turn into a library.

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 fiatjaf
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.adoc

@@ -0,0 +1,67 @@
+= relay29 image:https://pkg.go.dev/badge/github.com/fiatjaf/relay29.svg[link=https://pkg.go.dev/github.com/fiatjaf/relay29]
+
+a library for creating NIP-29 relays, based on https://github.com/fiatjaf/khatru[khatru].
+
+CAUTION: This is probably broken so please don't trust it for anything serious and be prepared to delete your database.
+
+[source,go]
+---
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/fiatjaf/eventstore/slicestore"
+	"github.com/fiatjaf/khatru/policies"
+	"github.com/fiatjaf/relay29"
+	"github.com/nbd-wtf/go-nostr"
+	"golang.org/x/exp/slices"
+)
+
+func main() {
+	relayPrivateKey := nostr.GeneratePrivateKey()
+
+	state := relay29.Init(relay29.Options{
+		Domain:    "localhost:2929",
+		DB:        &slicestore.SliceStore{},
+		SecretKey: relayPrivateKey,
+	})
+
+	// init relay
+	state.Relay.Info.Name = "very ephemeral chat relay"
+	state.Relay.Info.PubKey, _ = nostr.GetPublicKey(relayPrivateKey)
+	state.Relay.Info.Description = "everything will be deleted as soon as I turn off my computer"
+
+	// extra policies
+	state.Relay.RejectEvent = slices.Insert(state.Relay.RejectEvent, 0,
+		policies.PreventLargeTags(64),
+		policies.PreventTooManyIndexableTags(6, []int{9005}, nil),
+		policies.RestrictToSpecifiedKinds(
+			9, 10, 11, 12,
+			30023, 31922, 31923, 9802,
+			9000, 9001, 9002, 9003, 9004, 9005, 9006, 9007,
+			9021,
+		),
+		policies.PreventTimestampsInThePast(60),
+		policies.PreventTimestampsInTheFuture(30),
+	)
+
+	// http routes
+	state.Relay.Router().HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprint(w, "nothing to see here, you must use a nip-29 powered client")
+	})
+
+	fmt.Println("running on http://0.0.0.0:2929")
+	if err := http.ListenAndServe(":2929", state.Relay); err != nil {
+		log.Fatal("failed to serve")
+	}
+}
+---
+
+== How to use
+
+Basically you just call `relay29.Init()` and then you get back a `relay29.State` object that has a normal `khatru.Relay` inside and and also a map of `Group` objects that you can read but you should not modify manually. To modify these groups you must write moderation events with the `.AddEvent()` method of the `Relay`. This API may be improved later.
+
+See link:examples/groups.fiatjaf.com/main.go[] for a (not very much) more complex example.

event_policy.go

@@ -1,73 +1,91 @@
-package main
+package relay29
 
 import (
 	"context"
 	"time"
 
-	"github.com/fiatjaf/set"
 	"github.com/nbd-wtf/go-nostr"
 	"github.com/nbd-wtf/go-nostr/nip29"
 	nip29_relay "github.com/nbd-wtf/go-nostr/nip29/relay"
+	"github.com/rs/zerolog/log"
 )
 
-const TOO_OLD = 60 // seconds
+const tooOld = 60 // seconds
 
-// events that just got deleted will be cached here for TOO_OLD seconds such that someone doesn't rebroadcast
+func (s *State) requireHTagForExistingGroup(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
-// them -- after that time we won't accept them anymore, so we can remove their ids from this cache
+	// this allows us to never check again in any of the other rules if the tag exists and just assume it exists always
-var deletedCache = set.NewSliceSet[string]()
-
-func requireHTagForExistingGroup(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
 	gtag := event.Tags.GetFirst([]string{"h", ""})
 	if gtag == nil {
 		return true, "missing group (`h`) tag"
 	}
 
-	if group := getGroupFromEvent(event); group == nil {
+	// skip this check when creating a group
+	if event.Kind == nostr.KindSimpleGroupCreateGroup {
+		return false, ""
+	}
+
+	// otherwise require a group to exist always
+	if group := s.GetGroupFromEvent(event); group == nil {
 		return true, "group '" + (*gtag)[1] + "' doesn't exist"
 	}
 
 	return false, ""
 }
 
-func restrictWritesBasedOnGroupRules(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+func (s *State) restrictWritesBasedOnGroupRules(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
-	// check it only for normal write events
+	group := s.GetGroupFromEvent(event)
-	if event.Kind == 9 || event.Kind == 11 {
-		group := getGroupFromEvent(event)
 
