From 5acaaace7fefd0f587ef7a2857492b68b01c2a2c Mon Sep 17 00:00:00 2001
From: katereznykova <kreznykova@cloudflare.com>
Date: Mon, 15 Dec 2025 10:07:44 +0000
Subject: [PATCH 1/3] update ws example

---
 .../sandbox/guides/websocket-connections.mdx  | 49 +++++++++++++------
 1 file changed, 35 insertions(+), 14 deletions(-)

diff --git a/src/content/docs/sandbox/guides/websocket-connections.mdx b/src/content/docs/sandbox/guides/websocket-connections.mdx
index 090152e2e33..8b3d984d98c 100644
--- a/src/content/docs/sandbox/guides/websocket-connections.mdx
+++ b/src/content/docs/sandbox/guides/websocket-connections.mdx
@@ -108,7 +108,7 @@ Get a public URL for your WebSocket server:
 ```ts
 import { getSandbox, proxyToSandbox } from '@cloudflare/sandbox';
 
-export { Sandbox } from '@cloudflare/sandbox';
+export { Sandbox } from "@cloudflare/sandbox";
 
 export default {
   async fetch(request: Request, env: Env): Promise<Response> {
@@ -129,6 +129,7 @@ export default {
     }
 
     return new Response('Not found', { status: 404 });
+
 }
 };
 
@@ -156,25 +157,45 @@ Your Worker can connect to a WebSocket service to get real-time data, even when
 ```ts
 import { getSandbox } from '@cloudflare/sandbox';
 
-export { Sandbox } from '@cloudflare/sandbox';
+export { Sandbox } from "@cloudflare/sandbox";
+
+const initialized = new Set<string>();
 
 export default {
   async fetch(request: Request, env: Env): Promise<Response> {
-    const sandbox = getSandbox(env.Sandbox, 'data-processor');
 
-    // Incoming HTTP request needs real-time data from sandbox
-    const wsRequest = new Request('ws://internal', {
-      headers: {
-        'Upgrade': 'websocket',
-        'Connection': 'Upgrade'
-      }
-    });
+     // Get or create a sandbox instance
+    const sandbox = getSandbox(env.Sandbox, 'data-processor');
 
-    // Connect to WebSocket service in sandbox
-    const wsResponse = await sandbox.wsConnect(wsRequest, 8080);
 
-    // Process WebSocket stream and return HTTP response
-    // (Implementation depends on your needs)
+    // Check for WebSocket upgrade
+    const upgrade = request.headers.get('Upgrade')?.toLowerCase();
+
+    if (upgrade === 'websocket') {
+      // Initialize server on first connection
+      if (!initialized.has('websocket-app')) {
+        await sandbox.writeFile(
+          '/workspace/server.js',
+          `Bun.serve({
+            port: 8080,
+            fetch(req, server) {
+              server.upgrade(req);
+            },
+            websocket: {
+              message(ws, msg) {
+                ws.send(\`Echo: \${msg}\`);
+              }
+            }
+          });`
+        );
+        await sandbox.startProcess(
+          'bun /workspace/server.js'
+        );
+        initialized.add('websocket-app');
+      }
+      // Connect to WebSocket server
+      return await sandbox.wsConnect(request, 8080);
+    }
 
     return new Response('Processed real-time data');
 

From 6b9643ff762b12ca61379003c03369b29b15ed0e Mon Sep 17 00:00:00 2001
From: whoiskatrin <kreznykova@cloudflare.com>
Date: Mon, 15 Dec 2025 10:12:31 +0000
Subject: [PATCH 2/3] Fix export statement quotes in websocket connections
 guide

---
 src/content/docs/sandbox/guides/websocket-connections.mdx | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/content/docs/sandbox/guides/websocket-connections.mdx b/src/content/docs/sandbox/guides/websocket-connections.mdx
index 8b3d984d98c..483109ec073 100644
--- a/src/content/docs/sandbox/guides/websocket-connections.mdx
+++ b/src/content/docs/sandbox/guides/websocket-connections.mdx
@@ -108,7 +108,7 @@ Get a public URL for your WebSocket server:
 ```ts
 import { getSandbox, proxyToSandbox } from '@cloudflare/sandbox';
 
-export { Sandbox } from "@cloudflare/sandbox";
+export { Sandbox } from '@cloudflare/sandbox';
 
 export default {
   async fetch(request: Request, env: Env): Promise<Response> {
@@ -157,7 +157,7 @@ Your Worker can connect to a WebSocket service to get real-time data, even when
 ```ts
 import { getSandbox } from '@cloudflare/sandbox';
 
-export { Sandbox } from "@cloudflare/sandbox";
+export { Sandbox } from '@cloudflare/sandbox';
 
 const initialized = new Set<string>();
 

From d4366d81292f7b0d2a0de6aea5aea6859b61c23c Mon Sep 17 00:00:00 2001
From: whoiskatrin <kreznykova@cloudflare.com>
Date: Mon, 15 Dec 2025 10:21:48 +0000
Subject: [PATCH 3/3] Refactor WebSocket initialization logic

---
 src/content/docs/sandbox/guides/websocket-connections.mdx | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/content/docs/sandbox/guides/websocket-connections.mdx b/src/content/docs/sandbox/guides/websocket-connections.mdx
index 483109ec073..2a9eaa2c271 100644
--- a/src/content/docs/sandbox/guides/websocket-connections.mdx
+++ b/src/content/docs/sandbox/guides/websocket-connections.mdx
@@ -159,7 +159,7 @@ import { getSandbox } from '@cloudflare/sandbox';
 
 export { Sandbox } from '@cloudflare/sandbox';
 
-const initialized = new Set<string>();
+let initialized = false;
 
 export default {
   async fetch(request: Request, env: Env): Promise<Response> {
@@ -173,7 +173,7 @@ export default {
 
     if (upgrade === 'websocket') {
       // Initialize server on first connection
-      if (!initialized.has('websocket-app')) {
+      if (!initialized) {
         await sandbox.writeFile(
           '/workspace/server.js',
           `Bun.serve({
@@ -191,7 +191,7 @@ export default {
         await sandbox.startProcess(
           'bun /workspace/server.js'
         );
-        initialized.add('websocket-app');
+        initialized = true;
       }
       // Connect to WebSocket server
       return await sandbox.wsConnect(request, 8080);