streamlined connection closes on failure.

account for the fact that the time.Ticker channel is
not closed when the ticker is stopped.

README.md

@@ -34,7 +34,7 @@ func main() {
 	relay.Info.Name = "my relay"
 	relay.Info.PubKey = "79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798"
 	relay.Info.Description = "this is my custom relay"
-	relay.Info.IconURL = "https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fliquipedia.net%2Fcommons%2Fimages%2F3%2F35%2FSCProbe.jpg&f=1&nofb=1&ipt=0cbbfef25bce41da63d910e86c3c343e6c3b9d63194ca9755351bb7c2efa3359&ipo=images"
+	relay.Info.Icon = "https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fliquipedia.net%2Fcommons%2Fimages%2F3%2F35%2FSCProbe.jpg&f=1&nofb=1&ipt=0cbbfef25bce41da63d910e86c3c343e6c3b9d63194ca9755351bb7c2efa3359&ipo=images"
 
 	// you must bring your own storage scheme -- if you want to have any
 	store := make(map[string]*nostr.Event, 120)

examples/exclusive/main.go

@@ -8,7 +8,7 @@ import (
 
 	"github.com/fiatjaf/eventstore/lmdb"
 	"github.com/fiatjaf/khatru"
-	"github.com/fiatjaf/khatru/plugins"
+	"github.com/fiatjaf/khatru/policies"
 	"github.com/nbd-wtf/go-nostr"
 )
 
@@ -26,8 +26,8 @@ func main() {
 	relay.CountEvents = append(relay.CountEvents, db.CountEvents)
 	relay.DeleteEvent = append(relay.DeleteEvent, db.DeleteEvent)
 
-	relay.RejectEvent = append(relay.RejectEvent, plugins.PreventTooManyIndexableTags(10))
+	relay.RejectEvent = append(relay.RejectEvent, policies.PreventTooManyIndexableTags(10, nil, nil))
-	relay.RejectFilter = append(relay.RejectFilter, plugins.NoComplexFilters)
+	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) {
+	// you can request auth by rejecting an event or a request with the prefix "auth-required: "
-			// request NIP-42 AUTH from everybody
+	relay.RejectFilter = append(relay.RejectFilter,
-			relay.RequestAuth(ctx)
+		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!")
 		},
 	)

go.mod

@@ -5,7 +5,7 @@ go 1.21.0
 require (
 	github.com/fasthttp/websocket v1.5.3
 	github.com/fiatjaf/eventstore v0.1.0
-	github.com/nbd-wtf/go-nostr v0.25.7
+	github.com/nbd-wtf/go-nostr v0.26.0
 	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 v0.25.7 h1:DcGOSgKVr/L6w62tRtKeV2t46sRyFcq9pWcyIFkh0eM=
+github.com/nbd-wtf/go-nostr v0.26.0 h1:Tofbs9i8DD5iEKIhLlWFO7kfWpvmUG16fEyW30MzHVQ=
-github.com/nbd-wtf/go-nostr v0.25.7/go.mod h1:bkffJI+x914sPQWum9ZRUn66D7NpDnAoWo1yICvj3/0=
+github.com/nbd-wtf/go-nostr v0.26.0/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

@@ -6,6 +6,7 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"strings"
 	"sync"
@@ -14,22 +15,25 @@ import (
 	"github.com/fasthttp/websocket"
 	"github.com/nbd-wtf/go-nostr"
 	"github.com/nbd-wtf/go-nostr/nip42"
+	"github.com/rs/cors"
 )
 
 // 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" {
-		rl.HandleNIP11(w, r)
+		cors.AllowAll().Handler(http.HandlerFunc(rl.HandleNIP11)).ServeHTTP(w, r)
 	} else {
 		rl.serveMux.ServeHTTP(w, r)
 	}
 }
 
 func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
-	ctx := r.Context()
-
 	conn, err := rl.upgrader.Upgrade(w, r, nil)
 	if err != nil {
 		rl.Log.Printf("failed to upgrade websocket: %v\n", err)
@@ -43,21 +47,31 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 	rand.Read(challenge)
 
 	ws := &WebSocket{
-		conn:           conn,
+		conn:      conn,
-		Challenge:      hex.EncodeToString(challenge),
+		Request:   r,
-		WaitingForAuth: make(chan struct{}),
+		Challenge: hex.EncodeToString(challenge),
+		Authed:    make(chan struct{}),
+	}
+
+	ctx, cancel := context.WithCancel(
+		context.WithValue(
+			context.Background(),
+			WS_KEY, ws,
+		),
+	)
+
+	kill := func() {
+		ticker.Stop()
+		cancel()
+		if _, ok := rl.clients.Load(conn); ok {
+			conn.Close()
+			rl.clients.Delete(conn)
+			removeListener(ws)
+		}
 	}
 
