OverwriteRelayInformation

.github/workflows/test.yml

@@ -0,0 +1,14 @@
+name: test every commit
+on:
+  - push
+  - pull_request
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-go@v3
+        with:
+          go-version-file: ./go.mod
+      - run: go test ./...

README.md

@@ -1 +1,120 @@
-khatru
+# khatru, a relay framework [![docs badge](https://img.shields.io/badge/docs-reference-blue)](https://pkg.go.dev/github.com/fiatjaf/khatru#Relay)
+
+[![Run Tests](https://github.com/fiatjaf/khatru/actions/workflows/test.yml/badge.svg)](https://github.com/fiatjaf/khatru/actions/workflows/test.yml)
+[![Go Reference](https://pkg.go.dev/badge/github.com/fiatjaf/khatru.svg)](https://pkg.go.dev/github.com/fiatjaf/khatru)
+[![Go Report Card](https://goreportcard.com/badge/github.com/fiatjaf/khatru)](https://goreportcard.com/report/github.com/fiatjaf/khatru)
+
+Khatru makes it easy to write very very custom relays:
+
+  - custom event or filter acceptance policies
+  - custom `AUTH` handlers
+  - custom storage and pluggable databases
+  - custom webpages and other HTTP handlers
+
+Here's a sample:
+
+```go
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/fiatjaf/khatru"
+	"github.com/nbd-wtf/go-nostr"
+)
+
+func main() {
+	// create the relay instance
+	relay := khatru.NewRelay()
+
+	// set up some basic properties (will be returned on the NIP-11 endpoint)
+	relay.Info.Name = "my relay"
+	relay.Info.PubKey = "79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798"
+	relay.Info.Description = "this is my custom relay"
+	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)
+
+	// set up the basic relay functions
+	relay.StoreEvent = append(relay.StoreEvent,
+		func(ctx context.Context, event *nostr.Event) error {
+			store[event.ID] = event
+			return nil
+		},
+	)
+	relay.QueryEvents = append(relay.QueryEvents,
+		func(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
+			ch := make(chan *nostr.Event)
+			go func() {
+				for _, evt := range store {
+					if filter.Matches(evt) {
+						ch <- evt
+					}
+				}
+				close(ch)
+			}()
+			return ch, nil
+		},
+	)
+	relay.DeleteEvent = append(relay.DeleteEvent,
+		func(ctx context.Context, event *nostr.Event) error {
+			delete(store, event.ID)
+			return nil
+		},
+	)
+
+	// there are many other configurable things you can set
+	relay.RejectEvent = append(relay.RejectEvent,
+		func(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+			if event.PubKey == "fa984bd7dbb282f07e16e7ae87b26a2a7b9b90b7246a44771f0cf5ae58018f52" {
+				return true, "we don't allow this person to write here"
+			}
+			return false, "" // anyone else can
+		},
+	)
+	relay.OnConnect = append(relay.OnConnect,
+		func(ctx context.Context) {
+			// request NIP-42 AUTH from everybody
+			relay.RequestAuth(ctx)
+		},
+	)
+	relay.OnAuth = append(relay.OnAuth,
+		func(ctx context.Context, pubkey string) {
+			// and when they auth we just log that for nothing
+			log.Println(pubkey + " is authed!")
+		},
+	)
+	// check the docs for more goodies!
+
+	mux := relay.Router()
+	// set up other http handlers
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("content-type", "text/html")
+		fmt.Fprintf(w, `<b>welcome</b> to my relay!`)
+	})
+
+	// start the server
+	fmt.Println("running on :3334")
+	http.ListenAndServe(":3334", relay)
+}
+```
+
+### But I don't want to write my own database!
+
+Fear no more. Using the https://github.com/fiatjaf/eventstore module you get a bunch of compatible databases out of the box and you can just plug them into your relay. For example, [sqlite](https://pkg.go.dev/github.com/fiatjaf/eventstore/sqlite3):
+
+```go
+	db := sqlite3.SQLite3Backend{DatabaseURL: "/tmp/khatru-sqlite-tmp"}
+	if err := db.Init(); err != nil {
+		panic(err)
+	}
+
+	relay.StoreEvent = append(relay.StoreEvent, db.SaveEvent)
+	relay.QueryEvents = append(relay.QueryEvents, db.QueryEvents)
+	relay.CountEvents = append(relay.CountEvents, db.CountEvents)
+	relay.DeleteEvent = append(relay.DeleteEvent, db.DeleteEvent)
+```

add-event.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/fiatjaf/eventstore"
 	"github.com/nbd-wtf/go-nostr"
 )
 
@@ -12,22 +13,15 @@ func (rl *Relay) AddEvent(ctx context.Context, evt *nostr.Event) error {
 		return fmt.Errorf("event is nil")
 	}
 
-	msg := ""
-	rejecting := false
 	for _, reject := range rl.RejectEvent {
-		rejecting, msg = reject(ctx, evt)
+		if reject, msg := reject(ctx, evt); reject {
-		if rejecting {
+			if msg == "" {
-			break
+				msg = "no reason"
+			}
+			return fmt.Errorf(msg)
 		}
 	}
 
-	if rejecting {
-		if msg == "" {
-			msg = "no reason"
-		}
-		return fmt.Errorf(msg)
-	}
-
 	if 20000 <= evt.Kind && evt.Kind < 30000 {
 		// do not store ephemeral events
 	} else {
@@ -38,8 +32,7 @@ func (rl *Relay) AddEvent(ctx context.Context, evt *nostr.Event) error {
 				if err != nil {
 					continue
 				}
-				previous := <-ch
+				if previous := <-ch; previous != nil && isOlder(previous, evt) {
-				if previous != nil {
 					for _, del := range rl.DeleteEvent {
 						del(ctx, previous)
 					}
@@ -54,8 +47,7 @@ func (rl *Relay) AddEvent(ctx context.Context, evt *nostr.Event) error {
 					if err != nil {
 						continue
 					}
-					previous := <-ch
+					if previous := <-ch; previous != nil && isOlder(previous, evt) {
-					if previous != nil {
 						for _, del := range rl.DeleteEvent {
 							del(ctx, previous)
 						}
@@ -68,7 +60,7 @@ func (rl *Relay) AddEvent(ctx context.Context, evt *nostr.Event) error {
 		for _, store := range rl.StoreEvent {
 			if saveErr := store(ctx, evt); saveErr != nil {
 				switch saveErr {
-				case ErrDupEvent:
+				case eventstore.ErrDupEvent:
 					return nil
 				default:
 					errmsg := saveErr.Error()
@@ -86,7 +78,11 @@ func (rl *Relay) AddEvent(ctx context.Context, evt *nostr.Event) error {
 		}
 	}
 
+	for _, ovw := range rl.OverwriteResponseEvent {
+		ovw(ctx, evt)
+	}
 	notifyListeners(evt)
+
 	return nil
 }
 

errors.go

@@ -1,5 +0,0 @@
-package khatru
-
-import "fmt"
-
-var ErrDupEvent = fmt.Errorf("duplicate: event already exists")

examples/exclusive/main.go

@@ -27,7 +27,7 @@ func main() {
 	relay.DeleteEvent = append(relay.DeleteEvent, db.DeleteEvent)
 
 	relay.RejectEvent = append(relay.RejectEvent, plugins.PreventTooManyIndexableTags(10))
-	relay.RejectFilter = append(relay.RejectFilter, plugins.NoPrefixFilters, plugins.NoComplexFilters)
+	relay.RejectFilter = append(relay.RejectFilter, plugins.NoComplexFilters)
 
 	relay.OnEventSaved = append(relay.OnEventSaved, func(ctx context.Context, event *nostr.Event) {
 	})

