From c0c20b840123f4e6e71a5031c920f7a6cb296750 Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Sat, 8 Jul 2023 08:16:30 -0300
Subject: [PATCH] validate and normalize relay urls received from kind 3 and
 10002.

---
 sdk/relays.go | 10 ++++++++++
 utils.go      | 15 +++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/sdk/relays.go b/sdk/relays.go
index e8eb97f..79aea01 100644
--- a/sdk/relays.go
+++ b/sdk/relays.go
@@ -56,6 +56,11 @@ func ParseRelaysFromKind10002(evt *nostr.Event) []Relay {
 	result := make([]Relay, 0, len(evt.Tags))
 	for _, tag := range evt.Tags {
 		if u := tag.Value(); u != "" && tag[0] == "r" {
+			if !nostr.IsValidRelayURL(u) {
+				continue
+			}
+			u := nostr.NormalizeURL(u)
+
 			relay := Relay{
 				URL: u,
 			}
@@ -88,6 +93,11 @@ func ParseRelaysFromKind3(evt *nostr.Event) []Relay {
 	results := make([]Relay, len(items))
 	i := 0
 	for u, item := range items {
+		if !nostr.IsValidRelayURL(u) {
+			continue
+		}
+		u := nostr.NormalizeURL(u)
+
 		relay := Relay{
 			URL: u,
 		}
diff --git a/utils.go b/utils.go
index d06d6c6..44d36ea 100644
--- a/utils.go
+++ b/utils.go
@@ -1,6 +1,7 @@
 package nostr
 
 import (
+	"net/url"
 	"strings"
 
 	"golang.org/x/exp/constraints"
@@ -129,3 +130,17 @@ func InsertEventIntoDescendingList(sortedArray []*Event, event *Event) []*Event
 
 	return sortedArray
 }
+
+func IsValidRelayURL(u string) bool {
+	parsed, err := url.Parse(u)
+	if err != nil {
+		return false
+	}
+	if parsed.Scheme != "wss" && parsed.Scheme != "ws" {
+		return false
+	}
+	if len(strings.Split(parsed.Host, ".")) < 2 {
+		return false
+	}
+	return true
+}