-		// only members can write
+	if event.Kind == nostr.KindSimpleGroupJoinRequest {
-		if _, isMember := group.Members[event.PubKey]; !isMember {
+		// anyone can apply to enter any group (if this is not desired a policy must be added to filter out this stuff)
-			return true, "unknown member"
+		group.mu.RLock()
+		defer group.mu.RUnlock()
+		if _, isMemberAlready := group.Members[event.PubKey]; isMemberAlready {
+			// unless you're already a member
+			return true, "already a member"
 		}
+		return false, ""
+	}
+
+	if event.Kind == nostr.KindSimpleGroupCreateGroup {
+		// anyone can create new groups (if this is not desired a policy must be added to filter out this stuff)
+		return false, ""
+	}
+
+	// only members can write
+	group.mu.RLock()
+	defer group.mu.RUnlock()
+	if _, isMember := group.Members[event.PubKey]; !isMember {
+		return true, "unknown member"
 	}
 
 	return false, ""
 }
 
-func preventWritingOfEventsJustDeleted(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+func (s *State) preventWritingOfEventsJustDeleted(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
-	if deletedCache.Has(event.ID) {
+	if s.deletedCache.Has(event.ID) {
 		return true, "this was deleted"
 	}
 	return false, ""
 }
 
-func restrictInvalidModerationActions(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+func (s *State) restrictInvalidModerationActions(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
 	if !nip29.MetadataEventKinds.Includes(event.Kind) {
 		return false, ""
 	}
 
 	// moderation action events must be new and not reused
-	if event.CreatedAt < nostr.Now()-TOO_OLD {
+	if event.CreatedAt < nostr.Now()-tooOld {
 		return true, "moderation action is too old (older than 1 minute ago)"
 	}
 
-	group := getGroupFromEvent(event)
+	group := s.GetGroupFromEvent(event)
 	if event.Kind == nostr.KindSimpleGroupCreateGroup && group != nil {
 		return true, "group already exists"
 	}
 
 	// will check if the moderation event author has sufficient permissions to perform this action
 	// except for the relay owner/pubkey, that has infinite permissions already
-	if event.PubKey == s.RelayPubkey {
+	if event.PubKey == s.publicKey {
 		return false, ""
 	}
 
@@ -76,6 +94,8 @@ func restrictInvalidModerationActions(ctx context.Context, event *nostr.Event) (
 		return true, "invalid moderation action: " + err.Error()
 	}
 
+	group.mu.RLock()
+	defer group.mu.RUnlock()
 	role, ok := group.Members[event.PubKey]
 	if !ok || role == nip29.EmptyRole {
 		return true, "unknown admin"
@@ -86,23 +106,24 @@ func restrictInvalidModerationActions(ctx context.Context, event *nostr.Event) (
 	return false, ""
 }
 
-func rateLimit(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+func (s *State) applyModerationAction(ctx context.Context, event *nostr.Event) {
-	group := getGroupFromEvent(event)
+	// turn event into a moderation action processor
-	if rsv := group.bucket.Reserve(); rsv.Delay() != 0 {
-		rsv.Cancel()
-		return true, "rate-limited"
-	} else {
-		rsv.OK()
-		return
-	}
-}
-
-func applyModerationAction(ctx context.Context, event *nostr.Event) {
 	action, err := nip29_relay.GetModerationAction(event)
 	if err != nil {
 		return
 	}
-	group := getGroupFromEvent(event)
+
+	// get group (or create it)
+	var group *Group
+	if event.Kind == nostr.KindSimpleGroupCreateGroup {
+		// if it's a group creation event we create the group first
+		groupId := GetGroupIDFromEvent(event)
+		group = s.NewGroup(groupId)
+		s.Groups.Store(groupId, group)
+	} else {
+		group = s.GetGroupFromEvent(event)
+	}
+	// apply the moderation action
 	action.Apply(&group.Group)
 
 	// if it's a delete event we have to actually delete stuff from the database here
@@ -114,19 +135,19 @@ func applyModerationAction(ctx context.Context, event *nostr.Event) {
 					log.Warn().Stringer("event", event).Msg("delete request came with a broken \"e\" tag")
 					continue
 				}
-				res, err := db.QueryEvents(ctx, nostr.Filter{IDs: []string{id}})
+				res, err := s.DB.QueryEvents(ctx, nostr.Filter{IDs: []string{id}})
 				if err != nil {
 					log.Warn().Err(err).Msg("failed to query event to be deleted")
 					continue
 				}
 				for target := range res {
-					if err := db.DeleteEvent(ctx, target); err != nil {
+					if err := s.DB.DeleteEvent(ctx, target); err != nil {
 						log.Warn().Err(err).Stringer("event", target).Msg("failed to delete")
 					} else {
-						deletedCache.Add(target.ID)
+						s.deletedCache.Add(target.ID)
 						go func(id string) {
-							time.Sleep(TOO_OLD * time.Second)
+							time.Sleep(tooOld * time.Second)
-							deletedCache.Remove(id)
+							s.deletedCache.Remove(id)
 						}(target.ID)
 					}
 				}
@@ -134,29 +155,29 @@ func applyModerationAction(ctx context.Context, event *nostr.Event) {
 		}
 	}
 
