Get service url when handling auth rather than mutating the relay, allow user to override service url via env var

handlers.go

@@ -6,6 +6,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"net/http"
+	"os"
 	"strings"
 	"sync"
 	"time"
@@ -24,10 +25,6 @@ import (
 
 // ServeHTTP implements http.Handler interface.
 func (rl *Relay) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	if rl.ServiceURL == "" {
-		rl.ServiceURL = getServiceBaseURL(r)
-	}
-
 	corsMiddleware := cors.New(cors.Options{
 		AllowedOrigins: []string{"*"},
 		AllowedMethods: []string{
@@ -319,7 +316,10 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 					id := string(*env)
 					rl.removeListenerId(ws, id)
 				case *nostr.AuthEnvelope:
-					wsBaseUrl := strings.Replace(rl.ServiceURL, "http", "ws", 1)
+					wsBaseUrl := os.Getenv("RELAY_URL")
+					if wsBaseUrl == "" {
+						wsBaseUrl = strings.Replace(getServiceBaseURL(r), "http", "ws", 1)
+					}
 					if pubkey, ok := nip42.ValidateAuthEvent(&env.Event, ws.Challenge, wsBaseUrl); ok {
 						ws.AuthedPublicKey = pubkey
 						ws.authLock.Lock()

nip86.go

@@ -80,7 +80,7 @@ func (rl *Relay) HandleNIP86(w http.ResponseWriter, r *http.Request) {
 			goto respond
 		}
 
-		if uTag := evt.Tags.GetFirst([]string{"u", ""}); uTag == nil || rl.ServiceURL != (*uTag)[1] {
+		if uTag := evt.Tags.GetFirst([]string{"u", ""}); uTag == nil || getServiceBaseURL(r) != (*uTag)[1] {
 			resp.Error = "invalid 'u' tag"
 			goto respond
 		} else if pht := evt.Tags.GetFirst([]string{"payload", hex.EncodeToString(payloadHash[:])}); pht == nil {

relay.go

@@ -45,8 +45,6 @@ func NewRelay() *Relay {
 }
 
 type Relay struct {
-	ServiceURL string
-
 	// hooks that will be called at various times
 	RejectEvent               []func(ctx context.Context, event *nostr.Event) (reject bool, msg string)
 	OverwriteDeletionOutcome  []func(ctx context.Context, target *nostr.Event, deletion *nostr.Event) (acceptDeletion bool, msg string)