-	// reader
 	go func() {
-		defer func() {
+		defer kill()
-			ticker.Stop()
-			if _, ok := rl.clients.Load(conn); ok {
-				conn.Close()
-				rl.clients.Delete(conn)
-				removeListener(ws)
-			}
-		}()
 
 		conn.SetReadLimit(rl.MaxMessageSize)
 		conn.SetReadDeadline(time.Now().Add(rl.PongWait))
@@ -75,6 +89,7 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 			if err != nil {
 				if websocket.IsUnexpectedCloseError(
 					err,
+					websocket.CloseNormalClosure,    // 1000
 					websocket.CloseGoingAway,        // 1001
 					websocket.CloseNoStatusReceived, // 1005
 					websocket.CloseAbnormalClosure,  // 1006
@@ -90,152 +105,113 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 			}
 
 			go func(message []byte) {
-				ctx = context.Background()
+				envelope := nostr.ParseMessage(message)
-
+				if envelope == nil {
-				var request []json.RawMessage
-				if err := json.Unmarshal(message, &request); err != nil {
 					// stop silently
 					return
 				}
 
-				if len(request) < 2 {
+				switch env := envelope.(type) {
-					ws.WriteJSON(nostr.NoticeEnvelope("request has less than 2 parameters"))
+				case *nostr.EventEnvelope:
-					return
+					// check id
-				}
+					hash := sha256.Sum256(env.Event.Serialize())
-
+					id := hex.EncodeToString(hash[:])
-				var typ string
+					if id != env.Event.ID {
-				json.Unmarshal(request[0], &typ)
+						ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: false, Reason: "invalid: id is computed incorrectly"})
-
-				switch typ {
-				case "EVENT":
-					// it's a new event
-					var evt nostr.Event
-					if err := json.Unmarshal(request[1], &evt); err != nil {
-						ws.WriteJSON(nostr.NoticeEnvelope("failed to decode event: " + err.Error()))
 						return
 					}
 
-					// check serialization
+					// check signature
-					serialized := evt.Serialize()
+					if ok, err := env.Event.CheckSignature(); err != nil {
-
+						ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: false, Reason: "error: failed to verify signature"})
-					// assign ID
-					hash := sha256.Sum256(serialized)
-					evt.ID = hex.EncodeToString(hash[:])
-
-					// check signature (requires the ID to be set)
-					if ok, err := evt.CheckSignature(); err != nil {
-						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "error: failed to verify signature"})
 						return
 					} else if !ok {
-						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "invalid: signature is invalid"})
+						ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: false, Reason: "invalid: signature is invalid"})
 						return
 					}
 
 					var ok bool
-					if evt.Kind == 5 {
+					if env.Event.Kind == 5 {
-						err = rl.handleDeleteRequest(ctx, &evt)
+						err = rl.handleDeleteRequest(ctx, &env.Event)
 					} else {
-						err = rl.AddEvent(ctx, &evt)
+						err = rl.AddEvent(ctx, &env.Event)
 					}
 
 					var reason string
 					if err == nil {
 						ok = true
 					} else {
-						reason = err.Error()
+						reason = nostr.NormalizeOKMessage(err.Error(), "blocked")
+						if isAuthRequired(reason) {
+							ws.WriteJSON(nostr.AuthEnvelope{Challenge: &ws.Challenge})
+						}
 					}
-					ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: ok, Reason: reason})
+					ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: ok, Reason: reason})
-				case "COUNT":
+				case *nostr.CountEnvelope:
 					if rl.CountEvents == nil {
-						ws.WriteJSON(nostr.NoticeEnvelope("this relay does not support NIP-45"))
+						ws.WriteJSON(nostr.ClosedEnvelope{SubscriptionID: env.SubscriptionID, Reason: "unsupported: this relay does not support NIP-45"})
 						return
 					}
-
-					var id string
-					json.Unmarshal(request[1], &id)
-					if id == "" {
-						ws.WriteJSON(nostr.NoticeEnvelope("COUNT has no <id>"))
-						return
-					}
-
 					var total int64
-					filters := make(nostr.Filters, len(request)-2)
+					for _, filter := range env.Filters {
-					for i, filterReq := range request[2:] {
+						total += rl.handleCountRequest(ctx, ws, filter)
-						if err := json.Unmarshal(filterReq, &filters[i]); err != nil {
-							ws.WriteJSON(nostr.NoticeEnvelope("failed to decode filter"))
-							continue
-						}
-						total += rl.handleCountRequest(ctx, ws, filters[i])
 					}
-
+					ws.WriteJSON(nostr.CountEnvelope{SubscriptionID: env.SubscriptionID, Count: &total})
-					ws.WriteJSON([]interface{}{"COUNT", id, map[string]int64{"count": total}})
+				case *nostr.ReqEnvelope:
-				case "REQ":
-					var id string
-					json.Unmarshal(request[1], &id)
-					if id == "" {
-						ws.WriteJSON(nostr.NoticeEnvelope("REQ has no <id>"))
-						return
-					}
-
-					filters := make(nostr.Filters, len(request)-2)
 					eose := sync.WaitGroup{}
-					eose.Add(len(request[2:]))
+					eose.Add(len(env.Filters))
 
