fix: serve downloads only on the site host and select the clicked Quest build

Review follow-ups:
- The downloads routes now answer only on the apex (the site's host) and 404
  on every other accepted host, so the game's open API/CDN subdomains can't
  serve the builds.
- Install on Quest passes its own file to the Quest page instead of always
  picking the newest release.
- Waiting for the bucket's headers is limited to 30 s; the body still streams
  without a limit.
- Dispose the upstream request message; use LINQ in FindFile.

DorkNet.Server.Tests/DownloadsControllerTests.cs

@@ -11,11 +11,13 @@ using Microsoft.Extensions.Logging.Abstractions;
 
 namespace DorkNet.Server.Tests;
 
-/// <summary>The site's downloads proxy: off without config, serves only files
-/// the manifest lists, and passes Range through so the browser Quest installer
-/// can read an .xapk in place.</summary>
+/// <summary>The site's downloads proxy: off without config, only on the site's
+/// own host, serves only files the manifest lists, and passes Range through so
+/// the browser Quest installer can read an .xapk in place.</summary>
 public sealed class DownloadsControllerTests
 {
+    private const string Apex = "dorknet.example.com";
+
     private const string Manifest = """
         {"releases":[{"id":"2023.03","title":"March 2023","files":[
           {"id":"quest","platform":"quest","name":"DorkNet-2023.03-Quest.xapk","path":"2023.03/DorkNet-2023.03-Quest.xapk","size":10,"sha256":"x"}]}]}
@@ -29,6 +31,19 @@ public sealed class DownloadsControllerTests
         Assert.IsType<NotFoundObjectResult>(await controller.GetManifest(CancellationToken.None));
     }
 
+    [Theory]
+    [InlineData("api.dorknet.example.com")]
+    [InlineData("cdn.dorknet.example.com")]
+    public async Task Other_hosts_get_404_without_touching_the_bucket(string host)
+    {
+        var (controller, ctx) = Create("http://bucket.internal:3902", _ => throw new InvalidOperationException("no request expected"));
+        ctx.Request.Host = new HostString(host);
+
+        Assert.IsType<NotFoundObjectResult>(await controller.GetManifest(CancellationToken.None));
+        await controller.GetFile("2023.03/DorkNet-2023.03-Quest.xapk", CancellationToken.None);
+        Assert.Equal(StatusCodes.Status404NotFound, ctx.Response.StatusCode);
+    }
+
     [Fact]
     public void Only_listed_paths_are_found()
     {
@@ -91,8 +106,12 @@ public sealed class DownloadsControllerTests
         }).Build();
         var service = new DownloadsService(config, new StubFactory(handler), NullLogger<DownloadsService>.Instance);
         var ctx = new DefaultHttpContext();
+        ctx.Request.Host = new HostString(Apex);
         ctx.Response.Body = new MemoryStream();
-        var controller = new DownloadsController(service) { ControllerContext = new ControllerContext { HttpContext = ctx } };
+        var controller = new DownloadsController(service, new DomainConfig(Apex))
+        {
+            ControllerContext = new ControllerContext { HttpContext = ctx },
+        };
         return (controller, ctx);
     }
 

DorkNet.Server/Controllers/Site/DownloadsController.cs

@@ -11,20 +11,26 @@ namespace DorkNet.Server.Controllers.Site;
 /// installer can read an .xapk's zip directory and entries without fetching
 /// the whole file. Only files the manifest lists are served.
 ///
-/// The builds contain Rec Room's own game files: put the site behind an
-/// access proxy (e.g. Cloudflare Access) before turning this on.
+/// The builds contain Rec Room's own game files, so the routes answer only on
+/// the site's own host (the apex) and 404 on every other host the server
+/// accepts: the game's API/CDN subdomains are typically left open for the
+/// client, while the site sits behind an access proxy (e.g. Cloudflare Access).
 /// </summary>
 [ApiController]
 [AllowAnonymous]
 [Route("api/site/v1/downloads")]
-public class DownloadsController(DownloadsService downloads) : ControllerBase
+public class DownloadsController(DownloadsService downloads, DomainConfig domain) : ControllerBase
 {
+    private bool Available => downloads.IsConfigured
+        && string.Equals(Request.Host.Host, domain.Apex, StringComparison.OrdinalIgnoreCase);
+
     /// <summary>GET /api/site/v1/downloads — the manifest as published
-    /// (snake_case keys), or 404 when downloads aren't set up.</summary>
+    /// (snake_case keys), or 404 when downloads aren't set up or the request
+    /// isn't for the site's host.</summary>
     [HttpGet]
     public async Task<IActionResult> GetManifest(CancellationToken ct)
     {
-        if (!downloads.IsConfigured) return NotFound(new { error = "Downloads aren't set up on this server." });
+        if (!Available) return NotFound(new { error = "Downloads aren't set up on this server." });
         var manifest = await downloads.GetManifestAsync(ct);
         Response.Headers.CacheControl = "no-cache";
         return Content((manifest ?? new System.Text.Json.Nodes.JsonObject { ["releases"] = new System.Text.Json.Nodes.JsonArray() })
@@ -36,7 +42,7 @@ public class DownloadsController(DownloadsService downloads) : ControllerBase
     [HttpGet("files/{**path}")]
     public async Task GetFile(string path, CancellationToken ct)
     {
-        if (!downloads.IsConfigured) { Response.StatusCode = StatusCodes.Status404NotFound; return; }
+        if (!Available) { Response.StatusCode = StatusCodes.Status404NotFound; return; }
         var manifest = await downloads.GetManifestAsync(ct);
         var entry = manifest is null ? null : DownloadsService.FindFile(manifest, path);
         if (entry is null) { Response.StatusCode = StatusCodes.Status404NotFound; return; }

