Skip /js/ in the Access Gate and set denied-page CSP so Denied UI can render.

Co-authored-by: Cursor <cursoragent@cursor.com>

CONTEXT.md

@@ -25,5 +25,9 @@ The Nextcloud groups configured for an ExApp (comma-separated deploy env `REQUIR
 _Avoid_: AppAPI scopes, route access_level, admin-only top menu, treating the ExApp id as an implicit group name
 
 **Access Gate**:
-The Library check that enforces Required Groups for the Requesting user on ExApp HTTP traffic (403 or denied UI when not a member; 401 without a user; 503 when membership cannot be determined). Lifecycle paths stay ungated.
+The Library check that enforces Required Groups for the Requesting user on ExApp HTTP traffic (403 or denied UI when not a member; 401 without a user; 503 when membership cannot be determined). Lifecycle paths and top-menu script URLs under `/js/` stay ungated so Denied UI can load in the Nextcloud shell.
-_Avoid_: Nextcloud middleware, HaRP ACL, admin bypass
+_Avoid_: Nextcloud middleware, HaRP ACL, admin bypass, gating the top-menu bootstrap script
+
+**Top Menu visibility**:
+Whether the ExApp app icon in the Nextcloud top menu is shown to all logged-in users or to Nextcloud admins only. Configured per deploy via env `TOP_MENU_ADMIN_REQUIRED` (`0` or `1`); the ExApp passes the value to AppAPI when registering the top-menu entry on enable. Independent of route `access_level` in info.xml and of Required Groups.
+_Avoid_: route access_level, Required Groups, AppAPI group ACL

README.md

@@ -14,7 +14,8 @@ Import: `gitea.neitzel.de/konrad/go-nc-exapp` (package `gonexapp`).
 - **UserFromRequest** — extract the requesting user from inbound AppAPI-proxied requests
 - **OCSClient** — authenticated OCS calls that always append `format=json`
 - **AppAPIPreferences** — parameterized get/set of a string ExApp preference (caller supplies app id and key)
-- **Access Gate** — optional Required Groups enforcement (`Wrap` + `Check`), English denied HTML for browsers, positive membership cache; env helpers for `REQUIRED_GROUPS` / `REQUIRED_GROUPS_CACHE_SECONDS`
+- **Access Gate** — optional Required Groups enforcement (`Wrap` + `Check`), English denied HTML for browsers (200 + `frame-ancestors 'self'`), positive membership cache; default skip for lifecycle paths and **`/js/`** top-menu scripts; env helpers for `REQUIRED_GROUPS` / `REQUIRED_GROUPS_CACHE_SECONDS`
+- **Top Menu visibility** — `TopMenuAdminRequired` helper for deploy env `TOP_MENU_ADMIN_REQUIRED` (`0` / `1` for AppAPI top-menu OCS)
 
 **Excluded**
 
@@ -49,11 +50,35 @@ Each ExApp chooses its own preference keys; this library does not hardcode produ
 
 Declare `REQUIRED_GROUPS` and `REQUIRED_GROUPS_CACHE_SECONDS` in the ExApp `info.xml` so Deploy options can set them.
 
