feat: websocket support

.prettierignore

@@ -2,3 +2,4 @@ dist
 lib
 .nuxt
 .output
+docs/**/*.md

docs/.config/docs.yaml

@@ -7,7 +7,7 @@ description:
 github: unjs/h3
 themeColor: amber
 url: https://h3.unjs.io
-# automd: true # HMR seems unstable
+automd: true
 redirects: {}
 landing:
   heroLinks:

docs/1.guide/6.websocket.md

@@ -0,0 +1,115 @@
+---
+icon: cib:socket-io
+---
+
+# WebSockets
+
+> H3 has built-in support for cross platform WebSocket and SSE.
+
+H3 natively supports runtime agnostic [WebSocket](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket) API using [CrossWS](https://crossws.unjs.io/).
+
+::tip
+You can define WebSocket handlers in your exisiting [Event Handlers](/guide/event-handler) to define multiple websocket handlers, dynamically matched with your same route defenitions!
+::
+
+:read-more{title="WebSocket in MDN" to="https://developer.mozilla.org/en-US/docs/Web/API/WebSocket"}
+
+:read-more{title="CrossWS" to="https://crossws.unjs.io/"}
+
+> [!IMPORTANT]
+> WebSockets support is currently experimental and available in [nightly channel](/guide/nightly).
+
+## Usage
+
+### Example
+
+> [!TIP]
+> Yuu can use `npx listhen --ws -w websocket.ts` to run this example
+
+<!-- automd:file code src="../../examples/websocket.ts" -->
+
+```ts [websocket.ts]
+import { createApp, defineEventHandler, defineWebSocketHandler } from "h3";
+
+export const app = createApp();
+
+app.use(
+  defineEventHandler(() =>
+    fetch(
+      "https://raw.githubusercontent.com/unjs/crossws/main/examples/h3/public/index.html",
+    ).then((r) => r.text()),
+  ),
+);
+
+app.use(
+  "/_ws",
+  defineWebSocketHandler({
+    open(peer) {
+      console.log("[ws] open", peer);
+    },
+
+    message(peer, message) {
+      console.log("[ws] message", peer, message);
+      if (message.text().includes("ping")) {
+        peer.send("pong");
+      }
+    },
+
+    close(peer, event) {
+      console.log("[ws] close", peer, event);
+    },
+
+    error(peer, error) {
+      console.log("[ws] error", peer, error);
+    },
+  }),
+);
+
+```
+
+<!-- /automd -->
+
+## Server Sent Events (SSE)
+
+As an alternative to WebSockets, you can use [Server-sent events](https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events).
+
+H3 has a built-in API to create server-sent events using `createEventStream(event)` utility.
+
+> [!IMPORTANT]
+> SSE support is currently experimental and available in [nightly channel](/guide/nightly).
+
+### Example
+
+<!-- automd:file code src="../../examples/server-sent-events.ts" -->
+
+```ts [server-sent-events.ts]
+import { createApp, createRouter, eventHandler, createEventStream } from "h3";
+
+export const app = createApp();
+
+const router = createRouter();
+app.use(router);
+
+router.get(
+  "/",
+  eventHandler((event) => {
+    const eventStream = createEventStream(event);
+
+    // Send a message every second
+    const interval = setInterval(async () => {
+      await eventStream.push("Hello world");
+    }, 1000);
+
+    // cleanup the interval and close the stream when the connection is terminated
+    eventStream.onClosed(async () => {
+      clearInterval(interval);
+      await eventStream.close();
+    });
+
+    return eventStream.send();
+  }),
+);
+
+```
+
+<!-- /automd -->

docs/3.adapters/1.node.md

@@ -45,3 +45,18 @@ Run this command to run your servers:
 ```sh
 npx --yes listhen ./app.ts
 ```
+
+## WebSocket support
+
+:read-more{to="https://crossws.unjs.io/adapters/node"}
+
+> [!TIP]
+> When using listhen method, websocket is supported out of the box!
+
+```ts
+import wsAdapter from "crossws/adapters/node";
+
+const { handleUpgrade } = wsAdapter(app.websocket);
+
+server.on("upgrade", handleUpgrade);
+```

