ring VS ketu

* HTTP: Ring is the de facto way to manage HTTP request (see https://github.com/ring-clojure/ring/wiki/Concepts). Jetty and Aleph are common web servers (and https://github.com/clj-commons/aleph) that implement Ring interface.

https://youtu.be/LcpbBth7FaQ (really cool live coding session with REPL-driven development for a ring web app)

> In the HTTP handlers it makes sense that you don't have return values, because: What would you do with that value exactly?

I think that approach used by clojure's ring shows an elegant way to represent http responses https://github.com/ring-clojure/ring/wiki/Concepts#responses. They are essentially structs with the following fields:

status := number

headers := map of string->string

body := stream | string | seq | inputstream

Request handlers are handed a request struct that is similar. The handler is a function that maps a request to a response (it doesn't actually write to streams itself).

I like this style for an http library for a couple of reasons:

1. HTTP resources can be viewed as functions whose domain is the request, and range is the response. Having the abstraction match that makes for really nice code.

While you won't find your Spring here, you will find that many of those web libraries will tend to use or produce Hiccup, return Ring maps or maybe have pipelines built using interceptors. Composing libraries together is usually not that hard, but it does require you to leave the comfort zone of the framework's abstractions to try to understand what is actually happening e.g. when someone makes an HTTP request and something is returned and displayed in the browser.

On that note, are you able to support everything required by the ring spec?

You can check out my example project in Clojure with using Ring.

It uses already mentioned ring api (https://github.com/ring-clojure/ring/wiki).

I've tried to pair down to the simplest example which shows the issue, and raised it here as I couldn't see one you'd already created or similar: https://github.com/ring-clojure/ring/issues/436 This is so that I have something to link to/follow from our side, hope you don't mind, and many thanks for the diagnosis!

Designating a single thread to act as a consumer would work, but it's probably easier to use a library like ketu, which is an async Clojure client for Kafka.