-					for i, filterReq := range request[2:] {
+					// a context just for the "stored events" request handler
-						if err := json.Unmarshal(filterReq, &filters[i]); err != nil {
+					reqCtx, cancelReqCtx := context.WithCancelCause(ctx)
-							ws.WriteJSON(nostr.NoticeEnvelope("failed to decode filter"))
+
-							eose.Done()
+					// handle each filter separately -- dispatching events as they're loaded from databases
-							continue
+					for _, filter := range env.Filters {
+						err := rl.handleRequest(reqCtx, env.SubscriptionID, &eose, ws, filter)
+						if err != nil {
+							// fail everything if any filter is rejected
+							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})
+							cancelReqCtx(fmt.Errorf("filter rejected"))
+							return
 						}
-
-						go rl.handleRequest(ctx, id, &eose, ws, filters[i])
 					}
 
 					go func() {
+						// when all events have been loaded from databases and dispatched
+						// we can cancel the context and fire the EOSE message
 						eose.Wait()
-						ws.WriteJSON(nostr.EOSEEnvelope(id))
+						cancelReqCtx(nil)
+						ws.WriteJSON(nostr.EOSEEnvelope(env.SubscriptionID))
 					}()
 
-					setListener(id, ws, filters)
+					setListener(env.SubscriptionID, ws, env.Filters, cancelReqCtx)
-				case "CLOSE":
+				case *nostr.CloseEnvelope:
-					var id string
+					removeListenerId(ws, string(*env))
-					json.Unmarshal(request[1], &id)
+				case *nostr.AuthEnvelope:
-					if id == "" {
+					wsBaseUrl := strings.Replace(rl.ServiceURL, "http", "ws", 1)
-						ws.WriteJSON(nostr.NoticeEnvelope("CLOSE has no <id>"))
+					if pubkey, ok := nip42.ValidateAuthEvent(&env.Event, ws.Challenge, wsBaseUrl); ok {
-						return
+						ws.AuthedPublicKey = pubkey
-					}
+						close(ws.Authed)
-
+						ctx = context.WithValue(ctx, AUTH_CONTEXT_KEY, pubkey)
-					removeListenerId(ws, id)
+						ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: true})
-				case "AUTH":
+					} else {
-					if rl.ServiceURL != "" {
+						ws.WriteJSON(nostr.OKEnvelope{EventID: env.Event.ID, OK: false, Reason: "error: failed to authenticate"})
-						var evt nostr.Event
-						if err := json.Unmarshal(request[1], &evt); err != nil {
-							ws.WriteJSON(nostr.NoticeEnvelope("failed to decode auth event: " + err.Error()))
-							return
-						}
-						if pubkey, ok := nip42.ValidateAuthEvent(&evt, ws.Challenge, rl.ServiceURL); ok {
-							ws.Authed = pubkey
-							close(ws.WaitingForAuth)
-							ctx = context.WithValue(ctx, AUTH_CONTEXT_KEY, pubkey)
-							ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: true})
-						} else {
-							ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "error: failed to authenticate"})
-						}
 					}
 				}
 			}(message)
 		}
 	}()
 