-	// propagate new replaceable events to listeners
+	// propagate new replaceable events to listeners depending on what changed happened
 	switch event.Kind {
-	case nostr.KindSimpleGroupEditMetadata, nostr.KindSimpleGroupEditGroupStatus:
+	case nostr.KindSimpleGroupCreateGroup, nostr.KindSimpleGroupEditMetadata, nostr.KindSimpleGroupEditGroupStatus:
 		evt := group.ToMetadataEvent()
-		evt.Sign(s.RelayPrivkey)
+		evt.Sign(s.privateKey)
-		relay.BroadcastEvent(evt)
+		s.Relay.BroadcastEvent(evt)
 	case nostr.KindSimpleGroupAddPermission, nostr.KindSimpleGroupRemovePermission:
 		evt := group.ToMetadataEvent()
-		evt.Sign(s.RelayPrivkey)
+		evt.Sign(s.privateKey)
-		relay.BroadcastEvent(evt)
+		s.Relay.BroadcastEvent(evt)
 	case nostr.KindSimpleGroupAddUser, nostr.KindSimpleGroupRemoveUser:
 		evt := group.ToMembersEvent()
-		evt.Sign(s.RelayPrivkey)
+		evt.Sign(s.privateKey)
-		relay.BroadcastEvent(evt)
+		s.Relay.BroadcastEvent(evt)
 	}
 }
 
-func reactToJoinRequest(ctx context.Context, event *nostr.Event) {
+func (s *State) reactToJoinRequest(ctx context.Context, event *nostr.Event) {
-	if event.Kind != 9021 {
+	if event.Kind != nostr.KindSimpleGroupJoinRequest {
 		return
 	}
 
-	group := getGroupFromEvent(event)
+	group := s.GetGroupFromEvent(event)
 	if !group.Closed {
 		// immediately add the requester
 		addUser := &nostr.Event{
@@ -167,22 +188,14 @@ func reactToJoinRequest(ctx context.Context, event *nostr.Event) {
 				nostr.Tag{"p", event.PubKey},
 			},
 		}
-		if err := addUser.Sign(s.RelayPrivkey); err != nil {
+		if err := addUser.Sign(s.privateKey); err != nil {
 			log.Error().Err(err).Msg("failed to sign add-user event")
 			return
 		}
-		if _, err := relay.AddEvent(ctx, addUser); err != nil {
+		if _, err := s.Relay.AddEvent(ctx, addUser); err != nil {
 			log.Error().Err(err).Msg("failed to add user who requested to join")
 			return
 		}
-		relay.BroadcastEvent(addUser)
+		s.Relay.BroadcastEvent(addUser)
 	}
 }
-
-func blockDeletesOfOldMessages(ctx context.Context, target, deletion *nostr.Event) (acceptDeletion bool, msg string) {
-	if target.CreatedAt < nostr.Now()-60*60*2 /* 2 hours */ {
-		return false, "can't delete old event, contact relay admin"
-	}
-
-	return true, ""
-}

examples/basic/main.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/fiatjaf/eventstore/slicestore"
+	"github.com/fiatjaf/khatru/policies"
+	"github.com/fiatjaf/relay29"
+	"github.com/nbd-wtf/go-nostr"
+	"golang.org/x/exp/slices"
+)
+
+func main() {
+	relayPrivateKey := nostr.GeneratePrivateKey()
+
+	state := relay29.Init(relay29.Options{
+		Domain:    "localhost:2929",
+		DB:        &slicestore.SliceStore{},
+		SecretKey: relayPrivateKey,
+	})
+
+	// init relay
+	state.Relay.Info.Name = "very ephemeral chat relay"
+	state.Relay.Info.PubKey, _ = nostr.GetPublicKey(relayPrivateKey)
+	state.Relay.Info.Description = "everything will be deleted as soon as I turn off my computer"
+
+	// extra policies
+	state.Relay.RejectEvent = slices.Insert(state.Relay.RejectEvent, 0,
+		policies.PreventLargeTags(64),
+		policies.PreventTooManyIndexableTags(6, []int{9005}, nil),
+		policies.RestrictToSpecifiedKinds(
+			9, 10, 11, 12,
+			30023, 31922, 31923, 9802,
+			9000, 9001, 9002, 9003, 9004, 9005, 9006, 9007,
+			9021,
+		),
+		policies.PreventTimestampsInThePast(60),
+		policies.PreventTimestampsInTheFuture(30),
+	)
+
+	// http routes
+	state.Relay.Router().HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprint(w, "nothing to see here, you must use a nip-29 powered client")
+	})
+
+	fmt.Println("running on http://0.0.0.0:2929")
+	if err := http.ListenAndServe(":2929", state.Relay); err != nil {
+		log.Fatal("failed to serve")
+	}
+}

