From 1216a517b7f725c787609db453eaa48f99c92918 Mon Sep 17 00:00:00 2001
From: Adam Hovorka <adamhovorka@gmail.com>
Date: Wed, 17 Jul 2019 23:23:52 -0600
Subject: Flesh out the WebSocket system with some amenities

---
 lib/socket.js | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 lib/socket.js

(limited to 'lib')

diff --git a/lib/socket.js b/lib/socket.js
new file mode 100644
index 0000000..971bacd
--- /dev/null
+++ b/lib/socket.js
@@ -0,0 +1,70 @@
+"use strict"
+
+const WebSocket = require("ws");
+
+class Client {
+  constructor(ws) {
+    this.ws = ws;
+    this.handlers = {};
+
+    ws.on("message", msg => { const d = JSON.parse(msg);
+      (this.handlers[d.type]||[]).forEach(cb => cb(d.data));
+    });
+
+    const closecb = () =>
+      (this.handlers["close"]||[]).forEach(cb => cb());
+
+    ws.on("close", closecb);
+    ws.on("error", closecb);
+  }
+
+  on(type, cb) {
+    (this.handlers[type]||(this.handlers[type]=[])).push(cb);
+  }
+
+  send(type, data) {
+    this.ws.send(JSON.stringify({type, data}));
+  }
+}
+
+module.exports = class Socket {
+  constructor(server) {
+    this.wss = new WebSocket.Server({server});
+    this.handlers = {};
+    this.clients = [];
+
+    this.wss.on("connection", ws => {
+      const client = new Client(ws);
+      this.clients.push(client);
+
+      ws.on("message", msg => { const d = JSON.parse(msg);
+        (this.handlers[d.type]||[]).forEach(cb => cb(client, d.data));
+      });
+
+      let pingTimeout;
+      const ping = () => { client.send("ping", {});
+        pingTimeout = setTimeout(() => ws.terminate(), 3e4); };
+      client.on("pong", () => { clearTimeout(pingTimeout);
+        setTimeout(ping, 1e3); }); ping();
+
+      const closecb = () => {
+        const i = this.clients.indexOf(client); if (i < 0) return;
+        (this.handlers["close"]||[]).forEach(cb => cb(client));
+        this.clients.splice(i, 1);
+      }
+
+      ws.on("close", closecb);
+      ws.on("error", closecb);
+
+      (this.handlers["open"]||[]).forEach(cb => cb(client));
+    });
+  }
+
+  on(type, cb) {
+    (this.handlers[type]||(this.handlers[type]=[])).push(cb);
+  }
+
+  sendAll(type, data) {
+    this.clients.forEach(c => c.send(type, data));
+  }
+};
-- 
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