appendix: 23 Code-Ausschnitte aus dem Houston-Repository

Pin nixpkgs to the revision used by itc.componentware: the channel version
ships a latexminted that crashes on Python 3.14, which made every listing
fail and sent latexmk into an endless error prompt. Also force
nonstopmode/halt-on-error so a broken listing can never loop again.

figures/code/zip-download-handler.cs

@@ -0,0 +1,42 @@
+public async Task<IActionResult> OnPostDownloadZipAsync(CancellationToken cancellationToken)
+{
+    if (!OrgName.TryCreate(User.GetCompanyName(), out var orgName))
+        return NotFound();
+
+    var fallback = RedirectToPage(new
+    {
+        q = Search,
+        types = TypeFilterSelection,
+        pageSize = PageSize,
+        pageToken = PageToken,
+    });
+
+    if (SelectedDocuments is null || SelectedDocuments.Count == 0)
+        return fallback;
+
+    var relativePaths = SelectedDocuments
+        .SelectWhere<string, DocumentRelativePath>(x => new DocumentId(x).TryDecode(out var y) ? y.Value : null)
+        .Where(x => IsDownloadable(x.Name))
+        .ToList();
+
+    if (relativePaths.Count == 0)
+        return fallback;
+
+    var orgSlug = await documents.ResolveCustomerPrefixAsync(OrgId, orgName.Value, cancellationToken);
+    if (orgSlug is null)
+        return fallback;
+
+    // Zipping compresses each entry with a DeflateStream, which flushes its buffers synchronously
+    // when the entry is closed. Kestrel forbids synchronous response writes by default, so we opt
+    // in for this streamed response only. Nothing large is written synchronously - the document
+    // payloads are still copied with async IO.
+    var bodyControl = HttpContext.Features.Get<IHttpBodyControlFeature>();
+    bodyControl?.AllowSynchronousIO = true;
+
+    Response.ContentType = "application/zip";
+    Response.Headers.ContentDisposition = $"attachment; filename=\"{DocumentsService.ZipDownloadFileName}\"";
+
+    await documents.WriteZipArchiveAsync(orgSlug.Value, relativePaths, Response.Body, cancellationToken);
+
+    return new EmptyResult();
+}