Implement NTP like time sync

MediaBrowser.Api/Syncplay/SyncplayService.cs

@@ -111,14 +111,6 @@ namespace MediaBrowser.Api.Syncplay
         public double Ping { get; set; }
     }
 
-    [Route("/Syncplay/{SessionId}/GetUtcTime", "POST", Summary = "Get UtcTime")]
-    [Authenticated]
-    public class SyncplayGetUtcTime : IReturnVoid
-    {
-        [ApiMember(Name = "SessionId", IsRequired = true, DataType = "string", ParameterType = "path", Verb = "POST")]
-        public string SessionId { get; set; }
-    }
-
     /// <summary>
     /// Class SyncplayService.
     /// </summary>
@@ -129,6 +121,9 @@ namespace MediaBrowser.Api.Syncplay
         /// </summary>
         private readonly ISessionManager _sessionManager;
 
+        /// <summary>
+        /// The session context.
+        /// </summary>
         private readonly ISessionContext _sessionContext;
 
         /// <summary>
@@ -268,15 +263,5 @@ namespace MediaBrowser.Api.Syncplay
             syncplayRequest.Ping = Convert.ToInt64(request.Ping);
             _syncplayManager.HandleRequest(currentSession, syncplayRequest);
         }
-
-        /// <summary>
-        /// Handles the specified request.
-        /// </summary>
-        /// <param name="request">The request.</param>
-        /// <value>The current UTC time.</value>
-        public string Post(SyncplayGetUtcTime request)
-        {
-            return DateTime.UtcNow.ToUniversalTime().ToString("o");
-        }
     }
 }

MediaBrowser.Api/Syncplay/TimeSyncService.cs

@@ -0,0 +1,70 @@
+using System;
+using System.Collections.Generic;
+using MediaBrowser.Controller.Configuration;
+using MediaBrowser.Controller.Net;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Controller.Syncplay;
+using MediaBrowser.Model.Services;
+using MediaBrowser.Model.Syncplay;
+using Microsoft.Extensions.Logging;
+
+namespace MediaBrowser.Api.Syncplay
+{
+    [Route("/GetUtcTime", "GET", Summary = "Get UtcTime")]
+    [Authenticated]
+    public class GetUtcTime : IReturnVoid
+    {
+        // Nothing
+    }
+
+    /// <summary>
+    /// Class TimeSyncService.
+    /// </summary>
+    public class TimeSyncService : BaseApiService
+    {
+        /// <summary>
+        /// The session manager.
+        /// </summary>
+        private readonly ISessionManager _sessionManager;
+
+        /// <summary>
+        /// The session context.
+        /// </summary>
+        private readonly ISessionContext _sessionContext;
+
+        public TimeSyncService(
+            ILogger<TimeSyncService> logger,
+            IServerConfigurationManager serverConfigurationManager,
+            IHttpResultFactory httpResultFactory,
+            ISessionManager sessionManager,
+            ISessionContext sessionContext)
+            : base(logger, serverConfigurationManager, httpResultFactory)
+        {
+            _sessionManager = sessionManager;
+            _sessionContext = sessionContext;
+        }
+
+        /// <summary>
+        /// Handles the specified request.
+        /// </summary>
+        /// <param name="request">The request.</param>
+        /// <value>The current UTC time response.</value>
+        public UtcTimeResponse Get(GetUtcTime request)
+        {
+            // Important to keep the following line at the beginning
+            var requestReceptionTime = DateTime.UtcNow.ToUniversalTime().ToString("o");
+
+            var response = new UtcTimeResponse();
+            response.RequestReceptionTime = requestReceptionTime;
+            var currentSession = GetSession(_sessionContext);
+
+            // Important to keep the following two lines at the end
+            var responseTransmissionTime = DateTime.UtcNow.ToUniversalTime().ToString("o");
+            response.ResponseTransmissionTime = responseTransmissionTime;
+
+            // Implementing NTP on such a high level results in this useless 
+            // information being sent. On the other hand it enables future additions.
+            return response;
+        }
+    }
+}

MediaBrowser.Model/Syncplay/UtcTimeResponse.cs

@@ -0,0 +1,20 @@
+namespace MediaBrowser.Model.Syncplay
+{
+    /// <summary>
+    /// Class UtcTimeResponse.
+    /// </summary>
+    public class UtcTimeResponse
+    {
+        /// <summary>
+        /// Gets or sets the UTC time when request has been received.
+        /// </summary>
+        /// <value>The UTC time when request has been received.</value>
+        public string RequestReceptionTime { get; set; }
+
+        /// <summary>
+        /// Gets or sets the UTC time when response has been sent.
+        /// </summary>
+        /// <value>The UTC time when response has been sent.</value>
+        public string ResponseTransmissionTime { get; set; }
+    }
+}