From ba38c28b99a1c7be91c4f11588d1b020275cb9b1 Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Wed, 15 Jan 2025 00:30:24 -0300
Subject: [PATCH] sdk: track event relays on kvstore.

---
 sdk/system.go  |  2 ++
 sdk/tracker.go | 29 +++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/sdk/system.go b/sdk/system.go
index 9f412fd..541b191 100644
--- a/sdk/system.go
+++ b/sdk/system.go
@@ -112,6 +112,8 @@ func NewSystem(mods ...SystemModifier) *System {
 	sys.Pool = nostr.NewSimplePool(context.Background(),
 		nostr.WithAuthorKindQueryMiddleware(sys.TrackQueryAttempts),
 		nostr.WithEventMiddleware(sys.TrackEventHints),
+		nostr.WithEventMiddleware(sys.TrackEventRelays),
+		nostr.WithDuplicateMiddleware(sys.TrackEventRelaysD),
 		nostr.WithPenaltyBox(),
 	)
 
diff --git a/sdk/tracker.go b/sdk/tracker.go
index 48da24e..eac395b 100644
--- a/sdk/tracker.go
+++ b/sdk/tracker.go
@@ -1,6 +1,7 @@
 package sdk
 
 import (
+	"encoding/hex"
 	"net/url"
 
 	"github.com/nbd-wtf/go-nostr"
@@ -108,3 +109,31 @@ func (sys *System) TrackEventHints(ie nostr.RelayEvent) {
 		}
 	}
 }
+
+func (sys *System) TrackEventRelays(ie nostr.RelayEvent) {
+	// decode the event ID hex into bytes
+	idBytes, err := hex.DecodeString(ie.ID)
+	if err != nil || len(idBytes) < 8 {
+		return
+	}
+
+	// store only first 8 bytes of event ID as key
+	key := idBytes[:8]
+
+	// store the relay URL as value
+	sys.KVStore.Set(key, []byte(ie.Relay.URL))
+}
+
+func (sys *System) TrackEventRelaysD(relay, id string) {
+	// decode the event ID hex into bytes
+	idBytes, err := hex.DecodeString(id)
+	if err != nil || len(idBytes) < 8 {
+		return
+	}
+
+	// store only first 8 bytes of event ID as key
+	key := idBytes[:8]
+
+	// store the relay URL as value
+	sys.KVStore.Set(key, []byte(relay))
+}