Update GridFS exmaple code

[harryadel]

Hello this is a problem I ran into during our migration and I thought it'd be nice to document so others could avoid this pitfall.

First off, the internal API for objectId got changed. Meteor even caught on this and updated their code.

Second, there was a silent fail with this piece of code:

.on('finish', async (ver) => {
	const property = `versions.${versionName}.meta.gridFsFileId`
	await self.collection.updateAsync(file._id, {
	    $set: {
	        [property]: ver._id.toHexString(),
	    },
})

ver is undefined so it fails to associate the new gridFS instance. Maybe due to internal mongo versions problem. The code had to be modified so the the gridFS id is stored in the return value of openUploadStream

const uploadStream = bucket
        .openUploadStream(file.name, {
            contentType: file.type || 'binary/octet-stream',
            metadata,
        })

[dr-dimitru]

@harryadel thank you for spotting this issue! Please see my questions regarding implementation

[dr-dimitru]

Can we create uploadStream above readStream? Outside open event?

[dr-dimitru]

Can we register these events when uploadStream variable created and before passing it to pipe ?

[dr-dimitru]

Got to update to new await unlinkAsync

[dr-dimitru]

@harryadel lmk if we can push this one through, I'm finishing with docs

[harryadel]

@dr-dimitru Ok, I'll look at today so we can finalize it. 👍

[harryadel]

Hey @dr-dimitru, please re-check

I took time because I wanted to do this in an example app to verify that our changes are indeed correct and not fix some imaginary code. The test repo is here in case you wanna check it out or even include as an example.