Implement SignalR as middleware for project export enhancement

Backend.Tests/Controllers/LiftControllerTests.cs

@@ -5,12 +5,14 @@
 using System.Text.RegularExpressions;
 using Backend.Tests.Mocks;
 using BackendFramework.Controllers;
+using BackendFramework.Helper;
 using static BackendFramework.Helper.FileUtilities;
 using BackendFramework.Interfaces;
 using BackendFramework.Models;
 using BackendFramework.Services;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.SignalR;
 using NUnit.Framework;
 
 namespace Backend.Tests.Controllers
@@ -22,6 +24,7 @@ public class LiftControllerTests
         private IProjectService _projServ;
         private ILiftService _liftService;
         private LiftController _liftController;
+        private IHubContext<CombineHub> _notifyService;
         private IPermissionService _permissionService;
 
         [SetUp]
@@ -31,7 +34,9 @@ public void Setup()
             _projServ = new ProjectServiceMock();
             _wordrepo = new WordRepositoryMock();
             _liftService = new LiftService();
-            _liftController = new LiftController(_wordrepo, _projServ, _permissionService, _liftService);
+            _notifyService = new HubContextMock();
+            _liftController = new LiftController(
+                _wordrepo, _projServ, _permissionService, _liftService, _notifyService);
             _wordService = new WordService(_wordrepo);
         }
 
@@ -214,10 +219,6 @@ public void TestExportDeleted()
             var result = _liftController.DownloadLiftFile(proj.Id, userId).Result as FileContentResult;
             Assert.NotNull(result);
 
-            // Ensure that downloading a Lift file deletes the temporary in-memory copy.
-            var notFoundResult = _liftController.DownloadLiftFile(proj.Id, userId).Result as NotFoundObjectResult;
-            Assert.NotNull(notFoundResult);
-
             // Write LiftFile contents to a temporary directory.
             var extractedExportDir = ExtractZipFileContents(result.FileContents);
             var exportPath = Path.Combine(extractedExportDir,
@@ -228,6 +229,11 @@ public void TestExportDeleted()
             Assert.That(Regex.Matches(text, "<entry").Count, Is.EqualTo(3));
             // There is only one deleted word
             Assert.That(text.IndexOf("dateDeleted"), Is.EqualTo(text.LastIndexOf("dateDeleted")));
+
+            // Delete the export
+            _liftController.DeleteLiftFile(userId);
+            var notFoundResult = _liftController.DownloadLiftFile(proj.Id, userId).Result as NotFoundObjectResult;
+            Assert.NotNull(notFoundResult);
         }
 
         [Test]

Backend.Tests/Mocks/HubContextMock.cs

@@ -0,0 +1,74 @@
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using BackendFramework.Helper;
+using Microsoft.AspNetCore.SignalR;
+
+namespace Backend.Tests.Mocks
+{
+    /// <summary>
+    /// A *very* sparse, mostly unimplemented Mock of SignalR HubContext.
+    /// </summary>
+    public class HubContextMock : IHubContext<CombineHub>
+    {
+        public IHubClients Clients => new HubClientsMock();
+
+        public IGroupManager Groups => throw new System.NotImplementedException();
+    }
+
+    public class HubClientsMock : IHubClients
+    {
+        public IClientProxy AllExcept(IReadOnlyList<string> excludedConnectionIds)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public IClientProxy Client(string connectionId)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public IClientProxy Clients(IReadOnlyList<string> connectionIds)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public IClientProxy Group(string groupName)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public IClientProxy GroupExcept(string groupName, IReadOnlyList<string> excludedConnectionIds)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public IClientProxy Groups(IReadOnlyList<string> groupNames)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public IClientProxy User(string userId)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public IClientProxy Users(IReadOnlyList<string> userIds)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public IClientProxy All => new ClientProxyMock();
+    }
+
+    public class ClientProxyMock : IClientProxy
+    {
+        // Disable this warning as this mock simply needs to return an empty Task, not await anything.
+#pragma warning disable 1998
+        public async Task SendCoreAsync(
+#pragma warning restore 1998
+            string method, object[] args, CancellationToken cancellationToken = new CancellationToken())
+        {
+        }
+    }
+}

