Elm HTTP stream/chunk handling -- Elm n00b

[James_Smyth]

I’ve done a fair amount of research (ie. googling) and I’m not finding simple examples of how to use the Elm HTTP package, with what I think is the common paradigm, to process an http stream delivered in chunks(***). I’ve seen a few things indicating that I might have to do it using javascript (which i know quite well) and ports ( Ports · An Introduction to Elm (elm-lang.org) eh?), or maybe a ServiceWorker (familiar w/ that). I just want to make sure that there isn’t a prototypical way to do this in Elm that I haven’t stumbed on yet.

(*** There seems to be a fair amount of ambiguity on the interwebs about what https streaming/chunking means. My API responds w/
…
Content-Type: text/event-stream; charset=utf-8
Transfer-Encoding: chunked
…
12
ChunkLength12InHex
XX
ChunkLengthXXInHex…etc
…
0D
DoneIndicator

Which i can consume easily via fetch (NB: I’m aware that Elm HTTP package doesn’t use fetch…)
const reader = fetchResponse.body
.pipeThrough(new TextDecoderStream())
.getReader();
while (true) {
var { chunk, done } = await reader.read();
if (done) break;
DoSomethingWithChunk(chunk)
}
)

If I have to figure out how to implement this w/out using Elm HTTP, that’s fine, but I thought this might be a good place to ask for help to do it the correct way.

Thanks,
James

[szubtsovskiy]

Hi James,

My understanding is that you will need to use ports to achieve what you want. That’s what I would definitely do if I was solving a similar task.

Elm HTTP package provides a few handy functions to track progress but it won’t give you access to chunks, I believe, only to the number of bytes sent/received.