examples/groups.fiatjaf.com/extra_policies.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"context"
+	"time"
+
+	"github.com/fiatjaf/relay29"
+	"github.com/nbd-wtf/go-nostr"
+	"github.com/puzpuzpuz/xsync/v3"
+	"golang.org/x/time/rate"
+)
+
+var internalCallContextKey = struct{}{}
+
+func preventGroupCreation(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+	if event.Kind == 9007 && ctx.Value(internalCallContextKey) == nil {
+		return true, "to create groups open https://" + s.Domain + " in your web browser"
+	}
+	return false, ""
+}
+
+func blockDeletesOfOldMessages(ctx context.Context, target, deletion *nostr.Event) (acceptDeletion bool, msg string) {
+	if target.CreatedAt < nostr.Now()-60*60*2 /* 2 hours */ {
+		return false, "can't delete old event, contact relay admin"
+	}
+
+	return true, ""
+}
+
+// very strict rate limits
+var rateLimitBuckets = xsync.NewMapOf[*relay29.Group, *rate.Limiter]()
+
+func rateLimit(ctx context.Context, event *nostr.Event) (reject bool, msg string) {
+	group := state.GetGroupFromEvent(event)
+
+	bucket, _ := rateLimitBuckets.LoadOrCompute(group, func() *rate.Limiter {
+		return rate.NewLimiter(rate.Every(time.Minute*2), 15)
+	})
+
+	if rsv := bucket.Reserve(); rsv.Delay() != 0 {
+		rsv.Cancel()
+		return true, "rate-limited"
+	} else {
+		rsv.OK()
+		return
+	}
+}

examples/groups.fiatjaf.com/handlers.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"encoding/binary"
 	"encoding/hex"
 	"fmt"
@@ -39,15 +40,15 @@ func handleCreateGroup(w http.ResponseWriter, r *http.Request) {
 
 	log.Info().Str("id", groupId).Str("owner", pubkey).Msg("making group")
 
-	group, _ := groups.Load(groupId)
+	group, _ := state.Groups.Load(groupId)
 	if group != nil {
 		http.Error(w, "group already exists", 403)
 		return
 	}
 
 	// create group right here
-	group = newGroup(groupId)
+	group = state.NewGroup(groupId)
-	groups.Store(groupId, group)
+	state.Groups.Store(groupId, group)
 
 	foundingEvents := []*nostr.Event{
 		{
@@ -81,13 +82,16 @@ func handleCreateGroup(w http.ResponseWriter, r *http.Request) {
 			},
 		},
 	}
+
+	ourCtx := context.WithValue(r.Context(), internalCallContextKey, &struct{}{})
+
 	for _, evt := range foundingEvents {
 		if err := evt.Sign(s.RelayPrivkey); err != nil {
 			log.Error().Err(err).Msg("error signing group creation event")
 			http.Error(w, "error signing group creation event: "+err.Error(), 500)
 			return
 		}
-		if _, err := relay.AddEvent(r.Context(), evt); err != nil {
+		if _, err := state.Relay.AddEvent(ourCtx, evt); err != nil {
 			log.Error().Err(err).Stringer("event", evt).Msg("failed to save group creation event")
 			http.Error(w, "failed to save group creation event", 501)
 			return

examples/groups.fiatjaf.com/main.go

@@ -1,13 +1,13 @@
 package main
 
 import (
-	"context"
 	"net/http"
 	"os"
+	"slices"
 
 	"github.com/fiatjaf/eventstore/bolt"
-	"github.com/fiatjaf/khatru"
 	"github.com/fiatjaf/khatru/policies"
+	"github.com/fiatjaf/relay29"
 	"github.com/kelseyhightower/envconfig"
 	"github.com/nbd-wtf/go-nostr"
 	"github.com/rs/zerolog"
@@ -30,7 +30,7 @@ var (
 	s     Settings
 	db    = &bolt.BoltBackend{}
 	log   = zerolog.New(os.Stderr).Output(zerolog.ConsoleWriter{Out: os.Stdout}).With().Timestamp().Logger()
-	relay = khatru.NewRelay()
+	state *relay29.State
 )
 
 func main() {
@@ -49,61 +49,44 @@ func main() {
 	}
 	log.Debug().Str("path", db.Path).Msg("initialized database")
 
