feat: universal access to all peers (#60)

2025-12-06 04:19:26 +00:00 · 2024-08-06 14:35:33 +02:00
parent bb4c9175e4
commit 7fa9976584
17 changed files with 256 additions and 84 deletions
--- a/src/adapters/bun.ts
+++ b/src/adapters/bun.ts
@@ -3,11 +3,15 @@
 import type { WebSocketHandler, ServerWebSocket, Server } from "bun";
 import { Message } from "../message";
 import { Peer } from "../peer";
-import { AdapterOptions, defineWebSocketAdapter } from "../types";
+import {
+  AdapterOptions,
+  AdapterInstance,
+  defineWebSocketAdapter,
+} from "../types";
 import { AdapterHookable } from "../hooks";
 import { toBufferLike } from "../_utils";

-export interface BunAdapter {
+export interface BunAdapter extends AdapterInstance {
  websocket: WebSocketHandler<ContextData>;
  handleUpgrade(req: Request, server: Server): Promise<Response | undefined>;
 }
@@ -15,7 +19,7 @@ export interface BunAdapter {
 export interface BunOptions extends AdapterOptions {}

 type ContextData = {
-  _peer?: Peer;
+  _peer?: BunPeer;
  request?: Request;
  requestUrl?: string;
  server?: Server;
@@ -24,7 +28,9 @@ type ContextData = {
 export default defineWebSocketAdapter<BunAdapter, BunOptions>(
  (options = {}) => {
    const hooks = new AdapterHookable(options);
+    const peers = new Set<BunPeer>();
    return {
+      peers,
      async handleUpgrade(request, server) {
        const res = await hooks.callHook("upgrade", request);
        if (res instanceof Response) {
@@ -38,34 +44,37 @@ export default defineWebSocketAdapter<BunAdapter, BunOptions>(
          } satisfies ContextData,
          headers: res?.headers,
        });
-        return upgradeOK
-          ? undefined
-          : new Response("Upgrade failed", { status: 500 });
+        if (!upgradeOK) {
+          return new Response("Upgrade failed", { status: 500 });
+        }
      },
      websocket: {
        message: (ws, message) => {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
          hooks.callHook("message", peer, new Message(message));
        },
        open: (ws) => {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
+          peers.add(peer);
+          hooks.callAdapterHook("bun:open", peer, ws);
          hooks.callHook("open", peer);
        },
        close: (ws) => {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
+          peers.delete(peer);
          hooks.callAdapterHook("bun:close", peer, ws);
          hooks.callHook("close", peer, {});
        },
        drain: (ws) => {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
          hooks.callAdapterHook("bun:drain", peer);
        },
        ping(ws, data) {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
          hooks.callAdapterHook("bun:ping", peer, ws, data);
        },
        pong(ws, data) {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
          hooks.callAdapterHook("bun:pong", peer, ws, data);
        },
      },
@@ -73,11 +82,14 @@ export default defineWebSocketAdapter<BunAdapter, BunOptions>(
  },
 );

-function getPeer(ws: ServerWebSocket<ContextData>) {
+function getPeer(
+  ws: ServerWebSocket<ContextData>,
+  peers: Set<BunPeer>,
+): BunPeer {
  if (ws.data?._peer) {
    return ws.data._peer;
  }
-  const peer = new BunPeer({ bun: { ws } });
+  const peer = new BunPeer({ peers, bun: { ws } });
  ws.data = {
    ...ws.data,
    _peer: peer,
@@ -86,6 +98,7 @@ function getPeer(ws: ServerWebSocket<ContextData>) {
 }

 class BunPeer extends Peer<{
+  peers: Set<BunPeer>;
  bun: { ws: ServerWebSocket<ContextData> };
 }> {
  get addr() {
--- a/src/adapters/cloudflare-durable.ts
+++ b/src/adapters/cloudflare-durable.ts
@@ -2,7 +2,11 @@

 import type * as CF from "@cloudflare/workers-types";
 import type { DurableObject } from "cloudflare:workers";
-import { AdapterOptions, defineWebSocketAdapter } from "../types";
+import {
+  AdapterOptions,
+  AdapterInstance,
+  defineWebSocketAdapter,
+} from "../types";
 import { Peer } from "../peer";
 import { Message } from "../message";
 import { AdapterHookable } from "../hooks";
@@ -22,7 +26,7 @@ type CrosswsState = {
  topics?: Set<string>;
 };

