support callback which will only called once before upload

[oeway]

As mentioned in #207, currently, onBeforeUpload will called on each chunk upload, which could raise potential performance drop if some expensive operation is contained in onBeforeUpload. Would be great to support callback which would only execute once, either by change the current onBeforeUpload or add something like onInitiateUpload.

[dr-dimitru]

I'll stay with onInitiateUpload. As changing onBeforeUpload current behaviour, may break some current usage, or will request Major version release

[dr-dimitru]

Implemented in v1.7.2

[oeway]

@dr-dimitru It worked, but it seems that the returned value from onInitiateUpload is not used to reject a upload?

[oeway]

However, I can throw new Meteor.Error('not-authorized'); in onInitiateUpload to stop the upload.

[dr-dimitru]

Why not use onBeforeUpload to control/stop/continue upload?
onInitiateUpload is create for purpose you've described - if some expensive operation is contained. And it's asynchronous, throwing an exception will stop nodejs process, but it might be somewhere in the middle or at the end of upload

[livimonte]

It would be better to make the file validation (check weight and extension for example) in onInitiateUpload instead of onBeforeUpload? Since that runs only once and before starting the upload.

[dr-dimitru]

This will be removed in v2.0
As it comes from early stages of this package it may break someone's integration

It was done this way to protect unfinished uploads from fraud actions. As previously was no control of uploaded size, currently any size overflow will abort upload.

[HungryJake]

I've looked into the code, seems like onInitiateUpload is not being called if onBeforeUpload is not being defined, is this done intentionally?

[dr-dimitru]

@livimonte onBeforeUpload is made this way to avoid file mitigation during upload

[dr-dimitru]

@DrkCoater you right, this shouldn't be this way.
Fix will be released soon see this commit, thank you