-	// load all groups
+	// init relay29 stuff
-	loadGroups(context.Background())
+	state = relay29.Init(relay29.Options{
+		Domain:    s.Domain,
+		DB:        db,
+		SecretKey: s.RelayPrivkey,
+	})
 
 	// init relay
-	relay.Info.Name = s.RelayName
+	state.Relay.Info.Name = s.RelayName
-	relay.Info.PubKey = s.RelayPubkey
+	state.Relay.Info.PubKey = s.RelayPubkey
-	relay.Info.Description = s.RelayDescription
+	state.Relay.Info.Description = s.RelayDescription
-	relay.Info.Contact = s.RelayContact
+	state.Relay.Info.Contact = s.RelayContact
-	relay.Info.Icon = s.RelayIcon
+	state.Relay.Info.Icon = s.RelayIcon
-	relay.Info.SupportedNIPs = append(relay.Info.SupportedNIPs, 29)
 
-	relay.StoreEvent = append(relay.StoreEvent, db.SaveEvent)
+	state.Relay.OverwriteDeletionOutcome = append(state.Relay.OverwriteDeletionOutcome,
-	relay.QueryEvents = append(relay.QueryEvents,
-		normalEventQuery,
-		metadataQueryHandler,
-		adminsQueryHandler,
-		membersQueryHandler,
-	)
-	relay.CountEvents = append(relay.CountEvents, db.CountEvents)
-	relay.DeleteEvent = append(relay.DeleteEvent, db.DeleteEvent)
-	relay.OverwriteDeletionOutcome = append(relay.OverwriteDeletionOutcome,
 		blockDeletesOfOldMessages,
 	)
-	relay.RejectFilter = append(relay.RejectFilter,
+	state.Relay.RejectEvent = slices.Insert(state.Relay.RejectEvent, 0,
-		requireKindAndSingleGroupIDOrSpecificEventReference,
-	)
-	relay.RejectEvent = append(relay.RejectEvent,
-		requireHTagForExistingGroup,
 		policies.PreventLargeTags(64),
 		policies.PreventTooManyIndexableTags(6, []int{9005}, nil),
 		policies.RestrictToSpecifiedKinds(
-			9, 11, 12,
+			9, 10, 11, 12,
 			30023, 31922, 31923, 9802,
 			9000, 9001, 9002, 9003, 9004, 9005, 9006, 9007,
 			9021,
 		),
 		policies.PreventTimestampsInThePast(60),
 		policies.PreventTimestampsInTheFuture(30),
-		restrictWritesBasedOnGroupRules,
-		restrictInvalidModerationActions,
 		rateLimit,
-		preventWritingOfEventsJustDeleted,
+		preventGroupCreation,
 	)
-	relay.OnEventSaved = append(relay.OnEventSaved,
-		applyModerationAction,
-		reactToJoinRequest,
-	)
-	relay.OnConnect = append(relay.OnConnect, khatru.RequestAuth)
 
 	// http routes
-	relay.Router().HandleFunc("/create", handleCreateGroup)
+	state.Relay.Router().HandleFunc("/create", handleCreateGroup)
-	relay.Router().HandleFunc("/", handleHomepage)
+	state.Relay.Router().HandleFunc("/", handleHomepage)
 
 	log.Info().Str("relay-pubkey", s.RelayPubkey).Msg("running on http://0.0.0.0:" + s.Port)
-	if err := http.ListenAndServe(":"+s.Port, relay); err != nil {
+	if err := http.ListenAndServe(":"+s.Port, state.Relay); err != nil {
 		log.Fatal().Err(err).Msg("failed to serve")
 	}
 }

filter_policy.go

@@ -1,4 +1,4 @@
-package main
+package relay29
 
 import (
 	"context"
@@ -9,7 +9,7 @@ import (
 	"github.com/nbd-wtf/go-nostr/nip29"
 )
 
