azure-web-pubsub-ts

Author's original introduction

Build real-time messaging applications using Azure Web PubSub SDKs for JavaScript (@azure/web-pubsub, @azure/web-pubsub-client). Use when implementing WebSocket-based real-time features, pub/sub messaging, group chat, or live notifications.

SkillPi interpretation

Tasks

azure-web-pubsub-ts

Audience

Use the scope in the original author introduction.

Inputs and outputs

See the complete source; users must confirm cloud data transfers.

Software, accounts and paid services

This azure-web-pubsub-ts package contains Microsoft Azure SDK documentation and examples, not a runtime-verified installer. Check SDK names/versions, tenant/subscription and actual endpoints; grant only task-specific least privilege. Never put administrator credentials or real secrets in samples, logs or commits. Connected cloud services may receive selected text, documents, audio, messages, logs or other input and incur charges; confirm scope, redaction and costs first. Ask the user to confirm each resource creation/update/deletion, key/access change or outbound message and test with disposable resources before production. Replace and verify placeholder endpoints and samples. SkillPi checked pinned source, complete attachments and static/antivirus evidence only; it did not run the SDK, verify service compatibility or authorize cloud access.

Limits and differences

Original author introduction preserved; Chinese is a corresponding translation. Examples were not run by SkillPi; versions, compatibility and outcomes are author claims.

Testing

Not tested

Security rating and access scope

caution · Static evidence review; not a runtime safety guarantee.

This azure-web-pubsub-ts package contains Microsoft Azure SDK documentation and examples, not a runtime-verified installer. Check SDK names/versions, tenant/subscription and actual endpoints; grant only task-specific least privilege. Never put administrator credentials or real secrets in samples, logs or commits. Connected cloud services may receive selected text, documents, audio, messages, logs or other input and incur charges; confirm scope, redaction and costs first. Ask the user to confirm each resource creation/update/deletion, key/access change or outbound message and test with disposable resources before production. Replace and verify placeholder endpoints and samples. SkillPi checked pinned source, complete attachments and static/antivirus evidence only; it did not run the SDK, verify service compatibility or authorize cloud access.

Before use, confirm and authorize actual file access, external services and network destinations in your host. This review grants no runtime permissions.

Original SKILL.md

---
name: azure-web-pubsub-ts
description: Build real-time messaging applications using Azure Web PubSub SDKs for JavaScript (@azure/web-pubsub, @azure/web-pubsub-client). Use when implementing WebSocket-based real-time features, pub/sub messaging, group chat, or live notifications.
license: MIT
metadata:
  author: Microsoft
  version: "1.0.0"
  package: '@azure/web-pubsub, @azure/web-pubsub-client'
---

# Azure Web PubSub SDKs for TypeScript

Real-time messaging with WebSocket connections and pub/sub patterns.

## Installation

```bash
# Server-side management
npm install @azure/web-pubsub @azure/identity

# Client-side real-time messaging
npm install @azure/web-pubsub-client

# Express middleware for event handlers
npm install @azure/web-pubsub-express
```

## Environment Variables

```bash
WEBPUBSUB_CONNECTION_STRING=Endpoint=https://<resource>.webpubsub.azure.com;AccessKey=<key>;Version=1.0;
WEBPUBSUB_ENDPOINT=https://<resource>.webpubsub.azure.com
AZURE_TOKEN_CREDENTIALS=prod # Required only if DefaultAzureCredential is used in production
```

## Server-Side: WebPubSubServiceClient

### Authentication

```typescript
import { WebPubSubServiceClient, AzureKeyCredential } from "@azure/web-pubsub";
import { DefaultAzureCredential, ManagedIdentityCredential } from "@azure/identity";

// Local dev: DefaultAzureCredential. Production: set AZURE_TOKEN_CREDENTIALS=prod or AZURE_TOKEN_CREDENTIALS=<specific_credential>
const credential = new DefaultAzureCredential({requiredEnvVars: ["AZURE_TOKEN_CREDENTIALS"]});
// Or use a specific credential directly in production:
// See https://learn.microsoft.com/javascript/api/overview/azure/identity-readme?view=azure-node-latest#credential-classes
// const credential = new ManagedIdentityCredential();

// Connection string
const client = new WebPubSubServiceClient(
  process.env.WEBPUBSUB_CONNECTION_STRING!,
  "chat"  // hub name
);

// Microsoft Entra Token Credential (recommended)
const client2 = new WebPubSubServiceClient(
  process.env.WEBPUBSUB_ENDPOINT!,
  credential,
  "chat"
);

// AzureKeyCredential
const client3 = new WebPubSubServiceClient(
  process.env.WEBPUBSUB_ENDPOINT!,
  new AzureKeyCredential("<access-key>"),
  "chat"
);
```

### Generate Client Access Token

```typescript
// Basic token
const token = await client.getClientAccessToken();
console.log(token.url);  // wss://...?access_token=...

// Token with user ID
const userToken = await client.getClientAccessToken({
  userId: "user123",
});

// Token with permissions
const permToken = await client.getClientAccessToken({
  userId: "user123",
  roles: [
    "webpubsub.joinLeaveGroup",
    "webpubsub.sendToGroup",
    "webpubsub.sendToGroup.chat-room",  // specific group
  ],
  groups: ["chat-room"],  // auto-join on connect
  expirationTimeInMinutes: 60,
});
```