examples/readme-demo/main.go

@@ -0,0 +1,87 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/fiatjaf/khatru"
+	"github.com/nbd-wtf/go-nostr"
+)
+
+func main() {
+	// create the relay instance
+	relay := khatru.NewRelay()
+
+	// set up some basic properties (will be returned on the NIP-11 endpoint)
+	relay.Info.Name = "my relay"
+	relay.Info.PubKey = "79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798"
+	relay.Info.Description = "this is my custom relay"
+	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)
+
+	// set up the basic relay functions
+	relay.StoreEvent = append(relay.StoreEvent,
+		func(ctx context.Context, event *nostr.Event) error {
+			store[event.ID] = event
+			return nil
+		},
+	)
+	relay.QueryEvents = append(relay.QueryEvents,
+		func(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
+			ch := make(chan *nostr.Event)
+			go func() {
+				for _, evt := range store {
+					if filter.Matches(evt) {
+						ch <- evt
+					}
+				}
+				close(ch)
+			}()
+			return ch, nil
+		},
+	)
+	relay.DeleteEvent = append(relay.DeleteEvent,
+		func(ctx context.Context, event *nostr.Event) error {
+			delete(store, event.ID)
+			return nil
+		},
+	)
+
+	// there are many other configurable things you can set
+	relay.RejectEvent = append(relay.RejectEvent,
+		func(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+			if event.PubKey == "fa984bd7dbb282f07e16e7ae87b26a2a7b9b90b7246a44771f0cf5ae58018f52" {
+				return true, "we don't allow this person to write here"
+			}
+			return false, "" // anyone else can
+		},
+	)
+	relay.OnConnect = append(relay.OnConnect,
+		func(ctx context.Context) {
+			// request NIP-42 AUTH from everybody
+			relay.RequestAuth(ctx)
+		},
+	)
+	relay.OnAuth = append(relay.OnAuth,
+		func(ctx context.Context, pubkey string) {
+			// and when they auth we just log that for nothing
+			log.Println(pubkey + " is authed!")
+		},
+	)
+	// check the docs for more goodies!
+
+	mux := relay.Router()
+	// set up other http handlers
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("content-type", "text/html")
+		fmt.Fprintf(w, `<b>welcome</b> to my relay!`)
+	})
+
+	// start the server
+	fmt.Println("running on :3334")
+	http.ListenAndServe(":3334", relay)
+}

go.mod

@@ -5,8 +5,7 @@ go 1.21.0
 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 v0.25.7
-	github.com/nbd-wtf/go-nostr v0.25.0
 	github.com/puzpuzpuz/xsync/v2 v2.5.1
 	github.com/rs/cors v1.7.0
 	golang.org/x/exp v0.0.0-20230425010034-47ecfdc1ba53
@@ -30,6 +29,7 @@ require (
 	github.com/fatih/structs v1.1.0 // indirect
 	github.com/gobwas/httphead v0.1.0 // indirect
 	github.com/gobwas/pool v0.2.1 // indirect
+	github.com/gobwas/ws v1.2.0 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/glog v1.0.0 // indirect
 	github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6 // indirect

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 v0.25.7 h1:DcGOSgKVr/L6w62tRtKeV2t46sRyFcq9pWcyIFkh0eM=
-github.com/nbd-wtf/go-nostr v0.25.0/go.mod h1:bkffJI+x914sPQWum9ZRUn66D7NpDnAoWo1yICvj3/0=
+github.com/nbd-wtf/go-nostr v0.25.7/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

@@ -7,13 +7,14 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"net/http"
+	"strings"
 	"sync"
 	"time"
 
 	"github.com/fasthttp/websocket"
 	"github.com/nbd-wtf/go-nostr"
-	"github.com/nbd-wtf/go-nostr/nip11"
 	"github.com/nbd-wtf/go-nostr/nip42"
+	"github.com/rs/cors"
 )
 
 // ServeHTTP implements http.Handler interface.
@@ -21,7 +22,7 @@ func (rl *Relay) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	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)
 	}
@@ -48,6 +49,8 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 		WaitingForAuth: make(chan struct{}),
 	}
 
+	ctx = context.WithValue(ctx, WS_KEY, ws)
+
 	// reader
 	go func() {
 		defer func() {
@@ -75,6 +78,7 @@ 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
@@ -115,21 +119,20 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 						return
 					}
 
-					// check serialization
+					// check id
-					serialized := evt.Serialize()
+					hash := sha256.Sum256(evt.Serialize())
+					id := hex.EncodeToString(hash[:])
+					if id != evt.ID {
+						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "invalid: id is computed incorrectly"})
+						return
+					}
 
-					// assign ID
+					// check signature
-					hash := sha256.Sum256(serialized)
-					evt.ID = hex.EncodeToString(hash[:])
-
-					// 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: "error: failed to verify signature"})
-						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: &reason})
 						return
 					} else if !ok {
-						reason := "invalid: signature is invalid"
+						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "invalid: signature is invalid"})
-						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: &reason})
 						return
 					}
 
