Rocket.Chat/apps/meteor/server/configuration/configureSMTP.ts

import type { ICachedSettings } from '../../app/settings/server/CachedSettings';
import { SystemLogger } from '../lib/logger/system';

export function configureSMTP(settings: ICachedSettings): void {
	settings.watchMultiple(
		['SMTP_Host', 'SMTP_Port', 'SMTP_Username', 'SMTP_Password', 'SMTP_Protocol', 'SMTP_Pool', 'SMTP_IgnoreTLS'],
		() => {
			SystemLogger.info('Updating process.env.MAIL_URL');

			if (!settings.get('SMTP_Host')) {
				delete process.env.MAIL_URL;
				return;
			}

			process.env.MAIL_URL = `${settings.get('SMTP_Protocol')}://`;

			if (settings.get('SMTP_Username') && settings.get('SMTP_Password')) {
				process.env.MAIL_URL += `${encodeURIComponent(settings.get('SMTP_Username'))}:${encodeURIComponent(settings.get('SMTP_Password'))}@`;
			}

			process.env.MAIL_URL += encodeURIComponent(settings.get('SMTP_Host'));

			if (settings.get('SMTP_Port')) {
				process.env.MAIL_URL += `:${parseInt(settings.get('SMTP_Port'))}`;
			}

			process.env.MAIL_URL += `?pool=${settings.get('SMTP_Pool')}`;

			if (settings.get('SMTP_Protocol') === 'smtp' && settings.get('SMTP_IgnoreTLS')) {
				process.env.MAIL_URL += '&secure=false&ignoreTLS=true';
			}
		},
	);
}