Upload Field

[felixoi]

Describe your motivation

Currently it is possible to upload files using the upload component. Still like it's implemented it's not as easy to use it in forms with a binder.

Describe the solution you'd like

A first class upload component which is bindable.

Describe alternatives you've considered

Using addons and other external implementations.

Additional context

[Legioth]

What would the value type of that field be? Just based on a quick overview I could imagine either of byte[], InputStream, OutputStream, String (filesystem path of an uploaded file) or java.sql.Blob and I'm quite sure there are also other candidates if you dig slightly deeper.

[felixoi]

That's actually a good question. From a simple perspective I'd have expected byte[]. Still I can understand why you are listing the others too.

[Legioth]

The problem with byte[] is that it forces always keeping the data in memory. I wonder if Supplier<byte[]> would be a decent way of working around that without making simple cases too cumbersome?

[mshabarov]

Deserves perhaps a new component that implements HasValue and provides a generic value type, but also allows to set a supplier that converts the InputStream (stream resource output) to the generic type of this component.

[web-padawan]

This was previously requested in #1571. See also #1571 (comment) for how to wrap Upload in CustomField.

[felixoi]

I know that I can wrap it and we have it in live in action. It's always a struggle tho to update it and just maintain it (also for multi file uploads). As of my knowledge the majority of huge frameworks have this functionality just out of the box, so that's why I'm requesting it again. It's simple to build nice form with vaadin but at the point you want to include file uploads, it's always a struggle (we're having multiple vaadin apps live in production which have a lot of forms).