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

import http from 'http';
import https from 'https';
import fs from 'fs';

import { Meteor } from 'meteor/meteor';

import { RocketChatImportFileInstance } from '../startup/store';
import { ProgressStep } from '../../lib/ImporterProgressStep';
import { hasPermission } from '../../../authorization';
import { Importers } from '..';

function downloadHttpFile(fileUrl, writeStream) {
	const protocol = fileUrl.startsWith('https') ? https : http;
	protocol.get(fileUrl, function(response) {
		response.pipe(writeStream);
	});
}

function copyLocalFile(filePath, writeStream) {
	const readStream = fs.createReadStream(filePath);
	readStream.pipe(writeStream);
}

Meteor.methods({
	downloadPublicImportFile(fileUrl, importerKey) {
		const userId = Meteor.userId();

		if (!userId) {
			throw new Meteor.Error('error-invalid-user', 'Invalid user', { method: 'downloadPublicImportFile' });
		}

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

		const importer = Importers.get(importerKey);
		if (!importer) {
			throw new Meteor.Error('error-importer-not-defined', `The importer (${ importerKey }) has no import class defined.`, { method: 'downloadPublicImportFile' });
		}

		const isUrl = fileUrl.startsWith('http');

		// Check if it's a valid url or path before creating a new import record
		if (!isUrl) {
			if (!fs.existsSync(fileUrl)) {
				throw new Meteor.Error('error-import-file-missing', fileUrl, { method: 'downloadPublicImportFile' });
			}
		}

		importer.instance = new importer.importer(importer); // eslint-disable-line new-cap

		const oldFileName = fileUrl.substring(fileUrl.lastIndexOf('/') + 1);
		const date = new Date();
		const dateStr = `${ date.getUTCFullYear() }${ date.getUTCMonth() }${ date.getUTCDate() }${ date.getUTCHours() }${ date.getUTCMinutes() }${ date.getUTCSeconds() }`;
		const newFileName = `${ dateStr }_${ userId }_${ oldFileName }`;

		// Store the file name on the imports collection
		importer.instance.startFileUpload(newFileName);
		importer.instance.updateProgress(ProgressStep.DOWNLOADING_FILE);

		const writeStream = RocketChatImportFileInstance.createWriteStream(newFileName);

		writeStream.on('error', Meteor.bindEnvironment(() => {
			importer.instance.updateProgress(ProgressStep.ERROR);
		}));

		writeStream.on('end', Meteor.bindEnvironment(() => {
			importer.instance.updateProgress(ProgressStep.FILE_LOADED);
		}));

		if (isUrl) {
			downloadHttpFile(fileUrl, writeStream);
		} else {
			// If the url is actually a folder path on the current machine, skip moving it to the file store
			if (fs.statSync(fileUrl).isDirectory()) {
				importer.instance.updateRecord({ file: fileUrl });
				importer.instance.updateProgress(ProgressStep.FILE_LOADED);
				return;
			}

			copyLocalFile(fileUrl, writeStream);
		}
	},
});