DateTimeNist.cs

DateTimeNist.cs

using System;
using System.Net;
using System.Net.Cache;
using System.IO;
using System.Text.RegularExpressions;

public class DateTimeNist
{
    public static DateTime Now
    {
        get{
            //エラーが起きた場合はDateTime.MinValueが帰る
            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
            request.Timeout = 5 * 1000;

            try {
                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 ();
                }
            }
            catch(System.Net.WebException ex) {
                //HTTPプロトコルエラーかどうか調べる
                if (ex.Status == System.Net.WebExceptionStatus.ProtocolError) {
                    //HttpWebResponseを取得
                    System.Net.HttpWebResponse errres = (System.Net.HttpWebResponse)ex.Response;
                    //応答したURIを表示する
                    Debug.Log ("errres.ResponseUri" + errres.ResponseUri);
                    //応答ステータスコードを表示する
                    Debug.Log (errres.StatusCode + ":" + errres.StatusDescription);
                } else {
                    Debug.Log ("errres.ResponseUri" + ex.Message);
                }
            }

            return dateTime;
        }
    }
}