YouTube API, Version 3 on Rails

@bodrovis - no problem

I have one follow-up question around validating video uploads.
With this structure, how would you implement file size validations for video uploads?
We only want to allow short videos e.g. < 60 secs in length and to begin with want to set an arbitrary file size limit of 50MB.

We have explored trying to add explicit validations within the video_upload.rb ActiveType::Object but to no avail.
e.g. validates_size_of :file, maximum: 50.megabytes, message: "should be less than 50MB"
I understand how you could achieve this using a third party uploader like CarrierWave but struggling to see how you could do this here.

Any thoughts would be greatly appreciated!

Thanks,
Alex