-func requireKindAndSingleGroupIDOrSpecificEventReference(ctx context.Context, filter nostr.Filter) (reject bool, msg string) {
+func (s *State) requireKindAndSingleGroupIDOrSpecificEventReference(ctx context.Context, filter nostr.Filter) (reject bool, msg string) {
 	isMeta := false
 	isNormal := false
 	isReference := false
@@ -44,7 +44,7 @@ func requireKindAndSingleGroupIDOrSpecificEventReference(ctx context.Context, fi
 		if tags, ok := filter.Tags["h"]; ok && len(tags) > 0 {
 			// "h" tags specified
 			for _, tag := range tags {
-				if group, _ := groups.Load(tag); group != nil {
+				if group, _ := s.Groups.Load(tag); group != nil {
 					if !group.Private {
 						continue // fine, this is public
 					}

groups.go

@@ -1,75 +0,0 @@
-package main
-
-import (
-	"context"
-	"strings"
-	"sync"
-	"time"
-
-	"github.com/nbd-wtf/go-nostr"
-	"github.com/nbd-wtf/go-nostr/nip29"
-	nip29_relay "github.com/nbd-wtf/go-nostr/nip29/relay"
-	"github.com/puzpuzpuz/xsync/v3"
-	"golang.org/x/time/rate"
-)
-
-type Group struct {
-	nip29.Group
-	bucket *rate.Limiter
-	mu     sync.RWMutex
-}
-
-var groups = xsync.NewMapOf[string, *Group]()
-
-func newGroup(id string) *Group {
-	return &Group{
-		Group: nip29.Group{
-			Address: nip29.GroupAddress{
-				ID:    id,
-				Relay: "wss://" + s.Domain,
-			},
-			Members: map[string]*nip29.Role{},
-		},
-
-		// very strict rate limits
-		bucket: rate.NewLimiter(rate.Every(time.Minute*2), 15),
-	}
-}
-
-// loadGroups loads all the group metadata from all the past action messages
-func loadGroups(ctx context.Context) {
-	groupMetadataEvents, _ := db.QueryEvents(ctx, nostr.Filter{Limit: db.MaxLimit, Kinds: []int{nostr.KindSimpleGroupCreateGroup}})
-	for evt := range groupMetadataEvents {
-		gtag := evt.Tags.GetFirst([]string{"h", ""})
-		id := (*gtag)[1]
-
-		group := newGroup(id)
-		f := nostr.Filter{
-			Limit: 5000, Kinds: nip29.ModerationEventKinds, Tags: nostr.TagMap{"h": []string{id}},
-		}
-		ch, _ := db.QueryEvents(ctx, f)
-
-		events := make([]*nostr.Event, 0, 5000)
-		for event := range ch {
-			events = append(events, event)
-		}
-		for i := len(events) - 1; i >= 0; i-- {
-			evt := events[i]
-			act, _ := nip29_relay.GetModerationAction(evt)
-			act.Apply(&group.Group)
-		}
-
-		groups.Store(group.Address.ID, group)
-	}
-}
-
-func getGroupFromEvent(event *nostr.Event) *Group {
-	gtag := event.Tags.GetFirst([]string{"h", ""})
-	groupId := (*gtag)[1]
-	group, _ := groups.Load(groupId)
-	return group
-}
-
-func groupComparator(g *Group, id string) int {
-	return strings.Compare(g.Address.ID, id)
-}

queries.go

@@ -1,4 +1,4 @@
-package main
+package relay29
 
 import (
 	"context"
@@ -9,14 +9,14 @@ import (
 	"golang.org/x/exp/slices"
 )
 
-func metadataQueryHandler(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
+func (s *State) metadataQueryHandler(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
 	ch := make(chan *nostr.Event, 1)
 
 	go func() {
 		if slices.Contains(filter.Kinds, nostr.KindSimpleGroupMetadata) {
 			if _, ok := filter.Tags["d"]; !ok {
 				// no "d" tag specified, return everything
-				groups.Range(func(_ string, group *Group) bool {
+				s.Groups.Range(func(_ string, group *Group) bool {
 					if group.Private {
 						// don't reveal metadata about private groups in lists
 						return true
@@ -25,15 +25,15 @@ func metadataQueryHandler(ctx context.Context, filter nostr.Filter) (chan *nostr
 					}
 
 					evt := group.ToMetadataEvent()
-					evt.Sign(s.RelayPrivkey)
+					evt.Sign(s.privateKey)
 					ch <- evt
 					return true
 				})
 			} else {
 				for _, groupId := range filter.Tags["d"] {
-					if group, _ := groups.Load(groupId); group != nil {
+					if group, _ := s.Groups.Load(groupId); group != nil {
 						evt := group.ToMetadataEvent()
-						evt.Sign(s.RelayPrivkey)
+						evt.Sign(s.privateKey)
 						ch <- evt
 					}
 				}
@@ -46,33 +46,33 @@ func metadataQueryHandler(ctx context.Context, filter nostr.Filter) (chan *nostr
 	return ch, nil
 }
 
