Make the streaming API also handle websockets (because trying to get the browser EventSource interface to

work flawlessly was a nightmare). WARNING: This commit makes the web UI connect to the streaming API instead
of ActionCable like before. This means that if you are upgrading, you should set that up beforehand.

app/assets/javascripts/components/stream.jsx

@@ -0,0 +1,21 @@
+import WebSocketClient from 'websocket.js';
+
+const createWebSocketURL = (url) => {
+  const a = document.createElement('a');
+
+  a.href     = url;
+  a.href     = a.href;
+  a.protocol = a.protocol.replace('http', 'ws');
+
+  return a.href;
+};
+
+export default function getStream(accessToken, stream, { connected, received, disconnected }) {
+  const ws = new WebSocketClient(`${createWebSocketURL(STREAMING_API_BASE_URL)}/api/v1/streaming/?access_token=${accessToken}&stream=${stream}`);
+
+  ws.onopen    = connected;
+  ws.onmessage = e => received(JSON.parse(e.data));
+  ws.onclose   = disconnected;
+
+  return ws;
+};