@@ -139,12 +142,12 @@ 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 = err.Error()
-						reason = &msg
 					}
 					ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: ok, Reason: reason})
 				case "COUNT":
@@ -167,29 +170,7 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 							ws.WriteJSON(nostr.NoticeEnvelope("failed to decode filter"))
 							continue
 						}
-
+						total += rl.handleCountRequest(ctx, ws, filters[i])
-						filter := filters[i]
-
-						for _, reject := range rl.RejectFilter {
-							if rejecting, msg := reject(ctx, filter); rejecting {
-								ws.WriteJSON(nostr.NoticeEnvelope(msg))
-								continue
-							}
-						}
-						for _, reject := range rl.RejectCountFilter {
-							if rejecting, msg := reject(ctx, filter); rejecting {
-								ws.WriteJSON(nostr.NoticeEnvelope(msg))
-								continue
-							}
-						}
-
-						for _, count := range rl.CountEvents {
-							res, err := count(ctx, filter)
-							if err != nil {
-								ws.WriteJSON(nostr.NoticeEnvelope(err.Error()))
-							}
-							total += res
-						}
 					}
 
 					ws.WriteJSON([]interface{}{"COUNT", id, map[string]int64{"count": total}})
@@ -206,43 +187,13 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 					eose.Add(len(request[2:]))
 
 					for i, filterReq := range request[2:] {
-						if err := json.Unmarshal(
+						if err := json.Unmarshal(filterReq, &filters[i]); err != nil {
-							filterReq,
-							&filters[i],
-						); err != nil {
 							ws.WriteJSON(nostr.NoticeEnvelope("failed to decode filter"))
 							eose.Done()
 							continue
 						}
 
-						filter := filters[i]
+						go rl.handleRequest(ctx, id, &eose, ws, filters[i])
-
-						for _, reject := range rl.RejectCountFilter {
-							if rejecting, msg := reject(ctx, filter); rejecting {
-								ws.WriteJSON(nostr.NoticeEnvelope(msg))
-								eose.Done()
-								continue
-							}
-						}
-
-						eose.Add(len(rl.QueryEvents))
-						for _, query := range rl.QueryEvents {
-							ch, err := query(ctx, filter)
-							if err != nil {
-								ws.WriteJSON(nostr.NoticeEnvelope(err.Error()))
-								eose.Done()
-								continue
-							}
-
-							go func(ch chan *nostr.Event) {
-								for event := range ch {
-									ws.WriteJSON(nostr.EventEnvelope{SubscriptionID: &id, Event: *event})
-								}
-								eose.Done()
-							}(ch)
-						}
-
-						eose.Done()
 					}
 
 					go func() {
@@ -273,8 +224,7 @@ 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: "error: failed to authenticate"})
-							ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: &reason})
 						}
 					}
 				}
@@ -294,7 +244,9 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 			case <-ticker.C:
 				err := ws.WriteMessage(websocket.PingMessage, nil)
 				if err != nil {
-					rl.Log.Printf("error writing ping: %v; closing websocket\n", err)
+					if !strings.HasSuffix(err.Error(), "use of closed network connection") {
+						rl.Log.Printf("error writing ping: %v; closing websocket\n", err)
+					}
 					return
 				}
 			}
@@ -303,29 +255,11 @@ 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/json")
+	w.Header().Set("Content-Type", "application/nostr+json")
 
-	supportedNIPs := []int{9, 11, 12, 15, 16, 20, 33}
+	info := *rl.Info
-	if rl.ServiceURL != "" {
+	for _, ovw := range rl.OverwriteRelayInformation {
-		supportedNIPs = append(supportedNIPs, 42)
+		info = ovw(r.Context(), r, info)
-	}
-	if rl.CountEvents != nil {
-		supportedNIPs = append(supportedNIPs, 45)
-	}
-
-	info := nip11.RelayInformationDocument{
-		Name:          rl.Name,
-		Description:   rl.Description,
-		PubKey:        rl.PubKey,
-		Contact:       rl.Contact,
-		Icon:          rl.IconURL,
-		SupportedNIPs: supportedNIPs,
-		Software:      "https://github.com/trailriver/khatru",
-		Version:       "n/a",
-	}
-
-	for _, edit := range rl.EditInformation {
-		edit(r.Context(), &info)
 	}
 