-export interface CloudflareDurableAdapter {
+export interface CloudflareDurableAdapter extends AdapterInstance {
  handleUpgrade(
    req: Request | CF.Request,
    env: unknown,
@@ -59,7 +63,9 @@ export default defineWebSocketAdapter<
  CloudflareOptions
 >((opts) => {
  const hooks = new AdapterHookable(opts);
+  const peers = new Set<CloudflareDurablePeer>();
  return {
+    peers,
    handleUpgrade: async (req, env, _context) => {
      const bindingName = opts?.bindingName ?? "$DurableObject";
      const instanceName = opts?.instanceName ?? "crossws";
@@ -81,6 +87,7 @@ export default defineWebSocketAdapter<
        server as unknown as CF.WebSocket,
        request,
      );
+      peers.add(peer);
      (obj as DurableObjectPub).ctx.acceptWebSocket(server);
      hooks.callAdapterHook("cloudflare:accept", peer);
      hooks.callHook("open", peer);
@@ -98,10 +105,10 @@ export default defineWebSocketAdapter<
    },
    handleDurableClose: async (obj, ws, code, reason, wasClean) => {
      const peer = peerFromDurableEvent(obj, ws as CF.WebSocket);
+      peers.delete(peer);
      const details = { code, reason, wasClean };
      hooks.callAdapterHook("cloudflare:close", peer, details);
      hooks.callHook("close", peer, details);
-      ws.close(code, reason);
    },
  };
 });
@@ -127,6 +134,7 @@ function peerFromDurableEvent(
 }

 class CloudflareDurablePeer extends Peer<{
+  peers?: never;
  cloudflare: {
    ws: AugmentedWebSocket;
    request?: Request | CF.Request;
@@ -166,6 +174,27 @@ class CloudflareDurablePeer extends Peer<{
    this._internal.cloudflare.ws.serializeAttachment(state);
  }

+  get peers() {
+    const clients =
+      this._internal.cloudflare.context.getWebSockets() as unknown as (typeof this._internal.cloudflare.ws)[];
+    return new Set(
+      clients.map((client) => {
+        let peer = client._crosswsPeer;
+        if (!peer) {
+          peer = client._crosswsPeer = new CloudflareDurablePeer({
+            cloudflare: {
+              ws: client,
+              request: undefined,
+              env: this._internal.cloudflare.env,
+              context: this._internal.cloudflare.context,
+            },
+          });
+        }
+        return peer;
+      }),
+    );
+  }
+
  publish(topic: string, message: any): void {
    const clients = (
      this._internal.cloudflare.context.getWebSockets() as unknown as (typeof this._internal.cloudflare.ws)[]
--- a/src/adapters/cloudflare.ts
+++ b/src/adapters/cloudflare.ts
@@ -3,7 +3,11 @@
 import type * as _cf from "@cloudflare/workers-types";

 import { Peer } from "../peer";
-import { AdapterOptions, defineWebSocketAdapter } from "../types.js";
+import {
+  AdapterOptions,
+  AdapterInstance,
+  defineWebSocketAdapter,
+} from "../types.js";
 import { Message } from "../message";
 import { WSError } from "../error";
 import { AdapterHookable } from "../hooks.js";
@@ -12,7 +16,7 @@ import { toBufferLike } from "../_utils";
 declare const WebSocketPair: typeof _cf.WebSocketPair;
 declare const Response: typeof _cf.Response;

-export interface CloudflareAdapter {
+export interface CloudflareAdapter extends AdapterInstance {
  handleUpgrade(
    req: _cf.Request,
    env: unknown,
@@ -25,7 +29,9 @@ export interface CloudflareOptions extends AdapterOptions {}
 export default defineWebSocketAdapter<CloudflareAdapter, CloudflareOptions>(
  (options = {}) => {
    const hooks = new AdapterHookable(options);
+    const peers = new Set<CloudflarePeer>();
    return {
+      peers,
      handleUpgrade: async (request, env, context) => {
        const res = await hooks.callHook(
          "upgrade",
@@ -38,8 +44,10 @@ export default defineWebSocketAdapter<CloudflareAdapter, CloudflareOptions>(
        const client = pair[0];
        const server = pair[1];
        const peer = new CloudflarePeer({
+          peers,
          cloudflare: { client, server, request, env, context },
        });
+        peers.add(peer);
        server.accept();
        hooks.callAdapterHook("cloudflare:accept", peer);
        hooks.callHook("open", peer);
@@ -48,10 +56,12 @@ export default defineWebSocketAdapter<CloudflareAdapter, CloudflareOptions>(
          hooks.callHook("message", peer, new Message(event.data));
        });
        server.addEventListener("error", (event) => {
+          peers.delete(peer);
          hooks.callAdapterHook("cloudflare:error", peer, event);
          hooks.callHook("error", peer, new WSError(event.error));
        });
        server.addEventListener("close", (event) => {
+          peers.delete(peer);
          hooks.callAdapterHook("cloudflare:close", peer, event);
          hooks.callHook("close", peer, event);
        });
@@ -67,6 +77,7 @@ export default defineWebSocketAdapter<CloudflareAdapter, CloudflareOptions>(
 );

 class CloudflarePeer extends Peer<{
+  peers: Set<CloudflarePeer>;
  cloudflare: {
    client: _cf.WebSocket;
    server: _cf.WebSocket;
@@ -96,6 +107,16 @@ class CloudflarePeer extends Peer<{
    return 0;
  }

+  publish(_topic: string, _message: any): void {
+    // Not supported
+    // Throws: A hanging Promise was canceled
+    // for (const peer of this._internal.peers) {
+    //   if (peer !== this && peer._topics.has(_topic)) {
+    //     peer.publish(_topic, _message);
+    //   }
+    // }
+  }
+
  close(code?: number, reason?: string) {
    this._internal.cloudflare.client.close(code, reason);
  }
--- a/src/adapters/deno.ts
+++ b/src/adapters/deno.ts
@@ -5,11 +5,15 @@
 import { Message } from "../message.ts";
 import { WSError } from "../error.ts";
 import { Peer } from "../peer.ts";
-import { AdapterOptions, defineWebSocketAdapter } from "../types.ts";
+import {
+  AdapterOptions,
+  AdapterInstance,
+  defineWebSocketAdapter,
+} from "../types.ts";
 import { AdapterHookable } from "../hooks.ts";
 import { toBufferLike } from "../_utils.ts";

-export interface DenoAdapter {
+export interface DenoAdapter extends AdapterInstance {
  handleUpgrade(req: Request, info: ServeHandlerInfo): Promise<Response>;
 }

@@ -22,15 +26,12 @@ declare global {
 type WebSocketUpgrade = import("@deno/types").Deno.WebSocketUpgrade;
 type ServeHandlerInfo = unknown; // TODO

