refactor ProjectController to use FileCallbackResult instead of my ha…

…cked version

backend/LexBoxApi/Controllers/ActionResults/FileCallbackResult.cs

@@ -0,0 +1,50 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
+
+namespace LexBoxApi.Controllers.ActionResults;
+
+/// <summary>
+/// Represents an <see cref="ActionResult"/> that when executed will
+/// execute a callback to write the file content out as a stream.
+/// copied from https://github.com/StephenClearyExamples/AsyncDynamicZip/tree/net6-ziparchive
+/// MIT License
+/// </summary>
+public sealed class FileCallbackResult : FileResult
+{
+    private readonly Func<Stream, ActionContext, Task> _callback;
+
+    /// <summary>
+    /// Creates a new <see cref="FileCallbackResult"/> instance.
+    /// </summary>
+    /// <param name="contentType">The Content-Type header of the response.</param>
+    /// <param name="callback">The stream with the file.</param>
+    public FileCallbackResult(string contentType, Func<Stream, ActionContext, Task> callback)
+        : base(contentType)
+    {
+        _ = callback ?? throw new ArgumentNullException(nameof(callback));
+        _callback = callback;
+    }
+
+    /// <inheritdoc />
+    public override Task ExecuteResultAsync(ActionContext context)
+    {
+        _ = context ?? throw new ArgumentNullException(nameof(context));
+        var executor =
+            new FileCallbackResultExecutor(context.HttpContext.RequestServices.GetRequiredService<ILoggerFactory>());
+        return executor.ExecuteAsync(context, this);
+    }
+
+    private sealed class FileCallbackResultExecutor : FileResultExecutorBase
+    {
+        public FileCallbackResultExecutor(ILoggerFactory loggerFactory)
+            : base(CreateLogger<FileCallbackResultExecutor>(loggerFactory))
+        {
+        }
+
+        public Task ExecuteAsync(ActionContext context, FileCallbackResult result)
+        {
+            SetHeadersAndLog(context, result, fileLength: null, enableRangeProcessing: false);
+            return result._callback(context.HttpContext.Response.BodyWriter.AsStream(), context);
+        }
+    }
+}

backend/LexBoxApi/Controllers/ProjectController.cs

@@ -1,6 +1,7 @@
 using System.Collections.Generic;
 using LexBoxApi.Auth;
 using LexBoxApi.Auth.Attributes;
+using LexBoxApi.Controllers.ActionResults;
 using LexBoxApi.Jobs;
 using LexBoxApi.Services;
 using LexCore.Entities;
@@ -114,18 +115,11 @@ public async Task<IActionResult> BackupProject(string code)
         var backupExecutor = await projectService.BackupProject(code);
         if (backupExecutor is null)
             return NotFound();
-        return new StreamingResponse(backupExecutor.ExecuteBackup, "application/zip", $"{code}_backup.zip");
-    }
-
-    private class StreamingResponse(Func<Stream, Task> execute, string contentType, string fileName): ActionResult
-    {
-        public override async Task ExecuteResultAsync(ActionContext context)
+        return new FileCallbackResult("application/zip",
+            async (stream, context) => await backupExecutor.ExecuteBackup(stream, context.HttpContext.RequestAborted))
         {
-            context.HttpContext.Response.ContentType = contentType;
-            context.HttpContext.Response.Headers.Append("Content-Disposition",
-                $"attachment; filename=\"{Path.GetFileName(fileName)}\"");
-            await execute.Invoke(context.HttpContext.Response.BodyWriter.AsStream());
-        }
+            FileDownloadName = $"{code}_backup.zip"
+        };
     }
 
     [HttpPost("resetProject/{code}")]

backend/LexBoxApi/Services/HgService.cs

@@ -89,10 +89,10 @@ public async Task DeleteRepo(string code)
         {
             return null;
         }
-        return new(stream => Task.Run(() =>
+        return new((stream, token) => Task.Run(() =>
         {
             ZipFile.CreateFromDirectory(repoPath, stream, CompressionLevel.Fastest, false);
-        }));
+        }, token));
     }
 
     public async Task ResetRepo(string code)

backend/LexCore/ServiceInterfaces/IHgService.cs

@@ -2,7 +2,7 @@
 
 namespace LexCore.ServiceInterfaces;
 
-public record BackupExecutor(Func<Stream, Task> ExecuteBackup);
+public record BackupExecutor(Func<Stream, CancellationToken, Task> ExecuteBackup);
 public interface IHgService
 {
     Task InitRepo(string code);