-	// writer
 	go func() {
-		defer func() {
+		defer kill()
-			ticker.Stop()
-			conn.Close()
-		}()
 
 		for {
 			select {
+			case <-ctx.Done():
+				return
 			case <-ticker.C:
 				err := ws.WriteMessage(websocket.PingMessage, nil)
 				if err != nil {
@@ -251,5 +227,11 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 
 func (rl *Relay) HandleNIP11(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/nostr+json")
-	json.NewEncoder(w).Encode(rl.Info)
+
+	info := *rl.Info
+	for _, ovw := range rl.OverwriteRelayInformation {
+		info = ovw(r.Context(), r, info)
+	}
+
+	json.NewEncoder(w).Encode(info)
 }

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
+}

listener.go

@@ -1,12 +1,16 @@
 package khatru
 
 import (
+	"context"
+	"fmt"
+
 	"github.com/nbd-wtf/go-nostr"
 	"github.com/puzpuzpuz/xsync/v2"
 )
 
 type Listener struct {
 	filters nostr.Filters
+	cancel  context.CancelCauseFunc
 }
 
 var listeners = xsync.NewTypedMapOf[*WebSocket, *xsync.MapOf[string, *Listener]](pointerHasher[WebSocket])
@@ -43,24 +47,28 @@ func GetListeningFilters() nostr.Filters {
 	return respfilters
 }
 
-func setListener(id string, ws *WebSocket, filters nostr.Filters) {
+func setListener(id string, ws *WebSocket, filters nostr.Filters, cancel context.CancelCauseFunc) {
 	subs, _ := listeners.LoadOrCompute(ws, func() *xsync.MapOf[string, *Listener] {
 		return xsync.NewMapOf[*Listener]()
 	})
-	subs.Store(id, &Listener{filters: filters})
+	subs.Store(id, &Listener{filters: filters, cancel: cancel})
 }
 
-// Remove a specific subscription id from listeners for a given ws client
+// remove a specific subscription id from listeners for a given ws client
+// and cancel its specific context
 func removeListenerId(ws *WebSocket, id string) {
 	if subs, ok := listeners.Load(ws); ok {
-		subs.Delete(id)
+		if listener, ok := subs.LoadAndDelete(id); ok {
+			listener.cancel(fmt.Errorf("subscription closed by client"))
+		}
 		if subs.Size() == 0 {
 			listeners.Delete(ws)
 		}
 	}
 }
 
-// Remove WebSocket conn from listeners
+// remove WebSocket conn from listeners
+// (no need to cancel contexts as they are all inherited from the main connection context)
 func removeListener(ws *WebSocket) {
 	listeners.Delete(ws)
 }

policies/events.go

@@ -1,15 +1,37 @@
-package plugins
+package policies
 
 import (
 	"context"
 
 	"github.com/nbd-wtf/go-nostr"
+	"golang.org/x/exp/slices"
 )
 
 // PreventTooManyIndexableTags returns a function that can be used as a RejectFilter that will reject
 // events with more indexable (single-character) tags than the specified number.
-func PreventTooManyIndexableTags(max int) func(context.Context, *nostr.Event) (bool, string) {
+//
+// If ignoreKinds is given this restriction will not apply to these kinds (useful for allowing a bigger).
+// If onlyKinds is given then all other kinds will be ignored.
+func PreventTooManyIndexableTags(max int, ignoreKinds []int, onlyKinds []int) func(context.Context, *nostr.Event) (bool, string) {
+	ignore := func(kind int) bool { return false }
+	if len(ignoreKinds) > 0 {
+		ignore = func(kind int) bool {
+			_, isIgnored := slices.BinarySearch(ignoreKinds, kind)
+			return isIgnored
+		}
+	}
+	if len(onlyKinds) > 0 {
+		ignore = func(kind int) bool {
+			_, isApplicable := slices.BinarySearch(onlyKinds, kind)
+			return !isApplicable
+		}
+	}
+
 	return func(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+		if ignore(event.Kind) {
+			return false, ""
+		}
+
 		ntags := 0
 		for _, tag := range event.Tags {
 			if len(tag) > 0 && len(tag[0]) == 1 {
@@ -42,9 +64,7 @@ func PreventLargeTags(maxTagValueLen int) func(context.Context, *nostr.Event) (b
 func RestrictToSpecifiedKinds(kinds ...uint16) func(context.Context, *nostr.Event) (bool, string) {
 	max := 0
 	min := 0
-	allowed := make(map[uint16]struct{}, len(kinds))
 	for _, kind := range kinds {
-		allowed[kind] = struct{}{}
 		if int(kind) > max {
 			max = int(kind)
 		}
@@ -64,7 +84,7 @@ func RestrictToSpecifiedKinds(kinds ...uint16) func(context.Context, *nostr.Even
 		}
 