 	json.NewEncoder(w).Encode(info)

plugins/events.go

@@ -1,58 +0,0 @@
-package plugins
-
-import (
-	"context"
-
-	"github.com/nbd-wtf/go-nostr"
-)
-
-// 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) {
-	return func(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
-		ntags := 0
-		for _, tag := range event.Tags {
-			if len(tag) > 0 && len(tag[0]) == 1 {
-				ntags++
-			}
-		}
-		if ntags > max {
-			return true, "too many indexable tags"
-		}
-		return false, ""
-	}
-}
-
-// RestrictToSpecifiedKinds returns a function that can be used as a RejectFilter that will reject
-// any events with kinds different than the specified ones.
-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)
-		}
-		if int(kind) < min {
-			min = int(kind)
-		}
-	}
-
-	return func(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
-		// these are cheap and very questionable optimizations, but they exist for a reason:
-		// we would have to ensure that the kind number is within the bounds of a uint16 anyway
-		if event.Kind > max {
-			return true, "event kind not allowed"
-		}
-		if event.Kind < min {
-			return true, "event kind not allowed"
-		}
-
-		// hopefully this map of uint16s is very fast
-		if _, allowed := allowed[uint16(event.Kind)]; allowed {
-			return false, ""
-		}
-		return true, "event kind not allowed"
-	}
-}

plugins/filters.go

@@ -1,33 +0,0 @@
-package plugins
-
-import (
-	"context"
-	"fmt"
-
-	"github.com/nbd-wtf/go-nostr"
-)
-
-func NoPrefixFilters(ctx context.Context, filter nostr.Filter) (reject bool, msg string) {
-	for _, id := range filter.IDs {
-		if len(id) != 64 {
-			return true, fmt.Sprintf("filters can only contain full ids")
-		}
-	}
-	for _, pk := range filter.Authors {
-		if len(pk) != 64 {
-			return true, fmt.Sprintf("filters can only contain full pubkeys")
-		}
-	}
-
-	return false, ""
-}
-
-func NoComplexFilters(ctx context.Context, filter nostr.Filter) (reject bool, msg string) {
-	items := len(filter.Tags) + len(filter.Kinds)
-
-	if items > 4 && len(filter.Tags) > 2 {
-		return true, "too many things to filter for"
-	}
-
-	return false, ""
-}

policies/events.go

@@ -0,0 +1,110 @@
+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.
+//
+// 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 {
+				ntags++
+			}
+		}
+		if ntags > max {
+			return true, "too many indexable tags"
+		}
+		return false, ""
+	}
+}
+
+// PreventLargeTags rejects events that have indexable tag values greater than maxTagValueLen.
+func PreventLargeTags(maxTagValueLen int) func(context.Context, *nostr.Event) (bool, string) {
+	return func(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+		for _, tag := range event.Tags {
+			if len(tag) > 1 && len(tag[0]) == 1 {
+				if len(tag[1]) > maxTagValueLen {
+					return true, "event contains too large tags"
+				}
+			}
+		}
+		return false, ""
+	}
+}
+
+// RestrictToSpecifiedKinds returns a function that can be used as a RejectFilter that will reject
+// any events with kinds different than the specified ones.
+func RestrictToSpecifiedKinds(kinds ...uint16) func(context.Context, *nostr.Event) (bool, string) {
+	max := 0
+	min := 0
+	for _, kind := range kinds {
+		if int(kind) > max {
+			max = int(kind)
+		}
+		if int(kind) < min {
+			min = int(kind)
+		}
+	}
+
+	return func(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+		// these are cheap and very questionable optimizations, but they exist for a reason:
+		// we would have to ensure that the kind number is within the bounds of a uint16 anyway
+		if event.Kind > max {
+			return true, "event kind not allowed"
+		}
+		if event.Kind < min {
+			return true, "event kind not allowed"
+		}
+
+		// hopefully this map of uint16s is very fast
+		if _, allowed := slices.BinarySearch(kinds, uint16(event.Kind)); allowed {
+			return false, ""
+		}
+		return true, "event kind not allowed"
+	}
+}
+
+func PreventTimestampsInThePast(thresholdSeconds nostr.Timestamp) func(context.Context, *nostr.Event) (bool, string) {
+	return func(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+		if nostr.Now()-event.CreatedAt > thresholdSeconds {
+			return true, "event too old"
+		}
+		return false, ""
+	}
+}
+
+func PreventTimestampsInTheFuture(thresholdSeconds nostr.Timestamp) func(context.Context, *nostr.Event) (bool, string) {
+	return func(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+		if event.CreatedAt-nostr.Now() > thresholdSeconds {
+			return true, "event too much in the future"
+		}
+		return false, ""
+	}
+}

