feat: connections inspection

1 files changed, 51 insertions, 0 deletions

diff --git a/src/api/connections.js b/src/api/connections.js
new file mode 100644
index 0000000..594fc5e
--- /dev/null
+++ b/src/api/connections.js
@@ -0,0 +1,51 @@
+const endpoint = '/connections';
+
+let fetched = false;
+let subscribers = [];
+
+function appendData(s) {
+  let o;
+  try {
+    o = JSON.parse(s);
+  } catch (err) {
+    // eslint-disable-next-line no-console
+    console.log('JSON.parse error', JSON.parse(s));
+  }
+  subscribers.forEach(f => f(o));
+}
+
+function getWsUrl(apiConfig) {
+  const { hostname, port, secret } = apiConfig;
+  let qs = '';
+  if (typeof secret === 'string' && secret !== '') {
+    qs += '?token=' + secret;
+  }
+  return `ws://${hostname}:${port}${endpoint}${qs}`;
+}
+
+let wsState;
+function fetchData(apiConfig, listener) {
+  if (fetched || wsState === 1) {
+    if (listener) return subscribe(listener);
+  }
+  wsState = 1;
+  const url = getWsUrl(apiConfig);
+  const ws = new WebSocket(url);
+  ws.addEventListener('error', function(_ev) {
+    wsState = 3;
+  });
+  ws.addEventListener('message', function(event) {
+    appendData(event.data);
+  });
+  if (listener) return subscribe(listener);
+}
+
+function subscribe(listener) {
+  subscribers.push(listener);
+  return function unsubscribe() {
+    const idx = subscribers.indexOf(listener);
+    subscribers.splice(idx, 1);
+  };
+}
+
+export { fetchData };