Rocket.Chat/app/importer/server/methods/prepareImport.js

import { Meteor } from 'meteor/meteor';
import { check } from 'meteor/check';

import { Importers } from '..';

import { hasPermission } from '../../../authorization';

Meteor.methods({
	prepareImport(key, dataURI, contentType, fileName) {
		if (!Meteor.userId()) {
			throw new Meteor.Error('error-invalid-user', 'Invalid user', { method: 'prepareImport' });
		}

		if (!hasPermission(Meteor.userId(), 'run-import')) {
			throw new Meteor.Error('error-action-not-allowed', 'Importing is not allowed', { method: 'setupImporter' });
		}

		check(key, String);
		check(dataURI, String);
		check(fileName, String);

		const importer = Importers.get(key);

		if (!importer) {
			throw new Meteor.Error('error-importer-not-defined', `The importer (${ key }) has no import class defined.`, { method: 'prepareImport' });
		}

		const results = importer.instance.prepare(dataURI, contentType, fileName);

		if (results instanceof Promise) {
			return results.catch((e) => { throw new Meteor.Error(e); });
		}
		return results;
	},
});