policies/filters.go

@@ -0,0 +1,73 @@
+package policies
+
+import (
+	"context"
+
+	"github.com/nbd-wtf/go-nostr"
+	"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)
+
+	if items > 4 && len(filter.Tags) > 2 {
+		return true, "too many things to filter for"
+	}
+
+	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 {
+		c += len(tagItems)
+	}
+	if c == 0 {
+		return true, "can't handle empty filters"
+	}
+	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"
+	}
+	return false, ""
+}
+
+func RemoveSearchQueries(ctx context.Context, filter *nostr.Filter) {
+	filter.Search = ""
+}
+
+func RemoveAllButKinds(kinds ...uint16) func(context.Context, *nostr.Filter) {
+	return func(ctx context.Context, filter *nostr.Filter) {
+		if n := len(filter.Kinds); n > 0 {
+			newKinds := make([]int, 0, n)
+			for i := 0; i < n; i++ {
+				if k := filter.Kinds[i]; slices.Contains(kinds, uint16(k)) {
+					newKinds = append(newKinds, k)
+				}
+			}
+			filter.Kinds = newKinds
+		}
+	}
+}
+
+func RemoveAllButTags(tagNames ...string) func(context.Context, *nostr.Filter) {
+	return func(ctx context.Context, filter *nostr.Filter) {
+		for tagName := range filter.Tags {
+			if !slices.Contains(tagNames, tagName) {
+				delete(filter.Tags, tagName)
+			}
+		}
+	}
+}

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) {

relay.go

@@ -17,6 +17,12 @@ func NewRelay() *Relay {
 	return &Relay{
 		Log: log.New(os.Stderr, "[khatru-relay] ", log.LstdFlags),
 
+		Info: &nip11.RelayInformationDocument{
+			Software:      "https://github.com/fiatjaf/khatru",
+			Version:       "n/a",
+			SupportedNIPs: make([]int, 0),
+		},
+
 		upgrader: websocket.Upgrader{
 			ReadBufferSize:  1024,
 			WriteBufferSize: 1024,
@@ -34,25 +40,26 @@ func NewRelay() *Relay {
 }
 
 type Relay struct {
-	Name        string
+	ServiceURL string // required for nip-42
-	Description string
-	PubKey      string
-	Contact     string
-	ServiceURL  string // required for nip-42
-	IconURL     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)
-	StoreEvent               []func(ctx context.Context, event *nostr.Event) error
+	OverwriteResponseEvent    []func(ctx context.Context, event *nostr.Event)
-	DeleteEvent              []func(ctx context.Context, event *nostr.Event) error
+	OverwriteFilter           []func(ctx context.Context, filter *nostr.Filter)
-	QueryEvents              []func(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error)
+	OverwriteCountFilter      []func(ctx context.Context, filter *nostr.Filter)
-	CountEvents              []func(ctx context.Context, filter nostr.Filter) (int64, error)
+	OverwriteRelayInformation []func(ctx context.Context, r *http.Request, info nip11.RelayInformationDocument) nip11.RelayInformationDocument
-	EditInformation          []func(ctx context.Context, info *nip11.RelayInformationDocument)
+	StoreEvent                []func(ctx context.Context, event *nostr.Event) error
-	OnAuth                   []func(ctx context.Context, pubkey string)
+	DeleteEvent               []func(ctx context.Context, event *nostr.Event) error
-	OnConnect                []func(ctx context.Context)
+	QueryEvents               []func(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error)
-	OnEventSaved             []func(ctx context.Context, event *nostr.Event)
+	CountEvents               []func(ctx context.Context, filter nostr.Filter) (int64, error)
+	OnAuth                    []func(ctx context.Context, pubkey string)
+	OnConnect                 []func(ctx context.Context)
+	OnEventSaved              []func(ctx context.Context, event *nostr.Event)
+
+	// editing info will affect
+	Info *nip11.RelayInformationDocument
 
