Fix empty response bodies through the web proxy

.github/workflows/ci.yml

@@ -122,16 +122,27 @@ jobs:
             *) echo "expected the inbox or a redirect to /login"; docker logs og; exit 1 ;;
           esac
 
-      - name: The landing page is public
+      - name: The landing page is public and actually has a body
         run: |
-          # / must render for a signed-out visitor, not redirect to /login.
-          code=$(curl -s -o /dev/null -w '%{http_code}' http://127.0.0.1:8080/)
-          echo "GET / -> $code"
+          # --compressed matters: plain curl sends no Accept-Encoding, but every
+          # browser does. A proxy that forwards the child's content-encoding
+          # while fetch has already decompressed the body returns a 200 with
+          # zero bytes — which shipped once, and which a bare curl cannot see.
+          code=$(curl -s --compressed -o /tmp/landing.html -w '%{http_code}' http://127.0.0.1:8080/)
+          bytes=$(wc -c < /tmp/landing.html)
+          echo "GET / -> $code, $bytes bytes"
+
           [ "$code" = "200" ] || { echo "the landing page must be public"; docker logs og; exit 1; }
+          [ "$bytes" -gt 1000 ] || { echo "landing page body is empty or truncated"; docker logs og; exit 1; }
 
-          curl -s http://127.0.0.1:8080/ | grep -q "warm conversations" \
+          grep -q "warm conversations" /tmp/landing.html \
             || { echo "landing page did not render its content"; exit 1; }
 
+          # The signed-in shell must survive compression too.
+          login_bytes=$(curl -s --compressed http://127.0.0.1:8080/login | wc -c)
+          echo "GET /login -> $login_bytes bytes"
+          [ "$login_bytes" -gt 500 ] || { echo "/login body is empty"; docker logs og; exit 1; }
+
       - name: Auth is enforced
         run: |
           code=$(curl -s -o /dev/null -w '%{http_code}' http://127.0.0.1:8080/api/v1/recommendations)

apps/server/src/index.ts

@@ -113,10 +113,19 @@ async function proxyToWeb(request: Request): Promise<Response> {
   const incoming = new URL(request.url);
   const target = new URL(incoming.pathname + incoming.search, `http://127.0.0.1:${WEB_PORT}`);
 
+  // Ask the child for identity encoding. `fetch` transparently decompresses
+  // what it receives, so a forwarded `content-encoding: gzip` would describe a
+  // body that is no longer compressed — the client then fails to decode it and
+  // renders nothing. Not requesting compression over loopback avoids the
+  // mismatch entirely and costs nothing.
+  const headers = new Headers(request.headers);
+  headers.set('accept-encoding', 'identity');
+
+  let response: Response;
   try {
-    return await fetch(target, {
+    response = await fetch(target, {
       method: request.method,
-      headers: request.headers,
+      headers,
       body: request.method === 'GET' || request.method === 'HEAD' ? undefined : request.body,
       redirect: 'manual',
       // Streaming bodies require this; without it Bun buffers and rejects.
@@ -126,6 +135,21 @@ async function proxyToWeb(request: Request): Promise<Response> {
     console.error('web proxy failed', error);
     return new Response('the web application is not responding', { status: 502 });
   }
+
+  // Strip hop-by-hop and body-framing headers. Whatever the child said about
+  // length or encoding describes its own wire format, not the one this
+  // response will be sent with.
+  const outbound = new Headers(response.headers);
+  outbound.delete('content-encoding');
+  outbound.delete('content-length');
+  outbound.delete('transfer-encoding');
+  outbound.delete('connection');
+
+  return new Response(response.body, {
+    status: response.status,
+    statusText: response.statusText,
+    headers: outbound,
+  });
 }
 
 // ------------------------------------------------------------------- server