sending messages to the browser

lib/watercooler/www.ex

@@ -4,6 +4,7 @@ defmodule Watercooler.WWW do
   use Raxx.Router, [
     {%{method: :GET, path: []}, Watercooler.WWW.HomePage},
     {%{method: :POST, path: ["publish"]}, Watercooler.WWW.Publish},
+    {%{method: :GET, path: ["listen"]}, Watercooler.WWW.Listen},
     {_, Watercooler.WWW.NotFoundPage}
   ]
 

lib/watercooler/www/listen.ex

@@ -0,0 +1,21 @@
+defmodule Watercooler.WWW.Listen do
+  use Raxx.Server
+  alias ServerSentEvent, as: SSE
+
+  @impl Raxx.Server
+  def handle_request(_request, state) do
+    {:ok, _} = Watercooler.listen() # 1.
+
+    response = response(:ok)
+    |> set_header("content-type", SSE.mime_type())
+    |> set_body(true) # 2.
+
+    {[response], state} # 3.
+  end
+
+  @impl Raxx.Server
+  def handle_info({:watercooler, message}, state) do
+    event = SSE.serialize(message)
+    {[Raxx.data(event)], state} # 4.
+  end
+end

mix.exs

@@ -20,6 +20,7 @@ defmodule Watercooler.Mixfile do
       {:ace, "~> 0.16.4"},
       {:phoenix_html, "~> 2.11"},
       {:raxx_static, "~> 0.6.1"},
+      {:server_sent_event, "~> 0.3.1"},
       {:exsync, "~> 0.2.3", only: :dev},
     ]
   end

mix.lock

@@ -9,4 +9,5 @@
   "plug": {:hex, :plug, "1.5.1", "1ff35bdecfb616f1a2b1c935ab5e4c47303f866cb929d2a76f0541e553a58165", [:mix], [{:cowboy, "~> 1.0.1 or ~> 1.1 or ~> 2.3", [hex: :cowboy, repo: "hexpm", optional: true]}, {:mime, "~> 1.0", [hex: :mime, repo: "hexpm", optional: false]}], "hexpm"},
   "raxx": {:hex, :raxx, "0.15.4", "62e4a487e55e9469d1ba2d5de590672167f51eaac310f027f3f871018cb6a9fc", [:mix], [{:cookie, "~> 0.1.0", [hex: :cookie, repo: "hexpm", optional: false]}], "hexpm"},
   "raxx_static": {:hex, :raxx_static, "0.6.1", "8b48254fc3d1b8b1e473b7c307fbba0ae767c60482754ce823c664544c85d729", [:mix], [{:mime, "~> 1.1", [hex: :mime, repo: "hexpm", optional: false]}, {:raxx, "~> 0.15.2", [hex: :raxx, repo: "hexpm", optional: false]}], "hexpm"},
+  "server_sent_event": {:hex, :server_sent_event, "0.3.1", "4126788362090bfd542be90f65571c2b0155c7e4032bf557a4f91a34a563acc1", [:mix], [], "hexpm"},
 }