Upload multiple files with quarkus-rest-client

[kronst]

I'm currently trying to migrate from quarkus-resteasy to quarkus-rest and can't find a proper way of sending mutliple files as streams using registered client without loading them in memory.
Previously I was using org.jboss.resteasy.plugins.providers.multipart.MultipartFormDataOutput, but not sure if it's supported in quarkus-rest-client.

I found that there is a recommended way of using ClientMultipartForm to send multipart request.
According to the docs ClientMultipartForm accepts Buffer which can be created from byte array. But this approach is not suitable for me, because I want to avoid of loading all the files in memory.

[quarkus-bot[bot]]

/cc @cescoffier (rest-client), @geoand (rest-client)

[geoand]

@kronst what did you code quarkus-resteasy code look like?

[kronst]

Sure, here is an example of how it looks like

// Client interface method
import org.jboss.resteasy.annotations.providers.multipart.MultipartForm
import org.jboss.resteasy.plugins.providers.multipart.MultipartFormDataOutput

@POST
@Path("/messages")
@Consumes(MediaType.MULTIPART_FORM_DATA)
MessageResponseDTO sendMessage(
    @HeaderParam("Authorization") String authorization,
    @MultipartForm MultipartFormDataOutput payload
);

// Usage of the client
public MessageResponseDTO sendMessage(SendMessageDTO payload) {
    MultipartFormDataOutput form = new MultipartFormDataOutput();
    form.addFormData("message", payload.getMessage(), MediaType.APPLICATION_JSON_TYPE);

    for (Attachment attachment : payload.getAttachments()) {
        form.addFormData(
            attachment.getId(),
            attachment.getData(), // InputStream
            MediaType.APPLICATION_OCTET_STREAM_TYPE,
            attachment.getFilename()
        );
    }

    return client.sendMessage(authHeader(), form);
}

[geoand]

Thanks a lot. I'll have to look and see what we can do.

[geoand]

I took a look at what goes on from Quarkus, to Vert.x and down to Netty and it seems that the only fool proof way of making this work is to actually use a file. Everything else is going to end up pilling up in memory

[kronst]

Please, correct me if I'm wrong.
I've taken a look at the sources again after your messages about the File usage and came to a QuarkusMultipartFormUpload which uses anonymous DefaultHttpDataFactory to create MixedFileUpload (DiskFileUpload as a result). As I see this upload type reads file with chunks into ByteBuf.
So do you mean that I could write my streams into temp files and use them in ClientMultipartForm?

[geoand]

Yeah, that should work

[kronst]

Okay, will try this approach.

Bwt, if I'm not mistaken your improvement in #47823 will allow to send multiple InputStreams in a single request body using quarkus-rest-client.

[geoand]

Unfortunately that still buffers in memory :(

[kronst]

Oh... That's a pity 😕
Anyway, thanks a lot for your time and for the answers.