Create NTP util class to handle getTime() fallback

Author: facchinm

src/ConnectionManager.h

@@ -23,6 +23,8 @@
 #endif
 
 #include <Client.h>
+#include <Udp.h>
+#include "utility/NTPUtils.h"
 
 enum NetworkConnectionState {
   CONNECTION_STATE_INIT,
@@ -40,6 +42,7 @@ class ConnectionManager {
   virtual void check() = 0;
   virtual unsigned long getTime() = 0;
   virtual Client &getClient();
+  virtual UDP &getUDP();
 
   virtual NetworkConnectionState getStatus() { return netConnectionState; }
 

src/GSMConnectionManager.h

@@ -26,10 +26,12 @@ class GSMConnectionManager : public ConnectionManager {
   virtual void init();
   virtual void check();
   virtual Client &getClient() { return networkClient; };
+  virtual UDP &getUDP() { return udp; };
 
   GSMClient networkClient;
   GSM gsmAccess;
   GPRS gprs;
+  GSMUDP udp;
 private:
 
   void changeConnectionState(NetworkConnectionState _newState);

src/WiFiConnectionManager.h

@@ -25,7 +25,7 @@ class WiFiConnectionManager : public ConnectionManager {
   virtual void init();
   virtual void check();
   virtual Client &getClient() { return wifiClient; };
-  
+  virtual UDP &getUDP() { return udp; };
 
 private:
 

src/utility/NTPUtils.cpp

@@ -0,0 +1,72 @@
+#include "NTPUtils.h"
+#include "Arduino.h"
+
+// could be a constexpr in C++14
+static time_t cvt_TIME(char const *time) {
+    char s_month[5];
+    int month, day, year;
+    struct tm t = {0};
+    static const char month_names[] = "JanFebMarAprMayJunJulAugSepOctNovDec";
+
+    sscanf(time, "%s %d %d", s_month, &day, &year);
+
+    month = (strstr(month_names, s_month)-month_names)/3;
+
+    t.tm_mon = month;
+    t.tm_mday = day;
+    t.tm_year = year - 1900;
+    t.tm_isdst = -1;
+
+    return mktime(&t);
+}
+
+
+NTPUtils::NTPUtils(UDP& Udp) : Udp(Udp) {}
+
+bool NTPUtils::isTimeValid(unsigned long time) {
+    Serial.println("Compile time: " + String(cvt_TIME(__DATE__)));
+    return (time > cvt_TIME(__DATE__));
+}
+
+void NTPUtils::sendNTPpacket(uint8_t* packetBuffer) {
+  memset(packetBuffer, 0, NTP_PACKET_SIZE);
+  packetBuffer[0] = 0b11100011;
+  packetBuffer[1] = 0;
+  packetBuffer[2] = 6;
+  packetBuffer[3] = 0xEC;
+  packetBuffer[12]  = 49;
+  packetBuffer[13]  = 0x4E;
+  packetBuffer[14]  = 49;
+  packetBuffer[15]  = 52;
+  Udp.beginPacket(timeServer, 123);
+  Udp.write(packetBuffer, NTP_PACKET_SIZE);
+  Udp.endPacket();
+}
+
+unsigned long NTPUtils::getTime() {
+
+  unsigned int localPort = 8888;
+  uint8_t packetBuffer[NTP_PACKET_SIZE];
+
+  Udp.begin(localPort);
+  sendNTPpacket(packetBuffer);
+  long start = millis();
+  while (!Udp.parsePacket() && (millis() - start < 10000))  {
+
+  }
+  if (millis() - start >= 1000) {
+    //timeout reached
+    return 0;
+  }
+  Udp.read(packetBuffer, NTP_PACKET_SIZE);
+
+  unsigned long highWord = word(packetBuffer[40], packetBuffer[41]);
+  unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]);
+  unsigned long secsSince1900 = highWord << 16 | lowWord;
+  const unsigned long seventyYears = 2208988800UL;
+  unsigned long epoch = secsSince1900 - seventyYears;
+
+  Udp.stop();
+
+  return epoch;
+}

src/utility/NTPUtils.h

@@ -0,0 +1,19 @@
+#ifndef __NTP_UTILS__
+#define __NTP_UTILS__
+
+#include "Udp.h"
+#include <time.h>
+
+class NTPUtils {
+	public:
+		NTPUtils(UDP& Udp);
+		void sendNTPpacket(uint8_t* packetBuffer);
+		unsigned long getTime();
+		static bool isTimeValid(unsigned long time);
+	private:
+		const char* timeServer = "time.apple.com";
+  		const int NTP_PACKET_SIZE = 48;
+  		UDP& Udp;
+};
+
+#endif