How to download incoming file and prevent Backpressure while sending files through WebRTC data channels using streams?

Question

I'm building a file sharing application with WebRTC and Node.js. It is a command line application so there will be no HTML invloved. I'm reading the file as a stream and sending it, then at reciever's side I'll download the file. Here's how I'll be writing the sender's code :

        // code taken from https://github.com/coding-with-chaim/file-transfer- 
        // final/blob/master/client/src/routes/Room.js

        const reader = stream.getReader();

        reader.read().then(obj => {
            handlereading(obj.done, obj.value);
        });

        // recursive function for sending out chunks of stream
        function handlereading(done, value) {
            if (done) {
                peer.write(JSON.stringify({ done: true, fileName: file.name }));
                return;
            }

            peer.write(value);
            reader.read().then(obj => {
                handlereading(obj.done, obj.value);
            })
        }

On the reciever's side I'll be converting the incoming file (stream) to Blob but people online are saying that there will be an issue of backpressure if the size of the file is too large. How should I write the file dowloading code to avoid backpressure so that it doesn't crash the reciever's side due to buffer overflow? Or should there be another approach to downloading the file?

Answer 1

You want to listen to onbufferedamountlow after setting bufferedAmountLowThreshold

You will want to put all your logic on the sender side, the receiver doesn't have any control. I think MDN is your best resource, I didn't find any good single article on this.

I do have an example in Pion here but that is in Go. The same concept though so hopefully helpful!