fix(web): bound the panel's open connections and share asset gzip

The engine-wide gzip middleware gave every in-flight request its own compressor of about 1 MiB, and the public /assets bundles let an anonymous client keep a handler blocked in Write until WriteTimeout, so a thousand stalled downloads held a gigabyte. The listener itself took any number of connections, each holding buffers and a goroutine before any login. The bundles are now served from a gzip copy made once per file, with the assets prefix left out of the per-request middleware, and the panel listener closes a new connection once 2048 are open or its source (an IPv4 address or IPv6 /64) holds 256; a loopback reverse proxy counts only toward the total.
2026-11-02 11:15:03 +03:00 · 2026-11-01 01:01:38 +01:00
parent 1c748adadf
commit 3526a65f5d
7 changed files with 436 additions and 11 deletions
@@ -0,0 +1,89 @@
+package web
+
+import (
+	"bytes"
+	"compress/gzip"
+	"io"
+	"io/fs"
+	"net/http"
+	"net/http/httptest"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+// Any per-request compressor here is pinned for as long as an anonymous client
+// stalls its download, so the bundles must come out as one shared gzip copy.
+func TestAssetsServedFromSharedGzipCopy(t *testing.T) {
+	entries, err := fs.ReadDir(distFS, "dist/assets")
+	if err != nil || len(entries) == 0 {
+		t.Skip("no built frontend bundles embedded (dist stub)")
+	}
+	name := ""
+	for _, e := range entries {
+		if strings.HasSuffix(e.Name(), ".js") {
+			name = e.Name()
+			break
+		}
+	}
+	if name == "" {
+		t.Skip("no .js bundle embedded")
+	}
+	raw, err := fs.ReadFile(distFS, "dist/assets/"+name)
+	if err != nil {
+		t.Fatal(err)
+	}
+	engine := newTestEngine(t)
+
+	get := func(acceptEncoding string) *http.Response {
+		t.Helper()
+		req := httptest.NewRequest(http.MethodGet, "/assets/"+name, nil)
+		req.Header.Set("Accept-Encoding", acceptEncoding)
+		w := httptest.NewRecorder()
+		engine.ServeHTTP(w, req)
+		return w.Result()
+	}
+
+	for range 2 {
+		res := get("gzip")
+		body, _ := io.ReadAll(res.Body)
+		if res.StatusCode != http.StatusOK || res.Header.Get("Content-Encoding") != "gzip" {
+			t.Fatalf("gzip download: got %d, Content-Encoding %q", res.StatusCode, res.Header.Get("Content-Encoding"))
+		}
+		// A precompressed copy is sent with its length; a streamed compressor can't know it.
+		if got := res.Header.Get("Content-Length"); got != strconv.Itoa(len(body)) {
+			t.Errorf("Content-Length = %q, want %d: bundle was compressed per request", got, len(body))
+		}
+		if res.Header.Get("Last-Modified") == "" {
+			t.Error("Last-Modified missing: assets FS no longer stamps startTime")
+		}
+		zr, err := gzip.NewReader(bytes.NewReader(body))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if plain, _ := io.ReadAll(zr); !bytes.Equal(plain, raw) {
+			t.Fatal("gzip download decompresses to something other than the bundle")
+		}
+	}
+
+	res := get("")
+	body, _ := io.ReadAll(res.Body)
+	if res.StatusCode != http.StatusOK || res.Header.Get("Content-Encoding") != "" || !bytes.Equal(body, raw) {
+		t.Fatalf("plain download: got %d, Content-Encoding %q, %d bytes", res.StatusCode, res.Header.Get("Content-Encoding"), len(body))
+	}
+}
+
+// The assets route never listed its directory; serving the bundles from a shared copy
+// must not turn that 404 into a 500.
+func TestAssetsDirectoryIsNotFound(t *testing.T) {
+	engine := newTestEngine(t)
+	for _, encoding := range []string{"", "gzip"} {
+		req := httptest.NewRequest(http.MethodGet, "/assets/", nil)
+		req.Header.Set("Accept-Encoding", encoding)
+		w := httptest.NewRecorder()
+		engine.ServeHTTP(w, req)
+		if w.Code != http.StatusNotFound {
+			t.Errorf("GET /assets/ with Accept-Encoding %q = %d, want 404", encoding, w.Code)
+		}
+	}
+}