Allow large file download and upload using the Reactive REST Client.

[cescoffier]

Description

Allow large file downloads and uploads using the Reactive REST Client.
Large means that the file size does not fit in memory and back-pressure must be used.
Typically it would allow passing a Multi as a parameter or receiving a Multi.

• sending Multi<Byte> as file
• receiving files as Multi<Byte>

[quarkus-bot]

/cc @michalszynkiewicz

[michalszynkiewicz]

sending done in #21569

[michalszynkiewicz]

receiving multipart files as Multi is troublesome.
If there is more than one field in a multipart message, and a user wants to read a field that is after the file first, they won't be able to if we want to do it right.
A solution for it would be storing the downloaded files on disk before giving the control back to the user. WDYT @cescoffier ?

[cescoffier]

it's reasonable, and then back-pressure will apply from the file system.

[michalszynkiewicz]

TBH I don't remember if download wasn't implemented too.
For sure we're missing sending/receiving files as Multi<Byte[]> which would perform better.

CC @Sgitario

[geoand]

@Sgitario you have fixed various things around this, correct?
Can you please have a look and see if this has been properly addressed?

[Sgitario]

Receiving files using Multi<Byte> is still not supported, so we can't close this issue yet.

[geoand]

Okay, thanks

[gastaldi]

@geoand Is this issue still valid?

[geoand]

I think so