+The Gate skips `/heartbeat`, `/enabled`, `/init`, and any path under **`/js/`** (AppAPI top-menu bootstrap). Serve the registered top-menu script under `/js/…` so a non-member still loads it and can show Denied UI in the Nextcloud shell. API routes stay gated.
+
+Denied HTML is **200** with `Content-Security-Policy: … frame-ancestors 'self'`. Without that header AppAPI’s proxy defaults to `frame-ancestors 'none'` and a denied iframe stays blank. Non-HTML denials remain **403**.
+
+### Top Menu visibility (`TOP_MENU_ADMIN_REQUIRED`)
+
+Declare in `info.xml` under `<environment-variables>`. At enable time the ExApp reads the env and passes `"0"` or `"1"` to AppAPI’s top-menu OCS `adminRequired`. Only `0` and `1` are valid; anything else falls back to `DefaultTopMenuAdminRequired` (`true` → admins only).
+
+```go
+adminRequired := gonexapp.TopMenuAdminRequired(
+    os.Getenv(gonexapp.EnvTopMenuAdminRequired),
+    gonexapp.DefaultTopMenuAdminRequired,
+)
+// use adminRequired in POST …/ui/top-menu when registering the menu entry
+```
+
+**Applying a change:** AppAPI registers the top menu when the ExApp receives `PUT /enabled?enabled=1`. Changing the deploy env alone does not update the menu entry.
+
+1. Set the new value in Deploy options (UI) or `occ app_api:app:register … --env TOP_MENU_ADMIN_REQUIRED=…` / update deploy config.
+2. Recreate or restart the ExApp container so the new env is present.
+3. Re-run lifecycle: disable then enable the ExApp (UI or `occ app_api:app:disable` / `app_api:app:enable`), or `occ app_api:app:update … -e` after an image/info update.
+
+Route `access_level` in `info.xml` is separate and only changes when AppAPI re-reads `info.xml` on register/update — not via this env.
+
 Runnable package examples: `go test -run Example`.
 
 ## Domain language
 
-See [CONTEXT.md](./CONTEXT.md) for AppAPI credentials, Requesting user, ExApp preference, OCS, Required Groups, and Access Gate terminology.
+See [CONTEXT.md](./CONTEXT.md) for AppAPI credentials, Requesting user, ExApp preference, OCS, Required Groups, Access Gate, and Top Menu visibility terminology.
 
 ## Testing
 

access_gate.go

@@ -181,9 +181,10 @@ func (g AccessGate) normalized() *AccessGate {
 
 func (g *AccessGate) writeDenied(w http.ResponseWriter, r *http.Request) {
 	if acceptsHTML(r.Header.Get("Accept")) {
-		// 200 so AppAPI's proxy CSP keeps frame-ancestors 'self' and the ExApp
+		// 200 plus frame-ancestors 'self': AppAPI's default proxy CSP uses
-		// iframe can show the message (403 responses get frame-ancestors 'none').
+		// frame-ancestors 'none' unless the ExApp sets CSP, which blanks iframes.
 		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		w.Header().Set("Content-Security-Policy", deniedCSP)
 		w.WriteHeader(http.StatusOK)
 		_, _ = w.Write(deniedHTML)
 		return
@@ -197,6 +198,9 @@ func acceptsHTML(accept string) bool {
 
 func (g *AccessGate) shouldSkip(path string) bool {
 	path = normalizeGatePath(path)
+	if isTopMenuScriptPath(path) {
+		return true
+	}
 	for _, p := range defaultSkipPaths {
 		if path == p {
 			return true
@@ -210,6 +214,13 @@ func (g *AccessGate) shouldSkip(path string) bool {
 	return false
 }
 
+// isTopMenuScriptPath reports AppAPI top-menu bootstrap scripts under /js/.
+// Those must load for a non-member so the shell can show Denied UI; gating
+// them yields a blank embedded page (script Accept is not text/html → 403).
+func isTopMenuScriptPath(path string) bool {
+	return path == "/js" || strings.HasPrefix(path, "/js/")
+}
+
 func normalizeGatePath(path string) string {
 	path = strings.TrimSuffix(path, "/")
 	if path == "" {
@@ -220,6 +231,9 @@ func normalizeGatePath(path string) string {
 
 var defaultSkipPaths = []string{"/heartbeat", "/enabled", "/init"}
 
+// deniedCSP lets AppAPI proxy the denied page into an ExApp iframe.
+const deniedCSP = "default-src 'none'; base-uri 'none'; form-action 'none'; frame-ancestors 'self'; style-src 'unsafe-inline'"
+
 var deniedHTML = []byte(`<!DOCTYPE html>
 <html lang="en">
 <head>

