sse backend handler

#165

src/clj/swarmpit/handler.clj

@@ -25,6 +25,11 @@
   ([response] {:status 201
                :body   response}))
 
+(defn resp-accepted
+  ([] {:status 202})
+  ([response] {:status 202
+               :body   response}))
+
 ;;; Handler
 
 (defmulti dispatch identity)

src/clj/swarmpit/handler_sse.clj

@@ -0,0 +1,30 @@
+(ns swarmpit.handler-sse
+  (:require [org.httpkit.server :refer [run-server with-channel on-close send! close]]
+            [swarmpit.handler :refer [dispatch resp-accepted resp-error]]))
+
+(def channel-hub (atom {}))
+
+(defn broadcast [message]
+  (doseq [channel (keys @channel-hub)]
+    (send! channel message false)))
+
+(defmethod dispatch :events [_]
+  (fn [req]
+    (with-channel req channel
+                  (send! channel {:status  200
+                                  :headers {"Content-Type"                "text/event-stream"
+                                            "Access-Control-Allow-Origin" "*"
+                                            "Cache-Control"               "no-cache"
+                                            "Connection"                  "keep-alive"}
+                                  :body    ":ok\n\n"} false)
+                  (swap! channel-hub assoc channel req)
+                  (on-close channel (fn [_]
+                                      (swap! channel-hub dissoc channel))))))
+
+(defmethod dispatch :event-push [_]
+  (fn [{:keys [params]}]
+    (if (some? params)
+      (do
+        (broadcast (str "data: " params "\n\n"))
+        (resp-accepted (str "Broadcasted to " (count @channel-hub) " clients")))
+      (resp-error 400 "No event data send"))))