-func adminsQueryHandler(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
+func (s *State) adminsQueryHandler(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
 	ch := make(chan *nostr.Event, 1)
 
 	go func() {
 		if slices.Contains(filter.Kinds, nostr.KindSimpleGroupAdmins) {
 			if _, ok := filter.Tags["d"]; !ok {
 				// no "d" tag specified, return everything
-				groups.Range(func(_ string, group *Group) bool {
+				s.Groups.Range(func(_ string, group *Group) bool {
 					if group.Private {
 						// don't reveal lists of admins of private groups ever
 						return true
 					}
 
 					evt := group.ToAdminsEvent()
-					evt.Sign(s.RelayPrivkey)
+					evt.Sign(s.privateKey)
 					ch <- evt
 					return true
 				})
 			} else {
 				for _, groupId := range filter.Tags["d"] {
-					if group, _ := groups.Load(groupId); group != nil {
+					if group, _ := s.Groups.Load(groupId); group != nil {
 						if group.Private {
 							// don't reveal lists of admins of private groups ever
 							continue
 						}
 						evt := group.ToAdminsEvent()
-						evt.Sign(s.RelayPrivkey)
+						evt.Sign(s.privateKey)
 						ch <- evt
 					}
 				}
@@ -85,32 +85,32 @@ func adminsQueryHandler(ctx context.Context, filter nostr.Filter) (chan *nostr.E
 	return ch, nil
 }
 
-func membersQueryHandler(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
+func (s *State) membersQueryHandler(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
 	ch := make(chan *nostr.Event, 1)
 
 	go func() {
 		if slices.Contains(filter.Kinds, nostr.KindSimpleGroupMembers) {
 			if _, ok := filter.Tags["d"]; !ok {
 				// no "d" tag specified, return everything
-				groups.Range(func(_ string, group *Group) bool {
+				s.Groups.Range(func(_ string, group *Group) bool {
 					if group.Private {
 						// don't reveal lists of members of private groups ever
 						return true
 					}
 					evt := group.ToMembersEvent()
-					evt.Sign(s.RelayPrivkey)
+					evt.Sign(s.privateKey)
 					ch <- evt
 					return true
 				})
 			} else {
 				for _, groupId := range filter.Tags["d"] {
-					if group, _ := groups.Load(groupId); group != nil {
+					if group, _ := s.Groups.Load(groupId); group != nil {
 						if group.Private {
 							// don't reveal lists of members of private groups ever
 							continue
 						}
 						evt := group.ToMembersEvent()
-						evt.Sign(s.RelayPrivkey)
+						evt.Sign(s.privateKey)
 						ch <- evt
 					}
 				}
@@ -123,10 +123,10 @@ func membersQueryHandler(ctx context.Context, filter nostr.Filter) (chan *nostr.
 	return ch, nil
 }
 
-func normalEventQuery(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
+func (s *State) normalEventQuery(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
 	if hTags, hasHTags := filter.Tags["h"]; hasHTags && len(hTags) > 0 {
 		// if these tags are present we already know access is safe because we've verified that in filter_policy.go
-		return db.QueryEvents(ctx, filter)
+		return s.DB.QueryEvents(ctx, filter)
 	}
 
 	ch := make(chan *nostr.Event)
@@ -136,11 +136,11 @@ func normalEventQuery(ctx context.Context, filter nostr.Filter) (chan *nostr.Eve
 		var results chan *nostr.Event
 		var err error
 		if refE, ok := filter.Tags["e"]; ok && len(refE) > 0 {
-			results, err = db.QueryEvents(ctx, filter)
+			results, err = s.DB.QueryEvents(ctx, filter)
 		} else if refA, ok := filter.Tags["a"]; ok && len(refA) > 0 {
-			results, err = db.QueryEvents(ctx, filter)
+			results, err = s.DB.QueryEvents(ctx, filter)
 		} else if len(filter.IDs) > 0 {
-			results, err = db.QueryEvents(ctx, filter)
+			results, err = s.DB.QueryEvents(ctx, filter)
 		} else {
 			// we must end here for all the metadata queries and so on otherwise they will never close
 			close(ch)
@@ -152,7 +152,7 @@ func normalEventQuery(ctx context.Context, filter nostr.Filter) (chan *nostr.Eve
 		allowed := set.NewSliceSet[string]()
 		disallowed := set.NewSliceSet[string]()
 		for evt := range results {
-			if group := getGroupFromEvent(evt); !group.Private || allowed.Has(group.Address.ID) {
+			if group := s.GetGroupFromEvent(evt); !group.Private || allowed.Has(group.Address.ID) {
 				ch <- evt
 			} else if authed != "" && !disallowed.Has(group.Address.ID) {
 				group.mu.RLock()

state.go

@@ -0,0 +1,140 @@
+package relay29
+
+import (
+	"context"
+	"sync"
+
+	"github.com/fiatjaf/eventstore"
+	"github.com/fiatjaf/khatru"
+	"github.com/fiatjaf/set"
+	"github.com/nbd-wtf/go-nostr"
+	"github.com/nbd-wtf/go-nostr/nip29"
+	nip29_relay "github.com/nbd-wtf/go-nostr/nip29/relay"
+	"github.com/puzpuzpuz/xsync/v3"
+)
+
+type State struct {
+	Relay  *khatru.Relay
+	Domain string
+	Groups *xsync.MapOf[string, *Group]
+	DB     eventstore.Store
+
+	deletedCache set.Set[string]
+	publicKey    string
+	privateKey   string
+}
+
+type Options struct {
+	Domain    string
+	DB        eventstore.Store
+	SecretKey string
+}
+
+func Init(opts Options) *State {
+	pubkey, _ := nostr.GetPublicKey(opts.SecretKey)
+
+	// events that just got deleted will be cached here for `tooOld` seconds such that someone doesn't rebroadcast
+	// them -- after that time we won't accept them anymore, so we can remove their ids from this cache
+	deletedCache := set.NewSliceSet[string]()
+
+	// we keep basic data about all groups in memory
+	groups := xsync.NewMapOf[string, *Group]()
+
+	// we create a new khatru relay
+	relay := khatru.NewRelay()
+	relay.Info.SupportedNIPs = append(relay.Info.SupportedNIPs, 29)
+
+	state := &State{
+		relay,
+		opts.Domain,
+		groups,
+		opts.DB,
+		deletedCache,
+		pubkey,
+		opts.SecretKey,
+	}
+
+	// load all groups
+	state.loadGroups(context.Background())
+
+	// apply basic relay policies
+	relay.StoreEvent = append(relay.StoreEvent, state.DB.SaveEvent)
+	relay.QueryEvents = append(relay.QueryEvents,
+		state.normalEventQuery,
+		state.metadataQueryHandler,
+		state.adminsQueryHandler,
+		state.membersQueryHandler,
+	)
+	relay.DeleteEvent = append(relay.DeleteEvent, state.DB.DeleteEvent)
+	relay.RejectFilter = append(relay.RejectFilter,
+		state.requireKindAndSingleGroupIDOrSpecificEventReference,
+	)
+	relay.RejectEvent = append(relay.RejectEvent,
+		state.requireHTagForExistingGroup,
+		state.restrictWritesBasedOnGroupRules,
+		state.restrictInvalidModerationActions,
+		state.preventWritingOfEventsJustDeleted,
+	)
+	relay.OnEventSaved = append(relay.OnEventSaved,
+		state.applyModerationAction,
+		state.reactToJoinRequest,
+	)
+	relay.OnConnect = append(relay.OnConnect, khatru.RequestAuth)
+
+	return state
+}
+
+type Group struct {
+	nip29.Group
+	mu sync.RWMutex
+}
+
+func (s *State) NewGroup(id string) *Group {
+	return &Group{
+		Group: nip29.Group{
+			Address: nip29.GroupAddress{
+				ID:    id,
+				Relay: "wss://" + s.Domain,
+			},
+			Members: map[string]*nip29.Role{},
+		},
+	}
+}
+
+// loadGroups loads all the group metadata from all the past action messages.
+func (s *State) loadGroups(ctx context.Context) {
+	groupMetadataEvents, _ := s.DB.QueryEvents(ctx, nostr.Filter{Kinds: []int{nostr.KindSimpleGroupCreateGroup}})
+	for evt := range groupMetadataEvents {
+		gtag := evt.Tags.GetFirst([]string{"h", ""})
+		id := (*gtag)[1]
+
+		group := s.NewGroup(id)
+		f := nostr.Filter{
+			Limit: 5000, Kinds: nip29.ModerationEventKinds, Tags: nostr.TagMap{"h": []string{id}},
+		}
+		ch, _ := s.DB.QueryEvents(ctx, f)
+
+		events := make([]*nostr.Event, 0, 5000)
+		for event := range ch {
+			events = append(events, event)
+		}
+		for i := len(events) - 1; i >= 0; i-- {
+			evt := events[i]
+			act, _ := nip29_relay.GetModerationAction(evt)
+			act.Apply(&group.Group)
+		}
+
+		s.Groups.Store(group.Address.ID, group)
+	}
+}
+
+func (s *State) GetGroupFromEvent(event *nostr.Event) *Group {
+	group, _ := s.Groups.Load(GetGroupIDFromEvent(event))
+	return group
+}
+
+func GetGroupIDFromEvent(event *nostr.Event) string {
+	gtag := event.Tags.GetFirst([]string{"h", ""})
+	groupId := (*gtag)[1]
+	return groupId
+}