-type DenoWSSharedState = {
-  peers: Set<DenoPeer>;
-};
-
 export default defineWebSocketAdapter<DenoAdapter, DenoOptions>(
  (options = {}) => {
    const hooks = new AdapterHookable(options);
-    const sharedState: DenoWSSharedState = { peers: new Set() };
+    const peers = new Set<DenoPeer>();
    return {
+      peers,
      handleUpgrade: async (request, info) => {
        const res = await hooks.callHook("upgrade", request);
        if (res instanceof Response) {
@@ -41,9 +42,10 @@ export default defineWebSocketAdapter<DenoAdapter, DenoOptions>(
          headers: res?.headers,
        });
        const peer = new DenoPeer({
-          deno: { ws: upgrade.socket, request, info, sharedState },
+          peers,
+          deno: { ws: upgrade.socket, request, info },
        });
-        sharedState.peers.add(peer);
+        peers.add(peer);
        upgrade.socket.addEventListener("open", () => {
          hooks.callAdapterHook("deno:open", peer);
          hooks.callHook("open", peer);
@@ -53,12 +55,12 @@ export default defineWebSocketAdapter<DenoAdapter, DenoOptions>(
          hooks.callHook("message", peer, new Message(event.data));
        });
        upgrade.socket.addEventListener("close", () => {
-          sharedState.peers.delete(peer);
+          peers.delete(peer);
          hooks.callAdapterHook("deno:close", peer);
          hooks.callHook("close", peer, {});
        });
        upgrade.socket.addEventListener("error", (error) => {
-          sharedState.peers.delete(peer);
+          peers.delete(peer);
          hooks.callAdapterHook("deno:error", peer, error);
          hooks.callHook("error", peer, new WSError(error));
        });
@@ -69,11 +71,11 @@ export default defineWebSocketAdapter<DenoAdapter, DenoOptions>(
 );

 class DenoPeer extends Peer<{
+  peers: Set<DenoPeer>;
  deno: {
    ws: WebSocketUpgrade["socket"];
    request: Request;
    info: ServeHandlerInfo;
-    sharedState: DenoWSSharedState;
  };
 }> {
  get addr() {
@@ -98,11 +100,11 @@ class DenoPeer extends Peer<{
    return 0;
  }

-  publish(topic: string, message: any): void {
+  publish(topic: string, message: any) {
    const data = toBufferLike(message);
-    for (const peer of this._internal.deno.sharedState.peers) {
+    for (const peer of this._internal.peers) {
      if (peer !== this && peer._topics.has(topic)) {
-        peer.send(data);
+        peer._internal.deno.ws.send(data);
      }
    }
  }
--- a/src/adapters/node.ts
+++ b/src/adapters/node.ts
@@ -13,13 +13,17 @@ import type {
 import { Peer } from "../peer";
 import { Message } from "../message";
 import { WSError } from "../error";
-import { AdapterOptions, defineWebSocketAdapter } from "../types";
+import {
+  AdapterOptions,
+  AdapterInstance,
+  defineWebSocketAdapter,
+} from "../types";
 import { AdapterHookable } from "../hooks";
 import { toBufferLike } from "../_utils";

 type AugmentedReq = IncomingMessage & { _upgradeHeaders?: HeadersInit };

-export interface NodeAdapter {
+export interface NodeAdapter extends AdapterInstance {
  handleUpgrade(req: IncomingMessage, socket: Duplex, head: Buffer): void;
  closeAll: (code?: number, data?: string | Buffer) => void;
 }
@@ -32,6 +36,7 @@ export interface NodeOptions extends AdapterOptions {
 export default defineWebSocketAdapter<NodeAdapter, NodeOptions>(
  (options = {}) => {
    const hooks = new AdapterHookable(options);
+    const peers = new Set<NodePeer>();

    const wss: WebSocketServer =
      options.wss ||
@@ -41,7 +46,8 @@ export default defineWebSocketAdapter<NodeAdapter, NodeOptions>(
      }) as WebSocketServer);

    wss.on("connection", (ws, req) => {
-      const peer = new NodePeer({ node: { ws, req, server: wss } });
+      const peer = new NodePeer({ peers, node: { ws, req, server: wss } });
+      peers.add(peer);
      hooks.callHook("open", peer);