 	// Default logger, as set by NewServer, is a stdlib logger prefixed with "[khatru-relay] ",
 	// outputting to stderr.

serve-req.go

@@ -0,0 +1,82 @@
+package khatru
+
+import (
+	"context"
+	"sync"
+
+	"github.com/nbd-wtf/go-nostr"
+)
+
+func (rl *Relay) handleRequest(ctx context.Context, id string, eose *sync.WaitGroup, ws *WebSocket, filter nostr.Filter) {
+	defer eose.Done()
+
+	// overwrite the filter (for example, to eliminate some kinds or
+	// that we know we don't support)
+	for _, ovw := range rl.OverwriteFilter {
+		ovw(ctx, &filter)
+	}
+
+	if filter.Limit < 0 {
+		return
+	}
+
+	// then check if we'll reject this filter (we apply this after overwriting
+	// because we may, for example, remove some things from the incoming filters
+	// that we know we don't support, and then if the end result is an empty
+	// filter we can just reject it)
+	for _, reject := range rl.RejectFilter {
+		if reject, msg := reject(ctx, filter); reject {
+			ws.WriteJSON(nostr.NoticeEnvelope(msg))
+			return
+		}
+	}
+
+	// run the functions to query events (generally just one,
+	// but we might be fetching stuff from multiple places)
+	eose.Add(len(rl.QueryEvents))
+	for _, query := range rl.QueryEvents {
+		ch, err := query(ctx, filter)
+		if err != nil {
+			ws.WriteJSON(nostr.NoticeEnvelope(err.Error()))
+			eose.Done()
+			continue
+		}
+
+		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()
+		}(ch)
+	}
+}
+
+func (rl *Relay) handleCountRequest(ctx context.Context, ws *WebSocket, filter nostr.Filter) int64 {
+	// overwrite the filter (for example, to eliminate some kinds or tags that we know we don't support)
+	for _, ovw := range rl.OverwriteCountFilter {
+		ovw(ctx, &filter)
+	}
+
+	// then check if we'll reject this filter
+	for _, reject := range rl.RejectCountFilter {
+		if rejecting, msg := reject(ctx, filter); rejecting {
+			ws.WriteJSON(nostr.NoticeEnvelope(msg))
+			return 0
+		}
+	}
+
+	// run the functions to count (generally it will be just one)
+	var subtotal int64 = 0
+	for _, count := range rl.CountEvents {
+		res, err := count(ctx, filter)
+		if err != nil {
+			ws.WriteJSON(nostr.NoticeEnvelope(err.Error()))
+		}
+		subtotal += res
+	}
+
+	return subtotal
+}

start_test.go

@@ -1,93 +0,0 @@
-package khatru
-
-import (
-	"context"
-	"errors"
-	"net/http"
-	"testing"
-	"time"
-
-	"github.com/gobwas/ws/wsutil"
-	"github.com/nbd-wtf/go-nostr"
-)
-
-func TestServerStartShutdown(t *testing.T) {
-	var (
-		inited      bool
-		storeInited bool
-		shutdown    bool
-	)
-	rl := &testRelay{
-		name: "test server start",
-		init: func() error {
-			inited = true
-			return nil
-		},
-		onShutdown: func(context.Context) { shutdown = true },
-		storage: &testStorage{
-			init: func() error { storeInited = true; return nil },
-		},
-	}
-	srv, _ := NewServer(rl)
-	ready := make(chan bool)
-	done := make(chan error)
-	go func() { done <- srv.Start("127.0.0.1", 0, ready); close(done) }()
-	<-ready
-
-	// verify everything's initialized
-	if !inited {
-		t.Error("didn't call testRelay.init")
-	}
-	if !storeInited {
-		t.Error("didn't call testStorage.init")
-	}
-
-	// check that http requests are served
-	if _, err := http.Get("http://" + srv.Addr); err != nil {
-		t.Errorf("GET %s: %v", srv.Addr, err)
-	}
-
-	// verify server shuts down
-	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
-	defer cancel()
-	srv.Shutdown(ctx)
-	if !shutdown {
-		t.Error("didn't call testRelay.onShutdown")
-	}
-	select {
-	case err := <-done:
-		if err != nil {
-			t.Errorf("srv.Start: %v", err)
-		}
-	case <-time.After(time.Second):
-		t.Error("srv.Start too long to return")
-	}
-}
-
-func TestServerShutdownWebsocket(t *testing.T) {
-	// set up a new relay server
-	srv := startTestRelay(t, &testRelay{storage: &testStorage{}})
-
-	// connect a client to it
-	ctx1, cancel := context.WithTimeout(context.Background(), 2*time.Second)
-	defer cancel()
-	client, err := nostr.RelayConnect(ctx1, "ws://"+srv.Addr)
-	if err != nil {
-		t.Fatalf("nostr.RelayConnectContext: %v", err)
-	}
-
-	// now, shut down the server
-	ctx2, cancel := context.WithTimeout(context.Background(), 2*time.Second)
-	defer cancel()
-	srv.Shutdown(ctx2)
-
-	// wait for the client to receive a "connection close"
-	time.Sleep(1 * time.Second)
-	err = client.ConnectionError
-	if e := errors.Unwrap(err); e != nil {
-		err = e
-	}
-	if _, ok := err.(wsutil.ClosedError); !ok {
-		t.Errorf("client.ConnextionError: %v (%T); want wsutil.ClosedError", err, err)
-	}
-}

