refactoring

Resolve #7779

packages/backend/src/misc/convert-host.ts

@@ -0,0 +1,26 @@
+import { URL } from 'url';
+import config from '@/config/index';
+import { toASCII } from 'punycode/';
+
+export function getFullApAccount(username: string, host: string | null) {
+	return host ? `${username}@${toPuny(host)}` : `${username}@${toPuny(config.host)}`;
+}
+
+export function isSelfHost(host: string) {
+	if (host == null) return true;
+	return toPuny(config.host) === toPuny(host);
+}
+
+export function extractDbHost(uri: string) {
+	const url = new URL(uri);
+	return toPuny(url.hostname);
+}
+
+export function toPuny(host: string) {
+	return toASCII(host.toLowerCase());
+}
+
+export function toPunyNullable(host: string | null | undefined): string | null {
+	if (host == null) return null;
+	return toASCII(host.toLowerCase());
+}