From 21dd9ccf7ecc2a1b17482b36f2aeefe63d21c439 Mon Sep 17 00:00:00 2001
From: nvms <jon@pye.rs>
Date: Mon, 21 Apr 2025 10:39:48 -0400
Subject: [PATCH] feat(server): assign short unique connection IDs using custom
 generator

---
 packages/mesh/src/server/connection.ts |  5 ++-
 packages/mesh/src/server/utils/ids.ts  | 47 ++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100644 packages/mesh/src/server/utils/ids.ts

diff --git a/packages/mesh/src/server/connection.ts b/packages/mesh/src/server/connection.ts
index ad1eeaa..43328d7 100644
--- a/packages/mesh/src/server/connection.ts
+++ b/packages/mesh/src/server/connection.ts
@@ -10,6 +10,9 @@ import { Status } from "../common/status";
 import { Latency } from "./latency";
 import { Ping } from "./ping";
 import type { MeshServerOptions } from "./";
+import { getCreateId } from "./utils/ids";
+
+const getId = getCreateId({ init: Date.now(), len: 4 });
 
 export class Connection extends EventEmitter {
   id: string;
@@ -29,7 +32,7 @@ export class Connection extends EventEmitter {
   ) {
     super();
     this.socket = socket;
-    this.id = req.headers["sec-websocket-key"]!;
+    this.id = getId();
     this.remoteAddress = req.socket.remoteAddress!;
     this.connectionOptions = options;
 
diff --git a/packages/mesh/src/server/utils/ids.ts b/packages/mesh/src/server/utils/ids.ts
new file mode 100644
index 0000000..692149f
--- /dev/null
+++ b/packages/mesh/src/server/utils/ids.ts
@@ -0,0 +1,47 @@
+import { getRandomValues } from "node:crypto";
+
+const HEX: string[] = [];
+
+for (let i = 0; i < 256; i++) {
+  HEX[i] = (i + 256).toString(16).substring(1);
+}
+
+function pad(str: string, size: number) {
+  const s = `000000${str}`;
+  return s.substring(s.length - size);
+}
+
+const SHARD_COUNT = 32;
+
+export function getCreateId(opts: { init: number; len: number }) {
+  const len = opts.len || 16;
+  let str = "";
+  let num = 0;
+  const discreteValues = 1_679_616; // Math.pow(36, 4)
+  let current = opts.init + Math.ceil(discreteValues / 2);
+
+  function counter() {
+    if (current >= discreteValues) current = 0;
+    current++;
+    return (current - 1).toString(16);
+  }
+
+  return () => {
+    if (!str || num === 256) {
+      const bytes = new Uint8Array(len);
+      getRandomValues(bytes);
+      str = Array.from(bytes, (b) => HEX[b])
+        .join("")
+        .substring(0, len);
+      num = 0;
+    }
+
+    const date = Date.now().toString(36);
+    const paddedCounter = pad(counter(), 6);
+    const hex = HEX[num++]!;
+
+    const shardKey = parseInt(hex, 16) % SHARD_COUNT;
+
+    return `conn-${date}${paddedCounter}${hex}${str}${shardKey}`;
+  };
+}