From a1f69662006ea6c22b710274b1ba92a1711053a7 Mon Sep 17 00:00:00 2001
From: Grendgi <barsagaev39@gmail.com>
Date: Mon, 15 Jun 2026 11:20:34 +0300
Subject: [PATCH] Add portal header helpers

---
 middleware/headers.go | 45 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 middleware/headers.go

diff --git a/middleware/headers.go b/middleware/headers.go
new file mode 100644
index 0000000..177bfc8
--- /dev/null
+++ b/middleware/headers.go
@@ -0,0 +1,45 @@
+package middleware
+
+import (
+	"net/http"
+	"strings"
+)
+
+// HeaderBool reads portal-proxy boolean headers.
+// Contract: "1", "true", "yes" and "on" are true; everything else is false.
+func HeaderBool(r *http.Request, name string) bool {
+	switch strings.ToLower(strings.TrimSpace(r.Header.Get(name))) {
+	case "1", "true", "yes", "on":
+		return true
+	default:
+		return false
+	}
+}
+
+// HeaderCSV returns a trimmed non-empty CSV list from a portal-proxy header.
+func HeaderCSV(r *http.Request, name string) []string {
+	raw := strings.TrimSpace(r.Header.Get(name))
+	if raw == "" {
+		return nil
+	}
+	parts := strings.Split(raw, ",")
+	out := make([]string, 0, len(parts))
+	for _, part := range parts {
+		if v := strings.TrimSpace(part); v != "" {
+			out = append(out, v)
+		}
+	}
+	return out
+}
+
+// HeaderScope returns a lower-cased scope constrained to allowed values.
+// The fallback is returned when the header is empty or unknown.
+func HeaderScope(r *http.Request, name, fallback string, allowed ...string) string {
+	value := strings.ToLower(strings.TrimSpace(r.Header.Get(name)))
+	for _, option := range allowed {
+		if value == strings.ToLower(strings.TrimSpace(option)) {
+			return value
+		}
+	}
+	return fallback
+}