### Send Messages

```typescript
// Broadcast to all connections in hub
await client.sendToAll({ message: "Hello everyone!" });
await client.sendToAll("Plain text", { contentType: "text/plain" });

// Send to specific user (all their connections)
await client.sendToUser("user123", { message: "Hello!" });

// Send to specific connection
await client.sendToConnection("connectionId", { data: "Direct message" });

// Send with filter (OData syntax)
await client.sendToAll({ message: "Filtered" }, {
  filter: "userId ne 'admin'",
});
```

### Group Management

```typescript
const group = client.group("chat-room");

// Add user/connection to group
await group.addUser("user123");
await group.addConnection("connectionId");

// Remove from group
await group.removeUser("user123");

// Send to group
await group.sendToAll({ message: "Group message" });

// Close all connections in group
await group.closeAllConnections({ reason: "Maintenance" });
```

### Connection Management

```typescript
// Check existence
const userExists = await client.userExists("user123");
const connExists = await client.connectionExists("connectionId");

// Close connections
await client.closeConnection("connectionId", { reason: "Kicked" });
await client.closeUserConnections("user123");
await client.closeAllConnections();

// Permissions
await client.grantPermission("connectionId", "sendToGroup", { targetName: "chat" });
await client.revokePermission("connectionId", "sendToGroup", { targetName: "chat" });
```

## Client-Side: WebPubSubClient

### Connect

```typescript
import { WebPubSubClient } from "@azure/web-pubsub-client";

// Direct URL
const client = new WebPubSubClient("<client-access-url>");

// Dynamic URL from negotiate endpoint
const client2 = new WebPubSubClient({
  getClientAccessUrl: async () => {
    const response = await fetch("/negotiate");
    const { url } = await response.json();
    return url;
  },
});

// Register handlers BEFORE starting
client.on("connected", (e) => {
  console.log(`Connected: ${e.connectionId}`);
});

client.on("group-message", (e) => {
  console.log(`${e.message.group}: ${e.message.data}`);
});

await client.start();
```

### Send Messages

```typescript
// Join group first
await client.joinGroup("chat-room");

// Send to group
await client.sendToGroup("chat-room", "Hello!", "text");
await client.sendToGroup("chat-room", { type: "message", content: "Hi" }, "json");

// Send options
await client.sendToGroup("chat-room", "Hello", "text", {
  noEcho: true,        // Don't echo back to sender
  fireAndForget: true, // Don't wait for ack
});

// Send event to server
await client.sendEvent("userAction", { action: "typing" }, "json");
```

### Event Handlers

```typescript
// Connection lifecycle
client.on("connected", (e) => {
  console.log(`Connected: ${e.connectionId}, User: ${e.userId}`);
});

client.on("disconnected", (e) => {
  console.log(`Disconnected: ${e.message}`);
});

client.on("stopped", () => {
  console.log("Client stopped");
});

// Messages
client.on("group-message", (e) => {
  console.log(`[${e.message.group}] ${e.message.fromUserId}: ${e.message.data}`);
});

client.on("server-message", (e) => {
  console.log(`Server: ${e.message.data}`);
});

// Rejoin failure
client.on("rejoin-group-failed", (e) => {
  console.log(`Failed to rejoin ${e.group}: ${e.error}`);
});
```

## Express Event Handler

```typescript
import express from "express";
import { WebPubSubEventHandler } from "@azure/web-pubsub-express";

const app = express();

const handler = new WebPubSubEventHandler("chat", {
  path: "/api/webpubsub/hubs/chat/",
  
  // Blocking: approve/reject connection
  handleConnect: (req, res) => {
    if (!req.claims?.sub) {
      res.fail(401, "Authentication required");
      return;
    }
    res.success({
      userId: req.claims.sub[0],
      groups: ["general"],
      roles: ["webpubsub.sendToGroup"],
    });
  },
  
  // Blocking: handle custom events
  handleUserEvent: (req, res) => {
    console.log(`Event from ${req.context.userId}:`, req.data);
    res.success(`Received: ${req.data}`, "text");
  },
  
  // Non-blocking
  onConnected: (req) => {
    console.log(`Client connected: ${req.context.connectionId}`);
  },
  
  onDisconnected: (req) => {
    console.log(`Client disconnected: ${req.context.connectionId}`);
  },
});

app.use(handler.getMiddleware());

// Negotiate endpoint
app.get("/negotiate", async (req, res) => {
  const token = await serviceClient.getClientAccessToken({
    userId: req.user?.id,
  });
  res.json({ url: token.url });
});

app.listen(8080);
```

## Key Types

```typescript
// Server
import {
  WebPubSubServiceClient,
  WebPubSubGroup,
  GenerateClientTokenOptions,
  HubSendToAllOptions,
} from "@azure/web-pubsub";

// Client
import {
  WebPubSubClient,
  WebPubSubClientOptions,
  OnConnectedArgs,
  OnGroupDataMessageArgs,
} from "@azure/web-pubsub-client";

// Express
import {
  WebPubSubEventHandler,
  ConnectRequest,
  UserEventRequest,
  ConnectResponseHandler,
} from "@azure/web-pubsub-express";
```

## Best Practices

1. **Use Microsoft Entra Token Credential** - Use `DefaultAzureCredential` for local development; use `ManagedIdentityCredential` or `WorkloadIdentityCredential` for production
2. **Register handlers before start** - Don't miss initial events
3. **Use groups for channels** - Organize messages by topic/room
4. **Handle reconnection** - Client auto-reconnects by default
5. **Validate in handleConnect** - Reject unauthorized connections early
6. **Use noEcho** - Prevent message echo back to sender when needed

Copyright and license notice

    MIT License

    Copyright (c) Microsoft Corporation.

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE