OverwriteResponseEvent for optionally modifying events before sending them to client.

README.md

@@ -1,116 +1 @@
-# khatru, a relay framework [![docs badge](https://img.shields.io/badge/docs-reference-blue)](https://pkg.go.dev/github.com/fiatjaf/khatru#Relay)
-
-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.Name = "my relay"
-	relay.PubKey = "79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798"
-	relay.Description = "this is my custom relay"
-	relay.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"
-
-	// 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)
-```
+khatru

add-event.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 
-	"github.com/fiatjaf/eventstore"
 	"github.com/nbd-wtf/go-nostr"
 )
 
@@ -39,7 +38,8 @@ func (rl *Relay) AddEvent(ctx context.Context, evt *nostr.Event) error {
 				if err != nil {
 					continue
 				}
-				if previous := <-ch; previous != nil && isOlder(previous, evt) {
+				previous := <-ch
+				if previous != nil {
 					for _, del := range rl.DeleteEvent {
 						del(ctx, previous)
 					}
@@ -54,7 +54,8 @@ func (rl *Relay) AddEvent(ctx context.Context, evt *nostr.Event) error {
 					if err != nil {
 						continue
 					}
-					if previous := <-ch; previous != nil && isOlder(previous, evt) {
+					previous := <-ch
+					if previous != nil {
 						for _, del := range rl.DeleteEvent {
 							del(ctx, previous)
 						}
@@ -67,7 +68,7 @@ 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 eventstore.ErrDupEvent:
+				case ErrDupEvent:
 					return nil
 				default:
 					errmsg := saveErr.Error()

errors.go

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

examples/readme-demo/main.go

@@ -1,87 +0,0 @@
-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.Name = "my relay"
-	relay.PubKey = "79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798"
-	relay.Description = "this is my custom relay"
-	relay.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"
-
-	// 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)
-}

handlers.go

@@ -124,10 +124,12 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 
 					// check signature (requires the ID to be set)
 					if ok, err := evt.CheckSignature(); err != nil {
-						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "error: failed to verify signature"})
+						reason := "error: failed to verify signature"
+						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: &reason})
 						return
 					} else if !ok {
-						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "invalid: signature is invalid"})
+						reason := "invalid: signature is invalid"
+						ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: &reason})
 						return
 					}
 
@@ -137,12 +139,12 @@ 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 {
-						reason = err.Error()
+						msg := err.Error()
+						reason = &msg
 					}
 					ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: ok, Reason: reason})
 				case "COUNT":
@@ -168,12 +170,12 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 
 						filter := filters[i]
 
-						// 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)
+						for _, reject := range rl.RejectFilter {
+							if rejecting, msg := reject(ctx, filter); rejecting {
+								ws.WriteJSON(nostr.NoticeEnvelope(msg))
+								continue
+							}
 						}
-
-						// 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))
@@ -181,7 +183,6 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 							}
 						}
 
-						// run the functions to count (generally it will be just one)
 						for _, count := range rl.CountEvents {
 							res, err := count(ctx, filter)
 							if err != nil {
@@ -216,25 +217,14 @@ func (rl *Relay) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 
 						filter := filters[i]
 
-						// 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)
-						}
-
-						// 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 {
+						for _, reject := range rl.RejectCountFilter {
 							if rejecting, msg := reject(ctx, filter); rejecting {
 								ws.WriteJSON(nostr.NoticeEnvelope(msg))
+								eose.Done()
 								continue
 							}
 						}
 
-						// 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)
@@ -286,7 +276,8 @@ 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 {
-							ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: "error: failed to authenticate"})
+							reason := "error: failed to authenticate"
+							ws.WriteJSON(nostr.OKEnvelope{EventID: evt.ID, OK: false, Reason: &reason})
 						}
 					}
 				}

plugins/events.go

@@ -56,21 +56,3 @@ func RestrictToSpecifiedKinds(kinds ...uint16) func(context.Context, *nostr.Even
 		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, ""
-	}
-}

plugins/filters.go

@@ -2,11 +2,26 @@ package plugins
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/nbd-wtf/go-nostr"
-	"golang.org/x/exp/slices"
 )
 
+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)
 
@@ -16,49 +31,3 @@ func NoComplexFilters(ctx context.Context, filter nostr.Filter) (reject bool, ms
 
 	return false, ""
 }
-
-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, ""
-}
-
-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)
-			}
-		}
-	}
-}

relay.go

@@ -46,8 +46,6 @@ type Relay struct {
 	RejectCountFilter        []func(ctx context.Context, filter nostr.Filter) (reject bool, msg string)
 	OverwriteDeletionOutcome []func(ctx context.Context, target *nostr.Event, deletion *nostr.Event) (acceptDeletion bool, msg string)
 	OverwriteResponseEvent   []func(ctx context.Context, event *nostr.Event)
-	OverwriteFilter          []func(ctx context.Context, filter *nostr.Filter)
-	OverwriteCountFilter     []func(ctx context.Context, filter *nostr.Filter)
 	StoreEvent               []func(ctx context.Context, event *nostr.Event) error
 	DeleteEvent              []func(ctx context.Context, event *nostr.Event) error
 	QueryEvents              []func(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error)

utils.go

@@ -5,8 +5,6 @@ import (
 	"hash/maphash"
 	"regexp"
 	"unsafe"
-
-	"github.com/nbd-wtf/go-nostr"
 )
 
 const (
@@ -28,11 +26,4 @@ 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)
-}
+func pointerHasher[V any](_ maphash.Seed, k *V) uint64 { return uint64(uintptr(unsafe.Pointer(k))) }