fix sign on error checking.

examples/exclusive/main.go

@@ -26,7 +26,7 @@ func main() {
 	relay.CountEvents = append(relay.CountEvents, db.CountEvents)
 	relay.DeleteEvent = append(relay.DeleteEvent, db.DeleteEvent)
 
-	relay.RejectEvent = append(relay.RejectEvent, policies.PreventTooManyIndexableTags(10))
+	relay.RejectEvent = append(relay.RejectEvent, policies.PreventTooManyIndexableTags(10, nil, nil))
 	relay.RejectFilter = append(relay.RejectFilter, policies.NoComplexFilters)
 
 	relay.OnEventSaved = append(relay.OnEventSaved, func(ctx context.Context, event *nostr.Event) {

examples/readme-demo/main.go

@@ -60,15 +60,20 @@ func main() {
 			return false, "" // anyone else can
 		},
 	)
-	relay.OnConnect = append(relay.OnConnect,
-		func(ctx context.Context) {
-			// request NIP-42 AUTH from everybody
-			relay.RequestAuth(ctx)
+
+	// you can request auth by rejecting an event or a request with the prefix "auth-required: "
+	relay.RejectFilter = append(relay.RejectFilter,
+		func(ctx context.Context, filter nostr.Filter) (reject bool, msg string) {
+			if pubkey := khatru.GetAuthed(ctx); pubkey != "" {
+				log.Printf("request from %s\n", pubkey)
+				return false, ""
+			}
+			return true, "auth-required: only authenticated users can read from this relay"
 		},
 	)
 	relay.OnAuth = append(relay.OnAuth,
 		func(ctx context.Context, pubkey string) {
-			// and when they auth we just log that for nothing
+			// and when they auth we can just log that for nothing
 			log.Println(pubkey + " is authed!")
 		},
 	)

handlers.go

@@ -19,6 +19,10 @@ import (
 
 // ServeHTTP implements http.Handler interface.
 func (rl *Relay) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if rl.ServiceURL == "" {
+		rl.ServiceURL = getServiceBaseURL(r)
+	}
+
 	if r.Header.Get("Upgrade") == "websocket" {
 		rl.HandleWebsocket(w, r)
 	} else if r.Header.Get("Accept") == "application/nostr+json" {
@@ -29,7 +33,7 @@ func (rl *Relay) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 }
 
 func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
-	ctx := r.Context()
+	connectionContext := r.Context()
 
 	conn, err := rl.upgrader.Upgrade(w, r, nil)
 	if err != nil {
@@ -50,7 +54,7 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 		Authed:    make(chan struct{}),
 	}
 
-	ctx = context.WithValue(ctx, WS_KEY, ws)
+	connectionContext = context.WithValue(connectionContext, WS_KEY, ws)
 
 	// reader
 	go func() {
@@ -71,7 +75,7 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 		})
 
 		for _, onconnect := range rl.OnConnect {
-			onconnect(ctx)
+			onconnect(connectionContext)
 		}
 
 		for {
@@ -95,7 +99,13 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 			}
 
 			go func(message []byte) {
-				ctx := context.WithValue(context.Background(), WS_KEY, ws)
+				ctx := context.WithValue(
+					context.WithValue(
+						context.Background(),
+						AUTH_CONTEXT_KEY, connectionContext.Value(AUTH_CONTEXT_KEY),
+					),
+					WS_KEY, ws,
+				)
 
 				envelope := nostr.ParseMessage(message)
 				if envelope == nil {
@@ -134,6 +144,9 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 						ok = true
 					} else {
 						reason = nostr.NormalizeOKMessage(err.Error(), "blocked")
+						if isAuthRequired(reason) {
+							ws.WriteJSON(nostr.AuthEnvelope{Challenge: &ws.Challenge})
+						}
 					}
 					ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: ok, Reason: reason})
 				case *nostr.CountEnvelope:
@@ -152,8 +165,11 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 
 					for _, filter := range env.Filters {
 						err := rl.handleRequest(ctx, env.SubscriptionID, &eose, ws, filter)
-						if err == nil {
+						if err != nil {
 							reason := nostr.NormalizeOKMessage(err.Error(), "blocked")
+							if isAuthRequired(reason) {
+								ws.WriteJSON(nostr.AuthEnvelope{Challenge: &ws.Challenge})
+							}
 							ws.WriteJSON(nostr.ClosedEnvelope{SubscriptionID: env.SubscriptionID, Reason: reason})
 							return
 						}
@@ -168,15 +184,14 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 				case *nostr.CloseEnvelope:
 					removeListenerId(ws, string(*env))
 				case *nostr.AuthEnvelope:
-					if rl.ServiceURL != "" {
-						if pubkey, ok := nip42.ValidateAuthEvent(&env.Event, ws.Challenge, rl.ServiceURL); ok {
-							ws.AuthedPublicKey = pubkey
-							close(ws.Authed)
-							ctx = context.WithValue(ctx, AUTH_CONTEXT_KEY, pubkey)
-							ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: true})
-						} else {
-							ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: false, Reason: "error: failed to authenticate"})
-						}
+					wsBaseUrl := strings.Replace(rl.ServiceURL, "http", "ws", 1)
+					if pubkey, ok := nip42.ValidateAuthEvent(&env.Event, ws.Challenge, wsBaseUrl); ok {
+						ws.AuthedPublicKey = pubkey
+						close(ws.Authed)
+						connectionContext = context.WithValue(ctx, AUTH_CONTEXT_KEY, pubkey)
+						ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: true})
+					} else {
+						ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: false, Reason: "error: failed to authenticate"})
 					}
 				}
 			}(message)

