staticfiles: Expand placeholder for index files (#4679)

caddytest/integration/caddyfile_test.go

@@ -101,3 +101,27 @@ func TestReadCookie(t *testing.T) {
 	// act and assert
 	tester.AssertGetResponse("http://localhost:9080/cookie.html", 200, "<h2>Cookie.ClientName caddytest</h2>")
 }
+
+func TestReplIndex(t *testing.T) {
+
+	tester := caddytest.NewTester(t)
+	tester.InitServer(`
+  {
+    http_port     9080
+    https_port    9443
+  }
+
+  localhost:9080 {
+    templates {
+      root testdata
+    }
+    file_server {
+      root testdata
+      index "index.{host}.html"
+    }
+  }
+  `, "caddyfile")
+
+	// act and assert
+	tester.AssertGetResponse("http://localhost:9080/", 200, "")
+}

modules/caddyhttp/fileserver/staticfiles.go

@@ -200,6 +200,7 @@ func (fsrv *FileServer) ServeHTTP(w http.ResponseWriter, r *http.Request, next c
 	var implicitIndexFile bool
 	if info.IsDir() && len(fsrv.IndexNames) > 0 {
 		for _, indexPage := range fsrv.IndexNames {
+			indexPage := repl.ReplaceAll(indexPage, "")
 			indexPath := caddyhttp.SanitizedPathJoin(filename, indexPage)
 			if fileHidden(indexPath, filesToHide) {
 				// pretend this file doesn't exist