5 files changed, 156 insertions, 71 deletions
diff --git a/BackEnd/Timeline/Controllers/TimelinePostController.cs b/BackEnd/Timeline/Controllers/TimelinePostController.cs
index da45cbea..f00a689c 100644
--- a/BackEnd/Timeline/Controllers/TimelinePostController.cs
+++ b/BackEnd/Timeline/Controllers/TimelinePostController.cs
@@ -1,6 +1,8 @@
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.Extensions.Logging;
 using System;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
@@ -13,6 +15,7 @@ using Timeline.Models.Validation;
 using Timeline.Services.Mapper;
 using Timeline.Services.Timeline;
 using Timeline.Services.User;
+using Timeline.SignalRHub;
 
 namespace Timeline.Controllers
 {
@@ -24,6 +27,8 @@ namespace Timeline.Controllers
     [ProducesErrorResponseType(typeof(CommonResponse))]
     public class TimelinePostController : MyControllerBase
     {
+        private readonly ILogger<TimelinePostController> _logger;
+
         private readonly ITimelineService _timelineService;
         private readonly ITimelinePostService _postService;
 
@@ -31,12 +36,16 @@ namespace Timeline.Controllers
 
         private readonly MarkdownProcessor _markdownProcessor;
 
-        public TimelinePostController(ITimelineService timelineService, ITimelinePostService timelinePostService, IGenericMapper mapper, MarkdownProcessor markdownProcessor)
+        private readonly IHubContext<TimelineHub> _timelineHubContext;
+
+        public TimelinePostController(ILogger<TimelinePostController> logger, ITimelineService timelineService, ITimelinePostService timelinePostService, IGenericMapper mapper, MarkdownProcessor markdownProcessor, IHubContext<TimelineHub> timelineHubContext)
         {
+            _logger = logger;
             _timelineService = timelineService;
             _postService = timelinePostService;
             _mapper = mapper;
             _markdownProcessor = markdownProcessor;
+            _timelineHubContext = timelineHubContext;
         }
 
         private bool UserHasAllTimelineManagementPermission => UserHasPermission(UserPermission.AllTimelineManagement);
@@ -207,6 +216,11 @@ namespace Timeline.Controllers
             try
             {
                 var post = await _postService.CreatePostAsync(timelineId, userId, createRequest);
+
+                var group = TimelineHub.GenerateTimelinePostChangeListeningGroupName(timeline);
+                await _timelineHubContext.Clients.Group(group).SendAsync(nameof(ITimelineClient.OnTimelinePostChanged), timeline);
+                _logger.LogInformation("Notify group {0} of timeline post change.", group);
+
                 var result = await Map(post);
                 return result;
             }
diff --git a/BackEnd/Timeline/SignalRHub/ITimelineClient.cs b/BackEnd/Timeline/SignalRHub/ITimelineClient.cs
new file mode 100644
index 00000000..0d1be093
--- /dev/null
+++ b/BackEnd/Timeline/SignalRHub/ITimelineClient.cs
@@ -0,0 +1,9 @@
+using System.Threading.Tasks;
+
+namespace Timeline.SignalRHub
+{
+    public interface ITimelineClient
+    {
+        Task OnTimelinePostChanged(string timelineName);
+    }
+}
diff --git a/BackEnd/Timeline/SignalRHub/TimelineHub.cs b/BackEnd/Timeline/SignalRHub/TimelineHub.cs
new file mode 100644
index 00000000..2ad7bd66
--- /dev/null
+++ b/BackEnd/Timeline/SignalRHub/TimelineHub.cs
@@ -0,0 +1,58 @@
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Threading.Tasks;
+using Timeline.Auth;
+using Timeline.Services;
+using Timeline.Services.Timeline;
+using Timeline.Services.User;
+
+namespace Timeline.SignalRHub
+{
+    public class TimelineHub : Hub<ITimelineClient>
+    {
+        private readonly ILogger<TimelineHub> _logger;
+        private readonly ITimelineService _timelineService;
+
+        public TimelineHub(ILogger<TimelineHub> logger, ITimelineService timelineService)
+        {
+            _logger = logger;
+            _timelineService = timelineService;
+        }
+
+        public static string GenerateTimelinePostChangeListeningGroupName(string timelineName)
+        {
+            return $"timeline-post-change-{timelineName}";
+        }
+
+        public async Task SubscribeTimelinePostChange(string timelineName)
+        {
+            try
+            {
+                var timelineId = await _timelineService.GetTimelineIdByNameAsync(timelineName);
+                var user = Context.User;
+                if (!user.HasPermission(UserPermission.AllTimelineManagement) && !await _timelineService.HasReadPermissionAsync(timelineId, user.GetOptionalUserId()))
+                    throw new HubException("Forbidden.");
+
+                var group = GenerateTimelinePostChangeListeningGroupName(timelineName);
+                await Groups.AddToGroupAsync(Context.ConnectionId, group);
+                _logger.LogInformation("Add connection {0} to group {1}", Context.ConnectionId, group);
+            }
+            catch (ArgumentException)
+            {
+                throw new HubException("Timeline name is illegal.");
+            }
+            catch (EntityNotExistException)
+            {
+                throw new HubException("Timeline not exist.");
+            }
+        }
+
+        public async Task UnsubscribeTimelinePostChange(string timelineName)
+        {
+            var group = GenerateTimelinePostChangeListeningGroupName(timelineName);
+            await Groups.RemoveFromGroupAsync(Context.ConnectionId, group);
+            _logger.LogInformation("Remove connection {0} from group {1}", Context.ConnectionId, group);
+        }
+    }
+}
diff --git a/BackEnd/Timeline/Startup.cs b/BackEnd/Timeline/Startup.cs
index 1e0d4779..18097e2c 100644
--- a/BackEnd/Timeline/Startup.cs
+++ b/BackEnd/Timeline/Startup.cs
@@ -26,6 +26,7 @@ using Timeline.Services.Mapper;
 using Timeline.Services.Timeline;
 using Timeline.Services.Token;
 using Timeline.Services.User;
+using Timeline.SignalRHub;
 using Timeline.Swagger;
 