DorkNet.Server/Services/DownloadsService.cs

@@ -20,6 +20,10 @@ public sealed class DownloadsService
 {
     public const string HttpClientName = "downloads";
 
+    // How long the bucket may take to start answering. The body then streams
+    // with no limit (the client has none; the caller's abort token ends it).
+    private static readonly TimeSpan HeaderTimeout = TimeSpan.FromSeconds(30);
+
     private readonly IHttpClientFactory _httpClientFactory;
     private readonly Uri? _baseUri;
     private readonly string? _host;
@@ -58,15 +62,9 @@ public sealed class DownloadsService
     public static JsonObject? FindFile(JsonObject manifest, string path)
     {
         if (manifest["releases"] is not JsonArray releases) return null;
-        foreach (var release in releases.OfType<JsonObject>())
-        {
-            if (release["files"] is not JsonArray files) continue;
-            foreach (var file in files.OfType<JsonObject>())
-            {
-                if (string.Equals((string?)file["path"], path, StringComparison.Ordinal)) return file;
-            }
-        }
-        return null;
+        return releases.OfType<JsonObject>()
+            .SelectMany(r => r["files"] is JsonArray files ? files.OfType<JsonObject>() : [])
+            .FirstOrDefault(f => string.Equals((string?)f["path"], path, StringComparison.Ordinal));
     }
 
     /// <summary>GET a file, forwarding the caller's Range header. The caller
@@ -78,10 +76,22 @@ public sealed class DownloadsService
     {
         if (_baseUri is null) throw new InvalidOperationException("Downloads are not configured.");
         var url = new Uri(_baseUri, string.Join('/', path.Split('/').Select(Uri.EscapeDataString)));
-        var req = new HttpRequestMessage(HttpMethod.Get, url);
+        using var req = new HttpRequestMessage(HttpMethod.Get, url);
         if (_host is not null) req.Headers.Host = _host;
         if (!string.IsNullOrEmpty(range) && RangeHeaderValue.TryParse(range, out var r)) req.Headers.Range = r;
         var client = _httpClientFactory.CreateClient(HttpClientName);
-        return await client.SendAsync(req, HttpCompletionOption.ResponseHeadersRead, ct);
+        // The timeout covers only getting the headers: with ResponseHeadersRead
+        // the token is released once they arrive, and disposing the source
+        // here stops its timer before the body is streamed.
+        using var headers = CancellationTokenSource.CreateLinkedTokenSource(ct);
+        headers.CancelAfter(HeaderTimeout);
+        try
+        {
+            return await client.SendAsync(req, HttpCompletionOption.ResponseHeadersRead, headers.Token);
+        }
+        catch (OperationCanceledException) when (!ct.IsCancellationRequested)
+        {
+            throw new TimeoutException($"The downloads bucket didn't answer within {HeaderTimeout.TotalSeconds:0} s.");
+        }
     }
 }

DorkNet.Server/Startup/ServiceCollectionExtensions.cs

@@ -219,8 +219,9 @@ public static class ServiceCollectionExtensions
         services.AddHostedService<TestCaseIssueReconciler>();
         // CI-published client builds for the site's Downloads / Quest pages.
         // Off (IsConfigured=false) without DorkNet:Downloads:BaseUrl. No client
-        // timeout: a multi-GB file streams for longer than the default 100 s;
-        // the request's own abort token still ends it.
+        // timeout: a multi-GB file streams for longer than the default 100 s.
+        // DownloadsService limits the wait for headers itself, and the
+        // request's own abort token ends the stream.
         services.AddHttpClient(DownloadsService.HttpClientName, c => c.Timeout = Timeout.InfiniteTimeSpan);
         services.AddSingleton<DownloadsService>();
         // Scoped (per-request) — these services hold DbContext references and

DorkNet.Server/site/src/lib/downloads.ts

@@ -46,10 +46,13 @@ export function getDownloads(fresh = false): Promise<DownloadsManifest | null> {
 export const fileUrl = (f: DownloadFile) =>
   `/api/site/v1/downloads/files/${f.path.split('/').map(encodeURIComponent).join('/')}`;
 