helpers.go

@@ -0,0 +1,55 @@
+package khatru
+
+import (
+	"hash/maphash"
+	"net/http"
+	"regexp"
+	"strconv"
+	"strings"
+	"unsafe"
+
+	"github.com/nbd-wtf/go-nostr"
+)
+
+const (
+	AUTH_CONTEXT_KEY = iota
+	WS_KEY
+)
+
+var nip20prefixmatcher = regexp.MustCompile(`^\w+: `)
+
+func pointerHasher[V any](_ maphash.Seed, k *V) uint64 {
+	return uint64(uintptr(unsafe.Pointer(k)))
+}
+
+func isOlder(previous, next *nostr.Event) bool {
+	return previous.CreatedAt < next.CreatedAt ||
+		(previous.CreatedAt == next.CreatedAt && previous.ID > next.ID)
+}
+
+func isAuthRequired(msg string) bool {
+	idx := strings.IndexByte(msg, ':')
+	return msg[0:idx] == "auth-required"
+}
+
+func getServiceBaseURL(r *http.Request) string {
+	host := r.Header.Get("X-Forwarded-Host")
+	if host == "" {
+		host = r.Host
+	}
+	proto := r.Header.Get("X-Forwarded-Proto")
+	if proto == "" {
+		if host == "localhost" {
+			proto = "http"
+		} else if strings.Index(host, ":") != -1 {
+			// has a port number
+			proto = "http"
+		} else if _, err := strconv.Atoi(strings.ReplaceAll(host, ".", "")); err == nil {
+			// it's a naked IP
+			proto = "http"
+		} else {
+			proto = "https"
+		}
+	}
+	return proto + "://" + host
+}

relay.go

@@ -40,7 +40,7 @@ func NewRelay() *Relay {
 }
 
 type Relay struct {
-	ServiceURL string // required for nip-42
+	ServiceURL string
 
 	RejectEvent               []func(ctx context.Context, event *nostr.Event) (reject bool, msg string)
 	RejectFilter              []func(ctx context.Context, filter nostr.Filter) (reject bool, msg string)
@@ -82,8 +82,3 @@ type Relay struct {
 	PingPeriod     time.Duration // Send pings to peer with this period. Must be less than pongWait.
 	MaxMessageSize int64         // Maximum message size allowed from peer.
 }
-
-func (rl *Relay) RequestAuth(ctx context.Context) {
-	ws := GetConnection(ctx)
-	ws.WriteJSON(nostr.AuthEnvelope{Challenge: &ws.Challenge})
-}

utils.go

@@ -2,20 +2,8 @@ package khatru
 
 import (
 	"context"
-	"hash/maphash"
-	"regexp"
-	"unsafe"
-
-	"github.com/nbd-wtf/go-nostr"
 )
 
-const (
-	AUTH_CONTEXT_KEY = iota
-	WS_KEY           = iota
-)
-
-var nip20prefixmatcher = regexp.MustCompile(`^\w+: `)
-
 func GetConnection(ctx context.Context) *WebSocket {
 	return ctx.Value(WS_KEY).(*WebSocket)
 }
@@ -27,12 +15,3 @@ func GetAuthed(ctx context.Context) string {
 	}
 	return authedPubkey.(string)
 }
-
-func pointerHasher[V any](_ maphash.Seed, k *V) uint64 {
-	return uint64(uintptr(unsafe.Pointer(k)))
-}
-
-func isOlder(previous, next *nostr.Event) bool {
-	return previous.CreatedAt < next.CreatedAt ||
-		(previous.CreatedAt == next.CreatedAt && previous.ID > next.ID)
-}