Clojure EventSource client via java interop with Jersey SSE impl. (example uses firebase streaming api)

project.clj

(defproject sse-example "0.1.0-SNAPSHOT"
  :dependencies [[org.clojure/clojure "1.8.0"]
                 [cheshire "5.5.0"]
                 [org.glassfish.jersey.media/jersey-media-sse "2.22.2"]])

sse.clj

(ns sse
  (:require [cheshire.core :as json])
  (:import [javax.ws.rs.client ClientBuilder]
           [org.glassfish.jersey.media.sse EventSource EventListener SseFeature]))
                                         
(let [es (-> (ClientBuilder/newBuilder) (.register SseFeature) .build
             (.target "https://your-firebase-name.firebaseio.com.json")
             (.queryParam "auth" (into-array Object ["jwt/secret"]))
             EventSource/target .build)
        el (reify EventListener
             (onEvent [_ e]
               (println (.getName e) (json/decode (.readData e)))))]
    (.register es el)
    (.open es))