From c68eaf53c2dd1f91e7f6987693a021afb9881255 Mon Sep 17 00:00:00 2001
From: Local Dev <dev@localhost>
Date: Wed, 16 Sep 2026 19:24:29 +0200
Subject: [PATCH] fix(argus): try dir-index before SPA fallback for
 extensionless paths
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Two-tier fallback for extensionless paths that miss in Sia. The
previous change went straight to root index.html, which meant a real
sub-site living at "<name>/about/index.html" got shadowed by the SPA
root — visitors requesting "/about" got served the app instead of
the landing page.

New chain (matches nginx try_files order):
  1) request path              → /about
     hit: bns/potidaea/about   → 404
  2) directory index attempt   → /about/
     hit: bns/potidaea/about/index.html → 200 · SERVE
  3) if still 404, SPA root    → bns/potidaea/index.html → 200

Trailing-slash requests still short-circuit to their own index.html
via the existing `rel` derivation (unchanged), so /about/ has been
working the whole time; only the bare /about was falling through
to the SPA rescue.

Deployed to silentmode 2026-09-16:
  scp Argus/src/gateway/public-gateway.mjs
      silentmode:/tmp/public-gateway.mjs
  sudo cp … /opt/bns-gateway/public-gateway.mjs
  sudo systemctl restart bns-gateway
---
 src/gateway/public-gateway.mjs | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/gateway/public-gateway.mjs b/src/gateway/public-gateway.mjs
index a5627e6..4bf0dca 100644
--- a/src/gateway/public-gateway.mjs
+++ b/src/gateway/public-gateway.mjs
@@ -235,15 +235,28 @@ async function serve(res, name, reqPath, baseHref) {
                   : reqPath.slice(1);
         const key = base.endsWith("/") ? base + rel : base;
         let up = await aws.fetch(`${S3_ENDPOINT}/${key}`);
-        // SPA fallback — if the extension-less path 404s, serve the domain's
-        // own index.html so client-side routers (History API) can pick up
-        // /katalogos, /anthemus, /artemision, etc. under any BNS mount.
-        // We only fall back when the requested path has no file extension —
-        // requests for missing images / json / js still 404 as they should.
+        // Fallback chain for missing extensionless paths (order matters):
+        //   1) directory-index: try "<path>/index.html" — matches nginx
+        //      try_files. This handles static sub-sites like /about that
+        //      have their own index.html.
+        //   2) SPA fallback: serve the domain's ROOT index.html so
+        //      client-side routers can pick up /katalogos, /anthemus, etc.
+        // Requests with a file extension (missing .png / .js / .json) are
+        // NOT rescued — those should never be routed by a client-side
+        // router and swallowing them would hide real bugs.
         if (up.status === 404 && !/\.[a-z0-9]+$/i.test(reqPath) && reqPath !== "/") {
-          const fallbackKey = (base.endsWith("/") ? base : base + "/") + "index.html";
-          const fb = await aws.fetch(`${S3_ENDPOINT}/${fallbackKey}`);
-          if (fb.ok) { up = fb; }
+          // Try directory-index first
+          if (!reqPath.endsWith("/")) {
+            const dirKey = (base.endsWith("/") ? base : base + "/") + reqPath.slice(1).replace(/\/+$/, '') + "/index.html";
+            const dir = await aws.fetch(`${S3_ENDPOINT}/${dirKey}`);
+            if (dir.ok) { up = dir; }
+          }
+          // Then SPA root fallback
+          if (up.status === 404) {
+            const fallbackKey = (base.endsWith("/") ? base : base + "/") + "index.html";
+            const fb = await aws.fetch(`${S3_ENDPOINT}/${fallbackKey}`);
+            if (fb.ok) { up = fb; }
+          }
         }
         const buf = Buffer.from(await up.arrayBuffer());
         let ct = up.headers.get("content-type"); if (!ct || ct === "application/octet-stream") ct = guess(key);