How to get DateTime from the internet?
For environments where port 13 is blocked, time from NIST can be web scraped as below,
public static DateTime GetNistTime()
{
DateTime dateTime = DateTime.MinValue;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://nist.time.gov/actualtime.cgi?lzbc=siqm9b");
request.Method = "GET";
request.Accept = "text/html, application/xhtml+xml, */*";
request.UserAgent = "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; Trident/6.0)";
request.ContentType = "application/x-www-form-urlencoded";
request.CachePolicy = new RequestCachePolicy(RequestCacheLevel.NoCacheNoStore); //No caching
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
if (response.StatusCode == HttpStatusCode.OK)
{
StreamReader stream = new StreamReader(response.GetResponseStream());
string html = stream.ReadToEnd();//<timestamp time=\"1395772696469995\" delay=\"1395772696469995\"/>
string time = Regex.Match(html, @"(?<=\btime="")[^""]*").Value;
double milliseconds = Convert.ToInt64(time) / 1000.0;
dateTime = new DateTime(1970, 1, 1).AddMilliseconds(milliseconds).ToLocalTime();
}
return dateTime;
}
Here is code sample that you can use to retrieve time from NIST Internet Time Service
var client = new TcpClient("time.nist.gov", 13);
using (var streamReader = new StreamReader(client.GetStream()))
{
var response = streamReader.ReadToEnd();
var utcDateTimeString = response.Substring(7, 17);
var localDateTime = DateTime.ParseExact(utcDateTimeString, "yy-MM-dd HH:mm:ss", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal);
}