 		// hopefully this map of uint16s is very fast
-		if _, allowed := allowed[uint16(event.Kind)]; allowed {
+		if _, allowed := slices.BinarySearch(kinds, uint16(event.Kind)); allowed {
 			return false, ""
 		}
 		return true, "event kind not allowed"

policies/filters.go

@@ -1,4 +1,4 @@
-package plugins
+package policies
 
 import (
 	"context"
@@ -7,6 +7,7 @@ import (
 	"golang.org/x/exp/slices"
 )
 
+// NoComplexFilters disallows filters with more than 2 tags.
 func NoComplexFilters(ctx context.Context, filter nostr.Filter) (reject bool, msg string) {
 	items := len(filter.Tags) + len(filter.Kinds)
 
@@ -17,6 +18,7 @@ func NoComplexFilters(ctx context.Context, filter nostr.Filter) (reject bool, ms
 	return false, ""
 }
 
+// NoEmptyFilters disallows filters that don't have at least a tag, a kind, an author or an id.
 func NoEmptyFilters(ctx context.Context, filter nostr.Filter) (reject bool, msg string) {
 	c := len(filter.Kinds) + len(filter.IDs) + len(filter.Authors)
 	for _, tagItems := range filter.Tags {
@@ -28,6 +30,13 @@ func NoEmptyFilters(ctx context.Context, filter nostr.Filter) (reject bool, msg
 	return false, ""
 }
 
+// AntiSyncBots tries to prevent people from syncing kind:1s from this relay to else by always
+// requiring an author parameter at least.
+func AntiSyncBots(ctx context.Context, filter nostr.Filter) (reject bool, msg string) {
+	return (len(filter.Kinds) == 0 || slices.Contains(filter.Kinds, 1)) &&
+		len(filter.Authors) == 0, "an author must be specified to get their kind:1 notes"
+}
+
 func NoSearchQueries(ctx context.Context, filter nostr.Filter) (reject bool, msg string) {
 	if filter.Search != "" {
 		return true, "search is not supported"

policies/nip04.go

@@ -1,4 +1,4 @@
-package plugins
+package policies
 
 import (
 	"context"
@@ -8,7 +8,8 @@ import (
 	"golang.org/x/exp/slices"
 )
 
-func rejectKind04Snoopers(ctx context.Context, filter nostr.Filter) (bool, string) {
+// RejectKind04Snoopers prevents reading NIP-04 messages from people not involved in the conversation.
+func RejectKind04Snoopers(ctx context.Context, filter nostr.Filter) (bool, string) {
 	// prevent kind-4 events from being returned to unauthed users,
 	//   only when authentication is a thing
 	if !slices.Contains(filter.Kinds, 4) {
@@ -19,13 +20,13 @@ func rejectKind04Snoopers(ctx context.Context, filter nostr.Filter) (bool, strin
 	senders := filter.Authors
 	receivers, _ := filter.Tags["p"]
 	switch {
-	case ws.Authed == "":
+	case ws.AuthedPublicKey == "":
 		// not authenticated
 		return true, "restricted: this relay does not serve kind-4 to unauthenticated users, does your client implement NIP-42?"
-	case len(senders) == 1 && len(receivers) < 2 && (senders[0] == ws.Authed):
+	case len(senders) == 1 && len(receivers) < 2 && (senders[0] == ws.AuthedPublicKey):
 		// allowed filter: ws.authed is sole sender (filter specifies one or all receivers)
 		return false, ""
-	case len(receivers) == 1 && len(senders) < 2 && (receivers[0] == ws.Authed):
+	case len(receivers) == 1 && len(senders) < 2 && (receivers[0] == ws.AuthedPublicKey):
 		// allowed filter: ws.authed is sole receiver (filter specifies one or all senders)
 		return false, ""
 	default:

relay.go

@@ -18,8 +18,9 @@ func NewRelay() *Relay {
 		Log: log.New(os.Stderr, "[khatru-relay] ", log.LstdFlags),
 
