A lightweight WebSocket library for ClojureScript that uses core.async.
Add the following dependency to your deps.edn file:
haslett/haslett {:mvn/version "0.2.0"}
Or to your Leiningen project file:
[haslett "0.2.0"]
Haslett provides a simple and idiomatic interface to using WebSockets:
(ns example.core
(:require [cljs.core.async :as a :refer [<! >! go]]
[haslett.client :as ws]
[haslett.format :as fmt]))
(go (let [stream (<! (ws/connect "ws://echo.websocket.org"))]
(>! (:out stream) "Hello World")
(js/console.log (<! (:in stream)))
(ws/close stream)))The connect function returns a promise channel that produces a map
with four keys: :socket, :close-status, :in and :out.
-
:socketcontains the JavaScriptWebSocketobject, in case you need to access it directly. -
:close-statuscontains a promise channel that a status map is delivered to when the socket is closed. The status map will provide a:codeand:reasonkeys that will explain why the socket was closed. -
:inis a core.async channel to read from. -
:outis a core.async channel to write to.
By default, Haslett sends raw strings, but we can change that by supplying a formatter. Haslett includes formatters for JSON, edn and Transit:
(go (let [stream (<! (ws/connect "ws://echo.websocket.org" {:format fmt/transit}))]
(>! (:out stream) {:foo [1 2 3]})
(js/console.log (pr-str (<! (:in stream))))
(ws/close stream)))You can customize the behaviour further by supplying your own channels for the source and sink. This allows you to tune the channel buffer, and add transducers:
(ws/connect "ws://echo.websocket.org"
{:in (a/chan 10)
:out (a/chan 10)})When the WebSocket is closed, the :out and :in channels are
also closed. In addition, a final status map will be delivered to a
promise channel held in the :close-status key on the stream.
Copyright © 2024 James Reeves
Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.