Improve localhost address validation (#9634)

* 🎨 Improv localhost address validation

* 🐛 Compatible with browser extension

kernel/util/net.go

@@ -17,6 +17,7 @@
 package util
 
 import (
+	"net"
 	"net/http"
 	"net/url"
 	"strings"
@@ -31,6 +32,58 @@ import (
 	"github.com/siyuan-note/logging"
 )
 
+func ValidOptionalPort(port string) bool {
+	if port == "" {
+		return true
+	}
+	if port[0] != ':' {
+		return false
+	}
+	for _, b := range port[1:] {
+		if b < '0' || b > '9' {
+			return false
+		}
+	}
+	return true
+}
+
+func SplitHost(host string) (hostname, port string) {
+	hostname = host
+
+	colon := strings.LastIndexByte(hostname, ':')
+	if colon != -1 && ValidOptionalPort(hostname[colon:]) {
+		hostname, port = hostname[:colon], hostname[colon+1:]
+	}
+
+	if strings.HasPrefix(hostname, "[") && strings.HasSuffix(hostname, "]") {
+		hostname = hostname[1 : len(hostname)-1]
+	}
+
+	return
+}
+
+func IsLocalHostname(hostname string) bool {
+	if "localhost" == hostname {
+		return true
+	}
+	if ip := net.ParseIP(hostname); nil != ip {
+		return ip.IsLoopback()
+	}
+	return false
+}
+
+func IsLocalHost(host string) bool {
+	hostname, _ := SplitHost(host)
+	return IsLocalHostname(hostname)
+}
+
+func IsLocalOrigin(origin string) bool {
+	if url, err := url.Parse(origin); nil == err {
+		return IsLocalHostname(url.Hostname())
+	}
+	return false
+}
+
 func IsOnline(checkURL string, skipTlsVerify bool) bool {
 	_, err := url.Parse(checkURL)
 	if nil != err {