OverwriteResponseEvent for optionally modifying events before sending them to client.

add-event.go

@@ -86,7 +86,11 @@ func (rl *Relay) AddEvent(ctx context.Context, evt *nostr.Event) error {
 		}
 	}
 
+	for _, ovw := range rl.OverwriteResponseEvent {
+		ovw(ctx, evt)
+	}
 	notifyListeners(evt)
+
 	return nil
 }
 

go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/fasthttp/websocket v1.5.3
 	github.com/fiatjaf/eventstore v0.1.0
 	github.com/gobwas/ws v1.2.0
-	github.com/nbd-wtf/go-nostr v0.25.0
+	github.com/nbd-wtf/go-nostr v0.25.1
 	github.com/puzpuzpuz/xsync/v2 v2.5.1
 	github.com/rs/cors v1.7.0
 	golang.org/x/exp v0.0.0-20230425010034-47ecfdc1ba53

go.sum

@@ -90,8 +90,8 @@ github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJ
 github.com/mattn/go-sqlite3 v1.14.6/go.mod h1:NyWgC/yNuGj7Q9rpYnZvas74GogHl5/Z4A/KQRfk6bU=
 github.com/mattn/go-sqlite3 v1.14.17 h1:mCRHCLDUBXgpKAqIKsaAaAsrAlbkeomtRFKXh2L6YIM=
 github.com/mattn/go-sqlite3 v1.14.17/go.mod h1:2eHXhiwb8IkHr+BDWZGa96P6+rkvnG63S2DGjv9HUNg=
-github.com/nbd-wtf/go-nostr v0.25.0 h1:6ArnEX5NqjTaIBH6F5KYIJ0uw0uaKSWu8zjDb9za0Cg=
-github.com/nbd-wtf/go-nostr v0.25.0/go.mod h1:bkffJI+x914sPQWum9ZRUn66D7NpDnAoWo1yICvj3/0=
+github.com/nbd-wtf/go-nostr v0.25.1 h1:YTLTDUgngfzd3qQ0fWmQmq20flwnGtHH0g0Q8S3HlW4=
+github.com/nbd-wtf/go-nostr v0.25.1/go.mod h1:bkffJI+x914sPQWum9ZRUn66D7NpDnAoWo1yICvj3/0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=

handlers.go

@@ -124,12 +124,10 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 
 					// check signature (requires the ID to be set)
 					if ok, err := evt.CheckSignature(); err != nil {
-						reason := "error: failed to verify signature"
-						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: &reason})
+						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "error: failed to verify signature"})
 						return
 					} else if !ok {
-						reason := "invalid: signature is invalid"
-						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: &reason})
+						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "invalid: signature is invalid"})
 						return
 					}
 
@@ -139,12 +137,12 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 					} else {
 						err = rl.AddEvent(ctx, &evt)
 					}
-					var reason *string
+
+					var reason string
 					if err == nil {
 						ok = true
 					} else {
-						msg := err.Error()
-						reason = &msg
+						reason = err.Error()
 					}
 					ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: ok, Reason: reason})
 				case "COUNT":
@@ -236,6 +234,9 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 
 							go func(ch chan *nostr.Event) {
 								for event := range ch {
+									for _, ovw := range rl.OverwriteResponseEvent {
+										ovw(ctx, event)
+									}
 									ws.WriteJSON(nostr.EventEnvelope{SubscriptionID: &id, Event: *event})
 								}
 								eose.Done()
@@ -273,8 +274,7 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 							ctx = context.WithValue(ctx, AUTH_CONTEXT_KEY, pubkey)
 							ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: true})
 						} else {
-							reason := "error: failed to authenticate"
-							ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: &reason})
+							ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "error: failed to authenticate"})
 						}
 					}
 				}

relay.go

@@ -45,6 +45,7 @@ type Relay struct {
 	RejectFilter             []func(ctx context.Context, filter nostr.Filter) (reject bool, msg string)
 	RejectCountFilter        []func(ctx context.Context, filter nostr.Filter) (reject bool, msg string)
 	OverwriteDeletionOutcome []func(ctx context.Context, target *nostr.Event, deletion *nostr.Event) (acceptDeletion bool, msg string)
+	OverwriteResponseEvent   []func(ctx context.Context, event *nostr.Event)
 	StoreEvent               []func(ctx context.Context, event *nostr.Event) error
 	DeleteEvent              []func(ctx context.Context, event *nostr.Event) error
 	QueryEvents              []func(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error)