Unexpected multiple requests with file upload

Technical Q&A
1

SmartClient Version: v13.1p_2026-04-24/AllModules Development Only (built 2026-04-24)

Hi, from the documentation: “Due to browser security restrictions, at most one request with a file upload can be sent in a queue.”

However, I’m seeing that this doesn’t seem to be the case.

With the following use case, if I fill in the fields and select a file, I see two separate requests, without any queue (and no warnings in the dev console):

isc.DynamicForm.create({
    ID: "aForm",
    width: 400,
    height: 100,
    top: 0,
    left: 20,
    dataSource: "uploadTest",
    items: [
        {name: "title"}
    ]
});

isc.DynamicForm.create({
    ID: "uploadForm",
    width: 400,
    height: 100,
    top: 50,
    left: 20,
    dataSource: "uploadedFiles",
    items: [
        {name: "uploadTestId"},
        {name: "file", title: "File"}
    ]
});


isc.Button.create({
    title: "Save Form",
    top: 130,
    left: 20,
    click: function(){
        isc.RPCManager.startQueue()
        aForm.save()
        uploadForm.save()
        isc.RPCManager.sendQueue()
    }
});

I’m not sure whether there’s an issue or if I’m missing something.

2

That’s what the docs are saying: a maximum of one file can be sent in a queue, so the two requests have to be sent separately.

Note we’re getting around this in later versions, but for 13.1, this limitation is correct.

3

Thanks for the clarification, I was interpreting that sentence differently - as allowing multiple requests in the queue, with the only constraint being a maximum of one request containing a file upload.

Good to know that this limitation is being addressed in newer versions, that will definitely be a nice improvement.