      // Managed socket-level events
@@ -53,10 +59,12 @@ export default defineWebSocketAdapter<NodeAdapter, NodeOptions>(
        hooks.callHook("message", peer, new Message(data, isBinary));
      });
      ws.on("error", (error: Error) => {
+        peers.delete(peer);
        hooks.callAdapterHook("node:error", peer, error);
        hooks.callHook("error", peer, new WSError(error));
      });
      ws.on("close", (code: number, reason: Buffer) => {
+        peers.delete(peer);
        hooks.callAdapterHook("node:close", peer, code, reason);
        hooks.callHook("close", peer, {
          code,
@@ -95,6 +103,7 @@ export default defineWebSocketAdapter<NodeAdapter, NodeOptions>(
    });

    return {
+      peers,
      handleUpgrade: async (req, socket, head) => {
        const res = await hooks.callHook("upgrade", new NodeReqProxy(req));
        if (res instanceof Response) {
@@ -163,6 +172,7 @@ async function sendResponse(socket: Duplex, res: Response) {
 }

 class NodePeer extends Peer<{
+  peers: Set<NodePeer>;
  node: {
    server: WebSocketServer;
    req: IncomingMessage;
@@ -221,9 +231,8 @@ class NodePeer extends Peer<{
      binary: isBinary,
      ...options,
    };
-    for (const client of this._internal.node.server.clients) {
-      const peer = (client as WebSocketT & { _peer?: NodePeer })._peer;
-      if (peer && peer !== this && peer._topics.has(topic)) {
+    for (const peer of this._internal.peers) {
+      if (peer !== this && peer._topics.has(topic)) {
        peer._internal.node.ws.send(data, sendOptions);
      }
    }
--- a/src/adapters/uws.ts
+++ b/src/adapters/uws.ts
@@ -10,7 +10,11 @@ import type {
 } from "uWebSockets.js";
 import { Peer } from "../peer";
 import { Message } from "../message";
-import { AdapterOptions, defineWebSocketAdapter } from "../types";
+import {
+  AdapterOptions,
+  AdapterInstance,
+  defineWebSocketAdapter,
+} from "../types";
 import { AdapterHookable } from "../hooks";
 import { toBufferLike } from "../_utils";

@@ -23,7 +27,7 @@ type UserData = {

 type WebSocketHandler = WebSocketBehavior<UserData>;

-export interface UWSAdapter {
+export interface UWSAdapter extends AdapterInstance {
  websocket: WebSocketHandler;
 }

@@ -44,11 +48,14 @@ export interface UWSOptions extends AdapterOptions {
 export default defineWebSocketAdapter<UWSAdapter, UWSOptions>(
  (options = {}) => {
    const hooks = new AdapterHookable(options);
+    const peers = new Set<UWSPeer>();
    return {
+      peers,
      websocket: {
        ...options.uws,
        close(ws, code, message) {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
+          peers.delete(peer);
          hooks.callAdapterHook("uws:close", peer, ws, code, message);
          hooks.callHook("close", peer, {
            code,
@@ -56,30 +63,31 @@ export default defineWebSocketAdapter<UWSAdapter, UWSOptions>(
          });
        },
        drain(ws) {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
          hooks.callAdapterHook("uws:drain", peer, ws);
        },
        message(ws, message, isBinary) {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
          hooks.callAdapterHook("uws:message", peer, ws, message, isBinary);
          const msg = new Message(message, isBinary);
          hooks.callHook("message", peer, msg);
        },
        open(ws) {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
+          peers.add(peer);
          hooks.callAdapterHook("uws:open", peer, ws);
          hooks.callHook("open", peer);
        },
        ping(ws, message) {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
          hooks.callAdapterHook("uws:ping", peer, ws, message);
        },
        pong(ws, message) {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
          hooks.callAdapterHook("uws:pong", peer, ws, message);
        },
        subscription(ws, topic, newCount, oldCount) {
-          const peer = getPeer(ws);
+          const peer = getPeer(ws, peers);
          hooks.callAdapterHook(
            "uws:subscription",
            peer,
@@ -146,14 +154,14 @@ class UWSReqProxy {
  private _rawHeaders: [string, string][] = [];
  url: string;

-  constructor(private _req: HttpRequest) {
+  constructor(_req: HttpRequest) {
    // We need to precompute values since uws doesn't provide them after handler.

