fast-twitch.server.sse

Using this namespace

(ns application.events
  (:require [fast-twitch.server.sse :as sse]))

(defn events-handler [_]
  (let [remaining (atom [{:data "one"} {:event "notice" :data "two"}])]
    (sse/response
      (fn []
        (let [event (first @remaining)]
          (swap! remaining next)
          event)))))

response accepts [next-event] or [next-event options] and returns a Ring response map. The zero-argument producer can return a Promise. Returning nil ends the stream. Allocate producer cursors inside the handler so concurrent responses cannot consume each other's events.

An event requires string :data; optional fields are :event, :id and :retry. See exact event restrictions. Producer normal completion needs its own cleanup; :on-cancel is not called on ordinary EOF. Pulls await one event at a time with a zero high-water mark.

Runnable producer and both consumers · Generic SSE versus Datastar.

Upstream function reference

Pull-based SSE responses for ordinary Ring handlers.

response

(response next-event)
(response next-event options)

Function. Source