Electron - Invalid package on unzip

Question

For around 3 weeks I've been working on an Electron app and finally decided to get around to adding update checking. For my research, the standard way to do this in Electron (using Squirrel) requires the user to physically install the application onto their computer. I would rather not do this, and keep everything as portable as possible. I then decided to try making my own update script by having the program download the update.zip, and extract it to overwrite the existing files. This works well, up until the very end. At the very end of the extraction, I receive a Invalid package error, and the actual app.asar file is missing, rendering the application useless.

I am using this to download and extract the updates:

function downloadFile(url, target, fileName, cb) { // Downloads
    var req = request({
        method: 'GET',
        uri: url
    });

    var out = fs.createWriteStream(target+'/'+fileName);
    req.pipe(out);

    req.on('end', function() {
        unzip(target+'/'+fileName, target, function() {
            if (cb) {
                cb();
            }
        });
    });
}
function unzip(file, target, cb) { // Unzips

    var out = fs.createReadStream(file);
    out.pipe(unzipper.Extract({ path: target })).on('finish', function () {
        dialog.showMessageBox({
            type: 'question',
            message: 'Finished extracting to `'+target+'`'
        });

        if (cb) {
            cb();
        }
    });
}

And call it with:

downloadFile('http://example.com/update.zip', path.join(__dirname, './'), 'update.zip', function() { // http://example.com/update.zip is not the real source
    app.relaunch();
    app.quit();
});

And I use the unzipper NPM package (https://www.npmjs.com/package/unzipper).

The code works perfectly for all other zips, but it fails when trying to extract a zip containing an Electron app.

Anything I'm doing wrong, or maybe a different package that properly supports extracting zips with .asar files?

Edit 1 I just found https://www.npmjs.com/package/electron-basic-updater, which does not throw the same JavaScript error however it still does not extract the .asar files correctly, and will throw it's own error. Since the .asar is still missing, the app is still useless after the "update"

Answer 1

Thanks to your link to electron-basic-updater, I have found this issue mentioned there: https://github.com/TamkeenLMS/electron-basic-updater/issues/4.

They refer to the issue in the electron app: https://github.com/electron/electron/issues/9304.

Finally, in the end of the second topic there's a solution:

This is due to the electron fs module treating asar files as directories rather than files. To make the unzip process work you need to do one of two things:

• Set process.noAsar = true
• Use original-fs instead of fs

I have seen the people working with original-fs. But it looked like a big trouble to me.

So I tried setting process.noAsar = true (and then process.noAsar = false after unzipping) - and that worked like a charm.