validate and normalize relay urls received from kind 3 and 10002.

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,
 		}

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
+}