: " + String(host) + " \r\n";
  postData += "Content-Length: " + String(json.length()) + "\r\n\r\n";
  
  postData += json;
  
  // Send the postdata to the server.
  client.print(postData);
  
  delay(1000);
  
  // Read all the lines of the reply from server and print them to Serial
  while(client.available()){
    String line = client.readStringUntil('\r');
    Serial.print(line);
  }
  Serial.println();
  
  Serial.println("closing connection");
}