docs/3.adapters/bun.md

@@ -40,3 +40,27 @@ Now, your can run Bun server:
 ```bash
 bun --bun ./server.mjs
 ```
+
+## WebSocket support
+
+:read-more{to="https://crossws.unjs.io/adapters/bun"}
+
+```ts
+import wsAdapter from "crossws/adapters/cloudflare";
+
+const { websocket, handleUpgrade } = wsAdapter(app.websocket);
+
+const handler = toWebHandler(app)
+
+const server = Bun.serve({
+  port: 3000,
+  websocket,
+  fetch(req, server) {
+    if (await handleUpgrade(req, server)) {
+      return;
+    }
+    return handler(req)
+  }
+});
+```
+

docs/3.adapters/cloudflare.md

@@ -57,6 +57,27 @@ To deploy, use `wrangler deploy`:
 npx wrangler deploy
 ```
 
+## WebSocket support
+
+:read-more{to="https://crossws.unjs.io/adapters/cloudflare"}
+
+```ts
+import wsAdapter from "crossws/adapters/cloudflare";
+
+const { handleUpgrade } = wsAdapter(app.websocket);
+
+export default {
+  async fetch(request, env, ctx) {
+    if (request.headers.get("upgrade") === "websocket") {
+      return handleUpgrade(request, env, context);
+    }
+    return handler(request, {
+      cloudflare: { env, ctx },
+    });
+  },
+};
+```
+
 ---
 
 ::read-more

docs/3.adapters/deno.md

@@ -51,6 +51,25 @@ To deploy, use `deployctl deploy`:
 deployctl deploy --prod --exclude=node_modules --import-map=./import_map.json ./deno.mjs
 ```
 
+## WebSocket support
+
+:read-more{to="https://crossws.unjs.io/adapters/deno"}
+
+```ts
+import wsAdapter from "crossws/adapters/deno";
+
+const handler = toWebHandler(app)
+
+const { handleUpgrade } = wsAdapter(app.websocket);
+
+Deno.serve(request => {
+  if (request.headers.get("upgrade") === "websocket") {
+    return handleUpgrade(request);
+  }
+  return handler(request)
+})
+```
+
 ---
 
 ::read-more

examples/websocket.ts

@@ -0,0 +1,35 @@
+import { createApp, defineEventHandler, defineWebSocketHandler } from "h3";
+
+export const app = createApp();
+
+app.use(
+  defineEventHandler(() =>
+    fetch(
+      "https://raw.githubusercontent.com/unjs/crossws/main/examples/h3/public/index.html",
+    ).then((r) => r.text()),
+  ),
+);
+
+app.use(
+  "/_ws",
+  defineWebSocketHandler({
+    open(peer) {
+      console.log("[ws] open", peer);
+    },
+
+    message(peer, message) {
+      console.log("[ws] message", peer, message);
+      if (message.text().includes("ping")) {
+        peer.send("pong");
+      }
+    },
+
+    close(peer, event) {
+      console.log("[ws] close", peer, event);
+    },
+
+    error(peer, error) {
+      console.log("[ws] error", peer, error);
+    },
+  }),
+);

package.json

@@ -32,6 +32,7 @@
   },
   "dependencies": {
     "cookie-es": "^1.0.0",
+    "crossws": "^0.2.0",
     "defu": "^6.1.4",
     "destr": "^2.0.3",
     "iron-webcrypto": "^1.0.0",
@@ -56,7 +57,7 @@
     "express": "^4.18.2",
     "get-port": "^7.0.0",
     "jiti": "^1.21.0",
-    "listhen": "^1.6.0",
+    "listhen": "^1.7.2",
     "node-fetch-native": "^1.6.2",
     "prettier": "^3.2.5",
     "react": "^18.2.0",