bring in khatru and eventstore.

khatru/negentropy.go

@@ -0,0 +1,53 @@
+package khatru
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/fiatjaf/eventstore"
+	"github.com/nbd-wtf/go-nostr"
+	"github.com/nbd-wtf/go-nostr/nip77/negentropy"
+	"github.com/nbd-wtf/go-nostr/nip77/negentropy/storage/vector"
+)
+
+type NegentropySession struct {
+	neg           *negentropy.Negentropy
+	postponeClose func()
+}
+
+func (rl *Relay) startNegentropySession(ctx context.Context, filter nostr.Filter) (*vector.Vector, error) {
+	ctx = eventstore.SetNegentropy(ctx)
+
+	// do the same overwrite/reject flow we do in normal REQs
+	for _, ovw := range rl.OverwriteFilter {
+		ovw(ctx, &filter)
+	}
+	if filter.LimitZero {
+		return nil, fmt.Errorf("invalid limit 0")
+	}
+	for _, reject := range rl.RejectFilter {
+		if reject, msg := reject(ctx, filter); reject {
+			return nil, errors.New(nostr.NormalizeOKMessage(msg, "blocked"))
+		}
+	}
+
+	// fetch events and add them to a negentropy Vector store
+	vec := vector.New()
+	for _, query := range rl.QueryEvents {
+		ch, err := query(ctx, filter)
+		if err != nil {
+			continue
+		} else if ch == nil {
+			continue
+		}
+
+		for event := range ch {
+			// since the goal here is to sync databases we won't do fancy stuff like overwrite events
+			vec.Insert(event.CreatedAt, event.ID)
+		}
+	}
+	vec.Seal()
+
+	return vec, nil
+}