Use responseModifier to override secure headers

vendor/github.com/unrolled/secure/csp.go

@@ -0,0 +1,44 @@
+package secure
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"io"
+	"net/http"
+)
+
+type key int
+
+const cspNonceKey key = iota
+
+// CSPNonce returns the nonce value associated with the present request. If no nonce has been generated it returns an empty string.
+func CSPNonce(c context.Context) string {
+	if val, ok := c.Value(cspNonceKey).(string); ok {
+		return val
+	}
+
+	return ""
+}
+
+// WithCSPNonce returns a context derived from ctx containing the given nonce as a value.
+//
+// This is intended for testing or more advanced use-cases;
+// For ordinary HTTP handlers, clients can rely on this package's middleware to populate the CSP nonce in the context.
+func WithCSPNonce(ctx context.Context, nonce string) context.Context {
+	return context.WithValue(ctx, cspNonceKey, nonce)
+}
+
+func withCSPNonce(r *http.Request, nonce string) *http.Request {
+	return r.WithContext(WithCSPNonce(r.Context(), nonce))
+}
+
+func cspRandNonce() string {
+	var buf [cspNonceSize]byte
+	_, err := io.ReadFull(rand.Reader, buf[:])
+	if err != nil {
+		panic("CSP Nonce rand.Reader failed" + err.Error())
+	}
+
+	return base64.RawStdEncoding.EncodeToString(buf[:])
+}