util_test.go

@@ -1,91 +0,0 @@
-package khatru
-
-import (
-	"context"
-	"testing"
-
-	"github.com/nbd-wtf/go-nostr"
-)
-
-func startTestRelay(t *testing.T, tr *testRelay) *Server {
-	t.Helper()
-	srv, _ := NewServer(tr)
-	started := make(chan bool)
-	go srv.Start("127.0.0.1", 0, started)
-	<-started
-	return srv
-}
-
-type testRelay struct {
-	name        string
-	storage     Storage
-	init        func() error
-	onShutdown  func(context.Context)
-	acceptEvent func(*nostr.Event) bool
-}
-
-func (tr *testRelay) Name() string                    { return tr.name }
-func (tr *testRelay) Storage(context.Context) Storage { return tr.storage }
-
-func (tr *testRelay) Init() error {
-	if fn := tr.init; fn != nil {
-		return fn()
-	}
-	return nil
-}
-
-func (tr *testRelay) OnShutdown(ctx context.Context) {
-	if fn := tr.onShutdown; fn != nil {
-		fn(ctx)
-	}
-}
-
-func (tr *testRelay) AcceptEvent(ctx context.Context, e *nostr.Event) bool {
-	if fn := tr.acceptEvent; fn != nil {
-		return fn(e)
-	}
-	return true
-}
-
-type testStorage struct {
-	init        func() error
-	queryEvents func(context.Context, *nostr.Filter) (chan *nostr.Event, error)
-	deleteEvent func(ctx context.Context, id string, pubkey string) error
-	saveEvent   func(context.Context, *nostr.Event) error
-	countEvents func(context.Context, *nostr.Filter) (int64, error)
-}
-
-func (st *testStorage) Init() error {
-	if fn := st.init; fn != nil {
-		return fn()
-	}
-	return nil
-}
-
-func (st *testStorage) QueryEvents(ctx context.Context, f *nostr.Filter) (chan *nostr.Event, error) {
-	if fn := st.queryEvents; fn != nil {
-		return fn(ctx, f)
-	}
-	return nil, nil
-}
-
-func (st *testStorage) DeleteEvent(ctx context.Context, id string, pubkey string) error {
-	if fn := st.deleteEvent; fn != nil {
-		return fn(ctx, id, pubkey)
-	}
-	return nil
-}
-
-func (st *testStorage) SaveEvent(ctx context.Context, e *nostr.Event) error {
-	if fn := st.saveEvent; fn != nil {
-		return fn(ctx, e)
-	}
-	return nil
-}
-
-func (st *testStorage) CountEvents(ctx context.Context, f *nostr.Filter) (int64, error) {
-	if fn := st.countEvents; fn != nil {
-		return fn(ctx, f)
-	}
-	return 0, nil
-}

utils.go

@@ -5,6 +5,8 @@ import (
 	"hash/maphash"
 	"regexp"
 	"unsafe"
+
+	"github.com/nbd-wtf/go-nostr"
 )
 
 const (
@@ -26,4 +28,11 @@ 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 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)
+}