    // Headers
    let host = "localhost";
    let proto = "http";
    // eslint-disable-next-line unicorn/no-array-for-each
-    this._req.forEach((key, value) => {
+    _req.forEach((key, value) => {
      if (key === "host") {
        host = value;
      } else if (key === "x-forwarded-proto" && value === "https") {
@@ -176,17 +184,18 @@ class UWSReqProxy {
  }
 }

-function getPeer(ws: WebSocket<UserData>) {
+function getPeer(ws: WebSocket<UserData>, peers: Set<UWSPeer>): UWSPeer {
  const userData = ws.getUserData();
  if (userData._peer) {
-    return userData._peer as Peer;
+    return userData._peer as UWSPeer;
  }
-  const peer = new UWSPeer({ uws: { ws, userData } });
+  const peer = new UWSPeer({ peers, uws: { ws, userData } });
  userData._peer = peer;
  return peer;
 }

 class UWSPeer extends Peer<{
+  peers: Set<UWSPeer>;
  uws: {
    ws: WebSocket<UserData>;
    userData: UserData;
--- a/src/peer.ts
+++ b/src/peer.ts
@@ -8,17 +8,21 @@ const ReadyStateMap = {
  3: "closed",
 } as const;

-export abstract class Peer<AdapterContext = any> {
-  protected _internal: AdapterContext;
+export interface AdapterInternal {
+  peers?: Set<Peer>;
+}
+
+export abstract class Peer<Internal extends AdapterInternal = AdapterInternal> {
+  protected _internal: Internal;
  protected _topics: Set<string>;

  private static _idCounter = 0;
  private _id: string;

-  constructor(_internalCtx: AdapterContext) {
+  constructor(internal: Internal) {
    this._id = ++Peer._idCounter + "";
    this._topics = new Set();
-    this._internal = _internalCtx;
+    this._internal = internal;
  }

  get id(): string {
@@ -41,11 +45,17 @@ export abstract class Peer<AdapterContext = any> {
    return -1;
  }

+  get peers(): Set<Peer> {
+    return this._internal.peers || new Set();
+  }
+
  abstract send(message: any, options?: { compress?: boolean }): number;

-  publish(topic: string, message: any, options?: { compress?: boolean }) {
-    // noop
-  }
+  abstract publish(
+    topic: string,
+    message: any,
+    options?: { compress?: boolean },
+  ): void;

  subscribe(topic: string) {
    this._topics.add(topic);
--- a/src/types.ts
+++ b/src/types.ts
@@ -4,7 +4,9 @@ import type { Peer } from "./peer.ts";

 // --- Adapter ---

-export interface CrossWSAdapter {}
+export interface AdapterInstance {
+  readonly peers: Set<Peer>;
+}

 export interface AdapterOptions {
  resolve?: ResolveHooks;
@@ -13,12 +15,12 @@ export interface AdapterOptions {
 }

 export type Adapter<
-  AdapterT extends CrossWSAdapter = CrossWSAdapter,
+  AdapterT extends AdapterInstance = AdapterInstance,
  Options extends AdapterOptions = AdapterOptions,
 > = (options?: Options) => AdapterT;

 export function defineWebSocketAdapter<
-  AdapterT extends CrossWSAdapter = CrossWSAdapter,
+  AdapterT extends AdapterInstance = AdapterInstance,
  Options extends AdapterOptions = AdapterOptions,
 >(factory: Adapter<AdapterT, Options>) {
  return factory;
--- a/test/_utils.ts
+++ b/test/_utils.ts
@@ -8,15 +8,24 @@ import { wsTests } from "./tests";

 const fixtureDir = fileURLToPath(new URL("fixture", import.meta.url));

+const websockets = new Set<WebSocket>();
+afterEach(() => {
+  for (const ws of websockets) {
+    ws.close();
+  }
+  websockets.clear();
+});
+
 export function wsConnect(
  url: string,
  opts?: { skip?: number; headers?: OutgoingHttpHeaders },
 ) {
  const ws = new WebSocket(url, { headers: opts?.headers });
+  websockets.add(ws);

  const upgradeHeaders: Record<string, string> = Object.create(null);