-/** The newest release's Quest package, if one is published. */
-export function latestQuest(m: DownloadsManifest | null): { release: DownloadRelease; file: DownloadFile } | null {
+export interface QuestBuild { release: DownloadRelease; file: DownloadFile }
+
+/** A published Quest package: the one at `path` when given, otherwise the
+ * newest release's. Null when there's no match. */
+export function questBuild(m: DownloadsManifest | null, path?: string | null): QuestBuild | null {
   for (const release of m?.releases ?? []) {
-    const file = release.files.find((f) => f.id === 'quest');
+    const file = release.files.find((f) => f.id === 'quest' && (!path || f.path === path));
     if (file) return { release, file };
   }
   return null;

DorkNet.Server/site/src/pages/Downloads.tsx

@@ -73,7 +73,7 @@ function FileCard({ f, rel }: { f: DownloadFile; rel: DownloadRelease }) {
       <div className="mt-auto flex flex-wrap items-center gap-2 pt-1">
         {f.id === 'quest' ? (
           <>
-            <Link className="btn-primary" to="/quest?build=latest">Install on Quest</Link>
+            <Link className="btn-primary" to={`/quest?file=${encodeURIComponent(f.path)}`}>Install on Quest</Link>
             <a className="btn-secondary" href={fileUrl(f)} download={f.name}>Download</a>
           </>
         ) : (

DorkNet.Server/site/src/pages/Quest.tsx

@@ -2,7 +2,7 @@ import { useEffect, useRef, useState } from 'react';
 import { useSearchParams } from 'react-router';
 import { fileSource, openXapk, urlSource, type Xapk } from '../lib/xapk';
 import { connectHeadset, installXapk, webUsbSupported, type Headset, type Progress } from '../lib/questInstall';
-import { fileUrl, getDownloads, latestQuest } from '../lib/downloads';
+import { fileUrl, getDownloads, questBuild, type QuestBuild } from '../lib/downloads';
 
 const fmtSize = (n: number) =>
   n >= 1e9 ? `${(n / 1e9).toFixed(2)} GB` : n >= 1e6 ? `${(n / 1e6).toFixed(1)} MB` : `${Math.max(1, Math.round(n / 1e3))} KB`;
@@ -46,7 +46,7 @@ export function Quest() {
   const [done, setDone] = useState(false);
   const fileRef = useRef<HTMLInputElement>(null);
   // The server's latest published Quest build, if it offers downloads.
-  const [latest, setLatest] = useState<ReturnType<typeof latestQuest>>(null);
+  const [latest, setLatest] = useState<QuestBuild | null>(null);
   const [params] = useSearchParams();
 
   const open = async (load: () => Promise<Xapk>) => {
@@ -60,16 +60,17 @@ export function Quest() {
     if (f) await open(() => openXapk(fileSource(f)));
   };
 
-  const pickLatest = async (l = latest) => {
-    if (l) await open(() => openXapk(urlSource(fileUrl(l.file), l.file.name, l.file.size)));
+  const pickBuild = async (b: QuestBuild | null) => {
+    if (b) await open(() => openXapk(urlSource(fileUrl(b.file), b.file.name, b.file.size)));
   };
 
   useEffect(() => {
     getDownloads().then((m) => {
-      const l = latestQuest(m);
-      setLatest(l);
-      // Arriving from the Downloads page's "Install on Quest".
-      if (l && params.get('build') === 'latest') void pickLatest(l);
+      setLatest(questBuild(m));
+      // Arriving from a Quest card's "Install on Quest" on the Downloads page:
+      // that card's own file, which may not be the newest release's.
+      const wanted = params.get('file');
+      if (wanted) void pickBuild(questBuild(m, wanted));
     }).catch(() => { /* no downloads: only the file picker */ });
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, []);
@@ -142,7 +143,7 @@ export function Quest() {
         <input ref={fileRef} type="file" accept=".xapk,.zip" className="hidden" onChange={(e) => pickFile(e.target.files?.[0])} />
         <div className="flex flex-wrap items-center gap-3">
           {latest && (
-            <button className="btn-primary" disabled={busy !== null} onClick={() => pickLatest()}>
+            <button className="btn-primary" disabled={busy !== null} onClick={() => pickBuild(latest)}>
               {busy === 'file' ? 'Reading…' : `Latest build: ${latest.release.title}${latest.file.build ? ` (build ${latest.file.build})` : ''}`}
             </button>
           )}

docs/deploy.md

@@ -438,7 +438,10 @@ DorkNet__Downloads__Host=<bucket name>
 
 Unset, the site hides both features. The builds contain Rec Room's own game
 files: only turn this on when the site is behind an access proxy (e.g.
-Cloudflare Access) that admits just your community.
+Cloudflare Access) that admits just your community. The downloads routes
+answer only on the apex host, where the site lives, and return 404 on every
+other host the server accepts, so leaving the game's own subdomains open for
+the client doesn't expose the files. Put the apex behind the proxy.
 
 ---