Store size in packages property

[adam-lynch]

Store size in packages property

[edjafarov]

this is awesome idea! I had an issue with zipped mac. I will try smth like that.

[adam-lynch]

Should this module handle this though?

Or should we just suggest users to add it to the packages field and to make sure and check it with fs.statSync before running updater.download?

Or we could add a public method which will validate it?

[edjafarov]

To download packages we are using request, we can get headers content-length to know the size of package. Then we can compare with what we have on filesystem, right?

[adam-lynch]

Oh ya, didn't think of that. But when do we do the check?

[edjafarov]

I would say somewhere https://github.com/edjafarov/node-webkit-updater/blob/master/app/updater.js#L66 here. Right after the package was downloaded.

[adam-lynch]

Ok. I was also thinking about the chance that the size of the file on disk might not be the right size by the time the unpacking was done (let's say you download updates in the background and the user updates whenever they decide). But I don't think this is worth worrying about.

[adam-lynch]

Wait, what if I kill my nw.exe while the download is ongoing? This check will never be done right?

Let's say when I get the manifest, but downloading a package, I first check if it already exists in the temp directory, it could be there but the file size would be wrong (i.e. corrupted). Because of this case, would it make sense for the user to be able to validate the already downloaded package?

Again, keep in mind, I don't know much about corrupted downloads.

[edjafarov]

Well. We are talking about package, right? zip
This is one file. I assume that it has a length. And if the length is right then this is it. The package is not corrupted. And high chances are that it will be unpacked properly.
Checksum would be more awesome, but that would require additional requirements for server that would handle the packages.

[adam-lynch]

And if the length is right then this is it.

If I start the download, kill my node-webkit app (and therefore the download). Then I want to unpack it later, do we know "the length is right"?

Even if the user was told of the file length to expected, before the download is started. A callback or something. Then I could save that somewhere, so I can look it up later and compare it to the actual file size.

[edjafarov]

well I assume you won't be able to start from unpacking if you killed the app during downloading.
You still have old app in your folder thus it will check that there is difference in versions and would start downloading.

[adam-lynch]

I'm in the middle of building a update system for my node-webkit app. When it downloads an update, it keeps track filepath. Then if at any point it tries to download it again, it first checks does it already exist.

So, the download is started, the download is killed (my download callback is never called), but the next time it tries to download, it looks in the temp directory and it already exists.

I guess I need to persist the filepath in localStorage or something and then when I check if it already exists before downloading, I need to check localStorage too and if it's not there, then I delete it from the temp dir and re-download.

I think that makes sense so.

I can try adding the bit where it validates the size against the header after downloading today.

[edjafarov]

yeah, you right. Let the updater be lower level. At least it would tell you that the downloaded package is valid. What would you do with that information is your business.
You also can move the file to specific temp folder if it was downloaded properly/completely.

[adam-lynch]

Yeah, good idea.

[edjafarov]

was it fixed?

[adam-lynch]

The advice should be to move the download to another folder when done.

Since I now check for the statusCode of the response, this won't download 0KB files for 404s, etc.

From my quick research, request don't seem to advise / allow you to get the content-length and check it afterwards. I can't remember the other reasons, but moving to another folder and checking the response code is enough.

[edjafarov]

ok