-  const send = async (data: any) => {
+  const send = async (data: any): Promise<any> => {
    ws.send(
      typeof data === "string" ? data : JSON.stringify({ message: data }),
    );
@@ -55,11 +64,6 @@ export function wsConnect(
    }
  });

-  afterEach(() => {
-    ws.removeAllListeners();
-    ws.close();
-  });
-
  const res = {
    ws,
    send,
--- a/test/adapters/node.test.ts
+++ b/test/adapters/node.test.ts
@@ -12,7 +12,14 @@ describe("node", () => {

  beforeAll(async () => {
    ws = createDemo(nodeAdapter);
-    server = createServer((_req, res) => {
+    server = createServer((req, res) => {
+      if (req.url === "/peers") {
+        return res.end(
+          JSON.stringify({
+            peers: [...ws.peers].map((p) => p.id),
+          }),
+        );
+      }
      res.end("ok");
    });
    server.on("upgrade", ws.handleUpgrade);
--- a/test/adapters/uws.test.ts
+++ b/test/adapters/uws.test.ts
@@ -19,14 +19,19 @@ describe("uws", () => {
      res.onAborted(() => {
        aborted = true;
      });
-      const html = "OK";
+
+      let resBody = "OK";
+      const url = req.getUrl();
+      if (url === "/peers") {
+        resBody = JSON.stringify({ peers: [...ws.peers].map((p) => p.id) });
+      }
+
      if (aborted) {
        return;
      }
      res.cork(() => {
        res.writeStatus("200 OK");
-        res.writeHeader("Content-Type", "text/html");
-        res.end(html);
+        res.end(resBody);
      });
    });

--- a/test/fixture/_shared.ts
+++ b/test/fixture/_shared.ts
@@ -1,4 +1,4 @@
-import { ResolveHooks, Adapter, defineHooks } from "../../src/index.ts";
+import { Adapter, AdapterInstance, defineHooks } from "../../src/index.ts";

 export const getIndexHTML = () =>
  import("./_index.html.ts").then((r) => r.default);
@@ -33,6 +33,12 @@ export function createDemo<T extends Adapter<any, any>>(
          });
          break;
        }
+        case "peers": {
+          peer.send({
+            peers: [...peer.peers].map((p) => p.id),
+          });
+          break;
+        }
        default: {
          peer.send(msgText);
          peer.publish("chat", msgText);
@@ -61,3 +67,17 @@ export function createDemo<T extends Adapter<any, any>>(
    hooks,
  });
 }
+
+export function handleDemoRoutes(
+  ws: AdapterInstance,
+  request: Request,
+): Response | undefined {
+  const url = new URL(request.url);
+  if (url.pathname === "/peers") {
+    return new Response(
+      JSON.stringify({
+        peers: [...ws.peers].map((p) => p.id),
+      }),
+    );
+  }
+}
--- a/test/fixture/bun.ts
+++ b/test/fixture/bun.ts
@@ -1,7 +1,7 @@
 // You can run this demo using `bun --bun ./bun.ts` or `npm run play:bun` in repo

 import bunAdapter from "../../src/adapters/bun";
-import { createDemo, getIndexHTML } from "./_shared";
+import { createDemo, getIndexHTML, handleDemoRoutes } from "./_shared";

 const ws = createDemo(bunAdapter);

@@ -10,6 +10,10 @@ Bun.serve({
  hostname: "localhost",
  websocket: ws.websocket,
  async fetch(request, server) {
+    const response = handleDemoRoutes(ws, request);
+    if (response) {
+      return response;
+    }
    if (request.headers.get("upgrade") === "websocket") {
      return ws.handleUpgrade(request, server);
    }
--- a/test/fixture/cloudflare-durable.ts
+++ b/test/fixture/cloudflare-durable.ts
@@ -1,7 +1,7 @@
 // You can run this demo using `npm run play:cf-durable` in repo
 import { DurableObject } from "cloudflare:workers";
 import cloudflareAdapter from "../../src/adapters/cloudflare-durable.ts";
-import { createDemo, getIndexHTML } from "./_shared.ts";
+import { createDemo, getIndexHTML, handleDemoRoutes } from "./_shared.ts";

 const ws = createDemo(cloudflareAdapter);

