Protocols to push data about httpmq

[alwitt]

Hi @gedw99, thanks for the interest.

In my original design, I wanted the client to server communication to be over the same request stream as the SSE. I had the following demo code working locally.

However, when I started testing in Kubernetes, I was not able to get this working through my Ingress controller (Traefik in my case); I had validated through kubectl portforward that the connection still worked correctly. I have not tested other ingress controller yet.

I am also not sure whether this full duplex would work without HTTP 2, as some proxies I use don't support that. So I decided to split the client to server communication from the server to client stream.

I don't have much experience using SSE between front-end and back-end; I have always used Websockets. So I am curious how other people use SSE.

---

Server Request Handler

fullDuplexHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	// First flash response headers
	if f, ok := w.(http.Flusher); ok {
		f.Flush()
	}
	// Copy from the request body to the response writer and flush
	// (send to client)
	if _, err := io.Copy(flushWriter{w: w}, r.Body); err != nil {
		log.WithError(err).Error("Full-Duplex")
		w.WriteHeader(500)
	}
})

Client Side

// Create a pipe - an object that implements `io.Reader` and `io.Writer`.
// Whatever is written to the writer part will be read by the reader part.
pr, pw := io.Pipe()

client := http.Client{}

// Create an `http.Request` and set its body as the reader part of the
// pipe - after sending the request, whatever will be written to the pipe,
// will be sent as the request body.
// This makes the request content dynamic, so we don't need to define it
// before sending the request.

resp, err := client.Post(args.URL, "text", ioutil.NopCloser(pr))
// Send the request
log.Infof("Send POST to %s", args.URL)
if err != nil {
	return (err)
}
log.Infof("POST Got: %d", resp.StatusCode)

// Run a loop which writes every second to the writer part of the pipe
// the current time.
go func() {
	for {
		log.Info("Writing to server")
		time.Sleep(time.Second)
		fmt.Fprintf(pw, "It is now %v\n", time.Now())
	}
}()

// Copy the server's response to stdout.
_, err = io.Copy(os.Stdout, resp.Body)

[gedw99]

I have used SSE . Pocketbase a popular golang project used them. Can probably look at that later if we want to give it another try .

Do you currently use web sockets instead over http2 ?

[alwitt]

PocketBase looks like a very interesting project. I will take a look later.

I use websockets in my other projects. This project uses HTTP1.1 / HTTP2.

[gedw99]

So there is no push currently

Mhh . Best to use nats

[alwitt]

Unfortunately, there is no plans to transition to web-sockets at the moment.

I am using this project as apart of another project, so the design decision is partly driven by the needs of that project.

[gedw99]

Ok thanks

I think I can extend it without forking to incorporate nats.

[alwitt]

Sounds good. Let me know if you have any other questions about the project.

[gedw99]

Unfortunately, there is no plans to transition to web-sockets at the moment.

I am using this project as apart of another project, so the design decision is partly driven by the needs of that project.

Yep makes sense ...

But i realised i was lazy with me writing....
I meant the inherent websockets of NATS Jetstream can be turned.

For the data plane it's just a matter of turning it on. THen clients no nats.go dependency can get events sent to them from nats.

I currently use nats.go for projects of Web clients, Desktops and Servers. The Web client is the nats.go compiled to wasm. Call me pessimistic but i wanted feature parity for Web and Non web clients to use the same code.

[gedw99]

Unfortunately, there is no plans to transition to web-sockets at the moment.

I am using this project as apart of another project, so the design decision is partly driven by the needs of that project.

I meant the inherent websockets of NATS Jetstream.

For the Control plane it's just a matter of turning it on.
I currently use this for Web clients, Desktops and Servers. The Web cleit is the nats.go compiled to wasm. Call me nuts but i wants the Web and Non web clients to use the same code..