Backend/BackendFramework.csproj

@@ -6,20 +6,20 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
-    <None Remove="Data\sdList.txt"/>
+    <None Remove="Data\sdList.txt" />
   </ItemGroup>
   <ItemGroup>
-    <EmbeddedResource Include="Data\sdList.txt"/>
+    <EmbeddedResource Include="Data\sdList.txt" />
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="3.1.5" />
     <PackageReference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" Version="3.1.5" />
     <PackageReference Include="icu.net" Version="2.6.0" />
-    <PackageReference Include="Icu4c.Win.Full.Lib" Version="62.1.4-beta"/>
+    <PackageReference Include="Icu4c.Win.Full.Lib" Version="62.1.4-beta" />
     <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="6.7.1" />
     <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="6.7.1" />
     <PackageReference Include="MongoDB.Driver" Version="2.10.4" />
-    <PackageReference Include="SIL.Core" Version="7.0.0-alpha0822"/>
+    <PackageReference Include="SIL.Core" Version="7.0.0-alpha0822" />
     <PackageReference Include="SIL.Core.Desktop" Version="7.0.0-alpha0822">
       <NoWarn>NU1701</NoWarn>
     </PackageReference>
@@ -29,8 +29,8 @@
     <PackageReference Include="SIL.Lift" Version="7.0.0-alpha0822">
       <NoWarn>NU1701</NoWarn>
     </PackageReference>
-    <PackageReference Include="SIL.WritingSystems" Version="7.0.0-alpha0822"/>
-    <PackageReference Include="MailKit" Version="2.7.0"/>
-    <PackageReference Include="Microsoft.AspNetCore.Mvc.WebApiCompatShim" Version="2.2.0"/>
+    <PackageReference Include="SIL.WritingSystems" Version="7.0.0-alpha0822" />
+    <PackageReference Include="MailKit" Version="2.7.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.WebApiCompatShim" Version="2.2.0" />
   </ItemGroup>
 </Project>

Backend/Controllers/LiftController.cs

@@ -3,11 +3,13 @@
 using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
+using BackendFramework.Helper;
 using BackendFramework.Interfaces;
 using BackendFramework.Models;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Cors;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.SignalR;
 using SIL.Lift.Parsing;
 using static BackendFramework.Helper.FileUtilities;
 
@@ -24,14 +26,16 @@ public class LiftController : Controller
         private readonly ILiftService _liftService;
         private readonly IProjectService _projectService;
         private readonly IPermissionService _permissionService;
+        private readonly IHubContext<CombineHub> _notifyService;
 
         public LiftController(IWordRepository repo, IProjectService projServ, IPermissionService permissionService,
-            ILiftService liftService)
+            ILiftService liftService, IHubContext<CombineHub> notifyService)
         {
             _wordRepo = repo;
             _projectService = projServ;
             _liftService = liftService;
             _permissionService = permissionService;
+            _notifyService = notifyService;
         }
 
         /// <summary> Adds data from a zipped directory containing a lift file </summary>
@@ -186,7 +190,8 @@ public async Task<IActionResult> ExportLiftFile(string projectId)
             return await ExportLiftFile(projectId, userId);
         }
 
-        public async Task<IActionResult> ExportLiftFile(string projectId, string userId)
+        // These internal methods are extracted for unit testing
+        internal async Task<IActionResult> ExportLiftFile(string projectId, string userId)
         {
             if (!_permissionService.HasProjectPermission(HttpContext, Permission.ImportExport))
             {
@@ -199,24 +204,51 @@ public async Task<IActionResult> ExportLiftFile(string projectId, string userId)
                 return new UnsupportedMediaTypeResult();
             }
 
-            // Ensure project exists and has words
+            // Ensure project exists
             var proj = _projectService.GetProject(projectId);
             if (proj is null)
             {
                 return new NotFoundObjectResult(projectId);
             }
-            var words = await _wordRepo.GetAllWords(projectId);
-            if (words.Count == 0)
+
+            // Check if another export started
+            if (_liftService.IsExportInProgress(userId))
             {
-                return new BadRequestResult();
+                return new ConflictResult();
             }
 
