khatru: optional ChallengePrefix.

khatru/handlers.go

@@ -75,7 +75,7 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 	ws := &WebSocket{
 		conn:               conn,
 		Request:            r,
-		Challenge:          hex.EncodeToString(challenge),
+		Challenge:          rl.ChallengePrefix + hex.EncodeToString(challenge),
 		negentropySessions: xsync.NewMapOf[string, *NegentropySession](),
 	}
 	ws.Context, ws.cancel = context.WithCancel(context.Background())

khatru/relay.go

@@ -75,6 +75,9 @@ type Relay struct {
 	OverwriteRelayInformation func(ctx context.Context, r *http.Request, info nip11.RelayInformationDocument) nip11.RelayInformationDocument
 	PreventBroadcast          func(ws *WebSocket, event nostr.Event) bool
 
+	// this can be ignored unless you know what you're doing
+	ChallengePrefix string
+
 	// these are used when this relays acts as a router
 	routes                []Route
 	getSubRelayFromEvent  func(*nostr.Event) *Relay // used for handling EVENTs