@@ -11,6 +11,11 @@ export default {
    env: Record<string, any>,
    context: ExecutionContext,
  ): Promise<Response> {
+    const response = handleDemoRoutes(ws, request);
+    if (response) {
+      return response;
+    }
+
    if (request.headers.get("upgrade") === "websocket") {
      return ws.handleUpgrade(request, env, context);
    }
--- a/test/fixture/cloudflare.ts
+++ b/test/fixture/cloudflare.ts
@@ -1,7 +1,7 @@
 // You can run this demo using `npm run play:cf` in repo
-import type { Request, ExecutionContext } from "@cloudflare/workers-types";
+import type { ExecutionContext } from "@cloudflare/workers-types";
 import cloudflareAdapter from "../../src/adapters/cloudflare";
-import { createDemo, getIndexHTML } from "./_shared.ts";
+import { createDemo, getIndexHTML, handleDemoRoutes } from "./_shared.ts";

 const ws = createDemo(cloudflareAdapter);

@@ -11,8 +11,13 @@ export default {
    env: Record<string, any>,
    context: ExecutionContext,
  ) {
+    const response = handleDemoRoutes(ws, request);
+    if (response) {
+      return response;
+    }
+
    if (request.headers.get("upgrade") === "websocket") {
-      return ws.handleUpgrade(request, env, context);
+      return ws.handleUpgrade(request as any, env, context);
    }

    return new Response(await getIndexHTML(), {
--- a/test/fixture/deno.ts
+++ b/test/fixture/deno.ts
@@ -5,15 +5,20 @@ import denoAdapter from "../../src/adapters/deno.ts";
 // @ts-ignore
 import type * as _Deno from "../types/lib.deno.d.ts";

-import { createDemo, getIndexHTML } from "./_shared.ts";
+import { createDemo, getIndexHTML, handleDemoRoutes } from "./_shared.ts";

 const ws = createDemo(denoAdapter);

 const port = Number.parseInt(Deno.env.get("PORT") || "") || 3001;

-Deno.serve({ hostname: "localhost", port }, async (req, info) => {
-  if (req.headers.get("upgrade") === "websocket") {
-    return ws.handleUpgrade(req, info);
+Deno.serve({ hostname: "localhost", port }, async (request, info) => {
+  const response = handleDemoRoutes(ws, request);
+  if (response) {
+    return response;
+  }
+
+  if (request.headers.get("upgrade") === "websocket") {
+    return ws.handleUpgrade(request, info);
  }
  return new Response(await getIndexHTML(), {
    headers: { "Content-Type": "text/html" },
--- a/test/tests.ts
+++ b/test/tests.ts
@@ -88,4 +88,26 @@ export function wsTests(
      },
    });
  });
+
+  test("get peers from adapter", async () => {
+    await wsConnect(getURL());
+    await wsConnect(getURL());
+    const response = await fetch(getURL().replace("ws", "http") + "peers");
+    const { peers } = (await response.json()) as any;
+    expect(peers.length).toBe(2);
+  });
+
+  test("get peers from peer", async () => {
+    const ws1 = await wsConnect(getURL(), { skip: 1 });
+    const ws2 = await wsConnect(getURL(), { skip: 1 });
+    if (opts.pubsub !== false) {
+      ws1.skip(); // join message for ws2
+    }
+    await ws1.send("peers");
+    await ws2.send("peers");
+    const { peers: peers1 } = await ws1.next();
+    const { peers: peers2 } = await ws2.next();
+    expect(peers1.length).toBe(2);
+    expect(peers1).toMatchObject(peers2);
+  });
 }