-            // Export the data to a zip, read into memory, and delete zip
-            var exportedFilepath = CreateLiftExport(projectId);
+            // Store in-progress status for the export
+            _liftService.SetExportInProgress(userId, true);
 
-            // Store the temporary path to the exported file for user to download later.
-            _liftService.StoreExport(userId, exportedFilepath);
-            return new OkObjectResult(projectId);
+            try
+            {
+                // Ensure project has words
+                var words = await _wordRepo.GetAllWords(projectId);
+                if (words.Count == 0)
+                {
+                    _liftService.SetExportInProgress(userId, false);
+                    return new BadRequestResult();
+                }
+
+                // Export the data to a zip, read into memory, and delete zip
+                var exportedFilepath = CreateLiftExport(projectId);
+
+                // Store the temporary path to the exported file for user to download later.
+                _liftService.StoreExport(userId, exportedFilepath);
+                await _notifyService.Clients.All.SendAsync("DownloadReady", userId);
+                return new OkObjectResult(projectId);
+            }
+            catch
+            {
+                _liftService.SetExportInProgress(userId, false);
+                throw;
+            }
+        }
+
+        internal string CreateLiftExport(string projectId)
+        {
+            var exportedFilepath = _liftService.LiftExport(projectId, _wordRepo, _projectService);
+            return exportedFilepath;
         }
 
         /// <summary> Downloads project data in zip file </summary>
@@ -229,7 +261,7 @@ public async Task<IActionResult> DownloadLiftFile(string projectId)
             return await DownloadLiftFile(projectId, userId);
         }
 
-        public async Task<IActionResult> DownloadLiftFile(string projectId, string userId)
+        internal async Task<IActionResult> DownloadLiftFile(string projectId, string userId)
         {
             if (!_permissionService.HasProjectPermission(HttpContext, Permission.ImportExport))
             {
@@ -244,18 +276,31 @@ public async Task<IActionResult> DownloadLiftFile(string projectId, string userI
             }
 
             var file = await System.IO.File.ReadAllBytesAsync(filePath);
-            _liftService.DeleteExport(userId);
             return File(
                 file,
                 "application/zip",
                 $"LiftExport-{projectId}-{DateTime.Now:yyyy-MM-dd_hh-mm-ss-fff}.zip");
         }
 
-        // This method is extracted so that it can be unit tested
-        internal string CreateLiftExport(string projectId)
+        /// <summary> Delete prepared export </summary>
+        /// <remarks> GET: v1/projects/{projectId}/words/deleteexport </remarks>
+        /// <returns> UserId, if successful </returns>
+        [HttpGet("deleteexport")]
+        public IActionResult DeleteLiftFile()
         {
-            var exportedFilepath = _liftService.LiftExport(projectId, _wordRepo, _projectService);
-            return exportedFilepath;
+            var userId = _permissionService.GetUserId(HttpContext);
+            return DeleteLiftFile(userId);
+        }
+
+        internal IActionResult DeleteLiftFile(string userId)
+        {
+            if (!_permissionService.HasProjectPermission(HttpContext, Permission.ImportExport))
+            {
+                return new ForbidResult();
+            }
+
+            _liftService.DeleteExport(userId);
+            return new OkObjectResult(userId);
         }
     }
 

Backend/Helper/CombineHub.cs

@@ -0,0 +1,8 @@
+using Microsoft.AspNetCore.SignalR;
+
+namespace BackendFramework.Helper
+{
+    public class CombineHub : Hub
+    {
+    }
+}

Backend/Interfaces/ILiftService.cs

@@ -14,5 +14,7 @@ ILexiconMerger<LiftObject, LiftEntry, LiftSense, LiftExample> GetLiftImporterExp
         void StoreExport(string key, string filePath);
         string? RetrieveExport(string key);
         bool DeleteExport(string key);
+        void SetExportInProgress(string key, bool isInProgress);
+        bool IsExportInProgress(string key);
     }
 }