NTPClient/NTPClient.cpp

/**
 * The MIT License (MIT)
 * Copyright (c) 2015 by Fabrice Weinberg
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "NTPClient.h"

NTPClient::NTPClient() {}

NTPClient::NTPClient(int timeOffset) {
  this->_timeOffset     = timeOffset;
}

NTPClient::NTPClient(const char* poolServerName) {
  this->_poolServerName = poolServerName;
}

NTPClient::NTPClient(const char* poolServerName, int timeOffset) {
  this->_timeOffset     = timeOffset;
  this->_poolServerName = poolServerName;
}

NTPClient::NTPClient(const char* poolServerName, int timeOffset, int updateInterval) {
  this->_timeOffset     = timeOffset;
  this->_poolServerName = poolServerName;
  this->_updateInterval = updateInterval;
}

void NTPClient::forceUpdate() {
  #ifdef DEBUG_NTPClient
    Serial.println("Update from NTP Server");
  #endif

  IPAddress address;
  WiFi.hostByName(this->_poolServerName, address);

  this->sendNTPPacket(address);

  // Wait till data is there or timeout...
  byte timeout = 0;
  int cb = 0;
  do {
    delay ( 10 );
    cb = this->_udp.parsePacket();
    if (timeout > 100) return; // timeout after 1000 ms
    timeout++;
  } while (cb == 0);

  this->_lastUpdate = millis() - (10 * (timeout + 1)); // Account for delay in reading the time

  this->_udp.read(this->_packetBuffer, NTP_PACKET_SIZE);

  unsigned long highWord = word(this->_packetBuffer[40], this->_packetBuffer[41]);
  unsigned long lowWord = word(this->_packetBuffer[42], this->_packetBuffer[43]);
  // combine the four bytes (two words) into a long integer
  // this is NTP time (seconds since Jan 1 1900):
  unsigned long secsSince1900 = highWord << 16 | lowWord;

  this->_currentEpoc = secsSince1900 - SEVENZYYEARS;
}

void NTPClient::update() {
  if ((millis() - this->_lastUpdate >= this->_updateInterval)     // Update after _updateInterval
    || this->_lastUpdate == 0) {                                // Update if there was no update yet.
    if (this->_lastUpdate == 0) this->_udp.begin(this->_port);  // Start _udp if there was no update yet.
    this->forceUpdate();
  }
}

unsigned long NTPClient::getRawTime() {
  return this->_timeOffset + // User offset
         this->_currentEpoc + // Epoc returned by the NTP server
         ((millis() - this->_lastUpdate) / 1000); // Time since last update
}

String NTPClient::getHours() {
  return String((this->getRawTime()  % 86400L) / 3600);
}
String NTPClient::getMinutes() {
  return String((this->getRawTime() % 3600) / 60);
}

String NTPClient::getSeconds() {
  return String(this->getRawTime() % 60);
}

String NTPClient::getFormattedTime() {
  unsigned long rawTime = this->getRawTime();
  unsigned long hours = (rawTime % 86400L) / 3600;
  String hoursStr = hours < 10 ? "0" + String(hours) : String(hours);

  unsigned long minutes = (rawTime % 3600) / 60;
  String minuteStr = minutes < 10 ? "0" + String(minutes) : String(minutes);

  unsigned long seconds = rawTime % 60;
  String secondStr = seconds < 10 ? "0" + String(seconds) : String(seconds);

  return hoursStr + ":" + minuteStr + ":" + secondStr;
}

void NTPClient::sendNTPPacket(IPAddress ip) {
  // set all bytes in the buffer to 0
  memset(this->_packetBuffer, 0, NTP_PACKET_SIZE);
  // Initialize values needed to form NTP request
  // (see URL above for details on the packets)
  this->_packetBuffer[0] = 0b11100011;   // LI, Version, Mode
  this->_packetBuffer[1] = 0;     // Stratum, or type of clock
  this->_packetBuffer[2] = 6;     // Polling Interval
  this->_packetBuffer[3] = 0xEC;  // Peer Clock Precision
  // 8 bytes of zero for Root Delay & Root Dispersion
  this->_packetBuffer[12]  = 49;
  this->_packetBuffer[13]  = 0x4E;
  this->_packetBuffer[14]  = 49;
  this->_packetBuffer[15]  = 52;

  // all NTP fields have been given values, now
  // you can send a packet requesting a timestamp:
  this->_udp.beginPacket(ip, 123); //NTP requests are to port 123
  this->_udp.write(this->_packetBuffer, NTP_PACKET_SIZE);
  this->_udp.endPacket();
}