access_gate_test.go

@@ -168,6 +168,31 @@ func TestAccessGateDeniesNonMemberWithHTML(t *testing.T) {
 	if !strings.Contains(rec.Body.String(), "Access denied") {
 		t.Fatalf("body=%q", rec.Body.String())
 	}
+	csp := rec.Header().Get("Content-Security-Policy")
+	if !strings.Contains(csp, "frame-ancestors 'self'") {
+		t.Fatalf("csp=%q", csp)
+	}
+}
+
+func TestAccessGateSkipsTopMenuScriptPrefix(t *testing.T) {
+	gate := gonexapp.AccessGate{Groups: []string{"dns-ops"}}
+	h := gate.Wrap(okInner())
+
+	for _, path := range []string{"/js/checkdns-main.js", "/js/app.js", "/js"} {
+		req := httptest.NewRequest(http.MethodGet, path, nil)
+		rec := httptest.NewRecorder()
+		h.ServeHTTP(rec, req)
+		if rec.Code != http.StatusOK || rec.Body.String() != "ok" {
+			t.Fatalf("%s: got %d %q", path, rec.Code, rec.Body.String())
+		}
+	}
+
+	req := httptest.NewRequest(http.MethodGet, "/json", nil)
+	rec := httptest.NewRecorder()
+	h.ServeHTTP(rec, req)
+	if rec.Code != http.StatusUnauthorized {
+		t.Fatalf("/json should stay gated, got %d", rec.Code)
+	}
 }
 
 func TestAccessGateLookupFailureServiceUnavailable(t *testing.T) {

example_test.go

@@ -71,7 +71,6 @@ func ExampleAccessGate_Wrap() {
 	inner := http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		_, _ = io.WriteString(w, "ok")
 	})
-	// Empty Required Groups: gate is inactive.
 	h := gonexapp.AccessGate{}.Wrap(inner)
 
 	rec := httptest.NewRecorder()
@@ -87,3 +86,11 @@ func ExampleResolveRequiredGroups() {
 	// []
 	// 0
 }
+
+func ExampleTopMenuAdminRequired() {
+	fmt.Println(gonexapp.TopMenuAdminRequired("0", gonexapp.DefaultTopMenuAdminRequired))
+	fmt.Println(gonexapp.TopMenuAdminRequired("maybe", gonexapp.DefaultTopMenuAdminRequired))
+	// Output:
+	// 0
+	// 1
+}

top_menu_env.go

@@ -0,0 +1,27 @@
+package gonexapp
+
+import "strings"
+
+// EnvTopMenuAdminRequired is the conventional deploy env name for Top Menu visibility.
+// Declare it in the ExApp info.xml environment-variables section.
+const EnvTopMenuAdminRequired = "TOP_MENU_ADMIN_REQUIRED"
+
+// DefaultTopMenuAdminRequired is used when TOP_MENU_ADMIN_REQUIRED is unset or invalid.
+const DefaultTopMenuAdminRequired = true
+
+// TopMenuAdminRequired returns "1" or "0" for the AppAPI top-menu OCS adminRequired field.
+// Only "0" and "1" are accepted; any other value falls back to defaultAdminRequired.
+// An empty envValue means unset and also uses defaultAdminRequired.
+func TopMenuAdminRequired(envValue string, defaultAdminRequired bool) string {
+	switch strings.TrimSpace(envValue) {
+	case "1":
+		return "1"
+	case "0":
+		return "0"
+	default:
+		if defaultAdminRequired {
+			return "1"
+		}
+		return "0"
+	}
+}

top_menu_env_test.go

@@ -0,0 +1,25 @@
+package gonexapp
+
+import "testing"
+
+func TestTopMenuAdminRequired(t *testing.T) {
+	tests := []struct {
+		env      string
+		defAdmin bool
+		want     string
+	}{
+		{"", true, "1"},
+		{"", false, "0"},
+		{"1", true, "1"},
+		{"0", true, "0"},
+		{" 1 ", true, "1"},
+		{"yes", true, "1"},
+		{"yes", false, "0"},
+		{"2", true, "1"},
+	}
+	for _, tc := range tests {
+		if got := TopMenuAdminRequired(tc.env, tc.defAdmin); got != tc.want {
+			t.Errorf("TopMenuAdminRequired(%q, %v) = %q, want %q", tc.env, tc.defAdmin, got, tc.want)
+		}
+	}
+}