Rocket.Chat/app/api/server/helpers/getLoggedInUser.js

import { Accounts } from 'meteor/accounts-base';

import { Users } from '../../../models';
import { API } from '../api';

API.helperMethods.set('getLoggedInUser', function _getLoggedInUser() {
	let user;

	if (this.request.headers['x-auth-token'] && this.request.headers['x-user-id']) {
		user = Users.findOne({
			_id: this.request.headers['x-user-id'],
			'services.resume.loginTokens.hashedToken': Accounts._hashLoginToken(this.request.headers['x-auth-token']),
		});
	}

	return user;
});