 		Info: &nip11.RelayInformationDocument{
-			Software: "https://github.com/fiatjaf/khatru",
+			Software:      "https://github.com/fiatjaf/khatru",
-			Version:  "n/a",
+			Version:       "n/a",
+			SupportedNIPs: make([]int, 0),
 		},
 
 		upgrader: websocket.Upgrader{
@@ -39,22 +40,23 @@ 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)
+	RejectEvent               []func(ctx context.Context, event *nostr.Event) (reject bool, msg string)
-	RejectFilter             []func(ctx context.Context, filter nostr.Filter) (reject bool, msg string)
+	RejectFilter              []func(ctx context.Context, filter nostr.Filter) (reject bool, msg string)
-	RejectCountFilter        []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)
+	OverwriteDeletionOutcome  []func(ctx context.Context, target *nostr.Event, deletion *nostr.Event) (acceptDeletion bool, msg string)
-	OverwriteResponseEvent   []func(ctx context.Context, event *nostr.Event)
+	OverwriteResponseEvent    []func(ctx context.Context, event *nostr.Event)
-	OverwriteFilter          []func(ctx context.Context, filter *nostr.Filter)
+	OverwriteFilter           []func(ctx context.Context, filter *nostr.Filter)
-	OverwriteCountFilter     []func(ctx context.Context, filter *nostr.Filter)
+	OverwriteCountFilter      []func(ctx context.Context, filter *nostr.Filter)
-	StoreEvent               []func(ctx context.Context, event *nostr.Event) error
+	OverwriteRelayInformation []func(ctx context.Context, r *http.Request, info nip11.RelayInformationDocument) nip11.RelayInformationDocument
-	DeleteEvent              []func(ctx context.Context, event *nostr.Event) error
+	StoreEvent                []func(ctx context.Context, event *nostr.Event) error
-	QueryEvents              []func(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error)
+	DeleteEvent               []func(ctx context.Context, event *nostr.Event) error
-	CountEvents              []func(ctx context.Context, filter nostr.Filter) (int64, error)
+	QueryEvents               []func(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error)
-	OnAuth                   []func(ctx context.Context, pubkey string)
+	CountEvents               []func(ctx context.Context, filter nostr.Filter) (int64, error)
-	OnConnect                []func(ctx context.Context)
+	OnAuth                    []func(ctx context.Context, pubkey string)
-	OnEventSaved             []func(ctx context.Context, event *nostr.Event)
+	OnConnect                 []func(ctx context.Context)
+	OnEventSaved              []func(ctx context.Context, event *nostr.Event)
 
 	// editing info will affect
 	Info *nip11.RelayInformationDocument
@@ -80,8 +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})
-}

serve-req.go

@@ -2,12 +2,13 @@ package khatru
 
 import (
 	"context"
+	"fmt"
 	"sync"
 
 	"github.com/nbd-wtf/go-nostr"
 )
 
-func (rl *Relay) handleRequest(ctx context.Context, id string, eose *sync.WaitGroup, ws *WebSocket, filter nostr.Filter) {
+func (rl *Relay) handleRequest(ctx context.Context, id string, eose *sync.WaitGroup, ws *WebSocket, filter nostr.Filter) error {
 	defer eose.Done()
 
 	// overwrite the filter (for example, to eliminate some kinds or
@@ -17,7 +18,7 @@ func (rl *Relay) handleRequest(ctx context.Context, id string, eose *sync.WaitGr
 	}
 
 	if filter.Limit < 0 {
-		return
+		return fmt.Errorf("filter invalidated")
 	}
 
 	// then check if we'll reject this filter (we apply this after overwriting
@@ -27,7 +28,7 @@ func (rl *Relay) handleRequest(ctx context.Context, id string, eose *sync.WaitGr
 	for _, reject := range rl.RejectFilter {
 		if reject, msg := reject(ctx, filter); reject {
 			ws.WriteJSON(nostr.NoticeEnvelope(msg))
-			return
+			return fmt.Errorf(msg)
 		}
 	}
 
@@ -52,6 +53,8 @@ func (rl *Relay) handleRequest(ctx context.Context, id string, eose *sync.WaitGr
 			eose.Done()
 		}(ch)
 	}
+
+	return nil
 }
 
 func (rl *Relay) handleCountRequest(ctx context.Context, ws *WebSocket, filter nostr.Filter) int64 {

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)
-}

websocket.go

@@ -1,6 +1,7 @@
 package khatru
 
 import (
+	"net/http"
 	"sync"
 
 	"github.com/fasthttp/websocket"
@@ -10,10 +11,13 @@ type WebSocket struct {
 	conn  *websocket.Conn
 	mutex sync.Mutex
 
+	// original request
+	Request *http.Request
+
 	// nip42
-	Challenge      string
+	Challenge       string
-	Authed         string
+	AuthedPublicKey string
-	WaitingForAuth chan struct{}
+	Authed          chan struct{}
 }
 
 func (ws *WebSocket) WriteJSON(any any) error {