 namespace Timeline
@@ -85,6 +86,8 @@ namespace Timeline
                 options.InvalidModelStateResponseFactory = InvalidModelResponseFactory.Factory;
             });
 
+            services.AddSignalR();
+
             services.AddAuthentication(AuthenticationConstants.Scheme)
                 .AddScheme<MyAuthenticationOptions, MyAuthenticationHandler>(AuthenticationConstants.Scheme, AuthenticationConstants.DisplayName, o => { });
             services.AddAuthorization();
@@ -154,6 +157,7 @@ namespace Timeline
             app.UseEndpoints(endpoints =>
             {
                 endpoints.MapControllers();
+                endpoints.MapHub<TimelineHub>("api/hub/timeline");
             });
 
             UnknownEndpointMiddleware.Attach(app);
diff --git a/BackEnd/Timeline/Timeline.csproj b/BackEnd/Timeline/Timeline.csproj
index b9653b25..955947af 100644
--- a/BackEnd/Timeline/Timeline.csproj
+++ b/BackEnd/Timeline/Timeline.csproj
@@ -49,19 +49,19 @@
 
     <ItemGroup>
         <Compile Update="Auth\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Controllers\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Filters\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Models\Http\Resource.Designer.cs">
             <DesignTime>True</DesignTime>
@@ -69,122 +69,122 @@
             <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Models\Validation\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Routes\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Services\DatabaseManagement\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Services\Data\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Services\Imaging\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Services\Mapper\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Services\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Services\Timeline\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Services\Token\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Services\User\Avatar\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
         <Compile Update="Services\User\Resource.Designer.cs">
-          <DesignTime>True</DesignTime>
-          <AutoGen>True</AutoGen>
-          <DependentUpon>Resource.resx</DependentUpon>
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Resource.resx</DependentUpon>
         </Compile>
     </ItemGroup>
 
     <ItemGroup>
         <EmbeddedResource Update="Auth\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Controllers\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Filters\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Models\Http\Resource.resx">
             <Generator>ResXFileCodeGenerator</Generator>
             <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Models\Validation\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Routes\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Services\DatabaseManagement\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Services\Data\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Services\Imaging\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Services\Mapper\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Services\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Services\Timeline\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Services\Token\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Services\User\Avatar\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Services\User\Resource.resx">
-          <Generator>ResXFileCodeGenerator</Generator>
-          <LastGenOutput>Resource.Designer.cs</LastGenOutput>
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Resource.Designer.cs</LastGenOutput>
         </EmbeddedResource>
     </ItemGroup>
 </Project>
 \ No newline at end of file