身份验证与授权
在握手期间集成身份验证机制(例如 JWT),并管理 WebSocket 消息的用户权限。
身份验证与授权 是 CoddyKit 上的免费 WebSockets & Realtime Systems Programming 课时。 这是第 2 节课,共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 WebSockets & Realtime Systems Programming 学习路径的一部分,你的进度在网页和 CoddyKit 应用中同步。 WebSockets & Realtime Systems Programming 课程共包含 4 节课。
本课时的部分内容尚未翻译,以英文显示。
Securing WebSocket Interactions
WebSockets enable powerful real-time communication. But just like any web interaction, we need to know who is connecting and what they are allowed to do.
This is where authentication and authorization come in. They are crucial for building secure and reliable applications.
Auth Challenges for WebSockets
Unlike traditional HTTP requests, which are stateless and often carry authentication headers with each request, WebSockets establish a persistent, stateful connection.
This means we authenticate once during the initial connection handshake, and then the server must remember the client's identity for the duration of the connection.
Authentication During Handshake
The perfect moment to authenticate a client is during the WebSocket handshake. This is the initial HTTP request that upgrades to a WebSocket connection.
- The client sends an HTTP GET request with a
Upgrade: websocketheader. - The server can inspect this request for authentication credentials before deciding to upgrade.
- If credentials are valid, the connection is established; otherwise, it's rejected.
Passing Credentials: Query Params
One way to pass credentials is via query parameters in the WebSocket URL. For example: ws://server.com/chat?token=your_jwt.
- Pros: Simple to implement.
- Cons: Can expose sensitive tokens in server logs or browser history. Generally less secure and not recommended for production.
Passing Credentials: HTTP Headers
A more secure and recommended approach is to pass authentication tokens within HTTP headers during the handshake.
While the standard WebSocket API doesn't directly support custom headers, some libraries or proxy configurations allow this. Often, custom headers like Authorization: Bearer your_jwt are used, or tokens are embedded in the Sec-WebSocket-Protocol header.
What is a JSON Web Token (JWT)?
A JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. It's often used for authentication.
- It's digitally signed, ensuring its authenticity.
- It contains user information (like user ID, roles) in a payload.
- The server verifies the JWT signature to confirm the user's identity.
Server-Side JWT Handshake (Node.js)
Here's a simplified Node.js example using the ws library showing how a server might verify a JWT from a query parameter during the handshake. In a real app, you'd use a robust JWT library.
const WebSocket = require('ws');
const url = require('url');
const wss = new WebSocket.Server({ noServer: true });
wss.on('connection', function connection(ws, request) {
const userId = request.userId; // Set during handshake verification
console.log(`Client ${userId} connected`);
ws.on('message', function incoming(message) {
console.log(`Received from ${userId}: ${message}`);
});
ws.on('close', () => console.log(`Client ${userId} disconnected`));
});
// This is where you would integrate with an HTTP server
// For simplicity, we'll simulate the handshake here.
// Simulate an HTTP server upgrade listener
// In a real app, this would be an http.Server.on('upgrade')
function handleUpgrade(request, socket, head) {
const pathname = url.parse(request.url).pathname;
if (pathname === '/ws') {
const token = new URLSearchParams(url.parse(request.url).query).get('token');
// --- Simulate JWT verification ---
if (token === 'valid_jwt_123') {
request.userId = 'user_1'; // Attach user info to request
wss.handleUpgrade(request, socket, head, function done(ws) {
wss.emit('connection', ws, request);
});
} else {
console.log('Invalid JWT. Connection rejected.');
socket.destroy();
}
} else {
socket.destroy();
}
}
// Example usage (not a full http server, just for demonstration)
const mockRequest = {
url: '/ws?token=valid_jwt_123',
headers: { 'upgrade': 'websocket', 'connection': 'upgrade' }
};
const mockSocket = {
destroy: () => console.log('Socket destroyed (connection rejected)')
};
const mockHead = Buffer.alloc(0);
console.log('Attempting connection with valid token...');
handleUpgrade(mockRequest, mockSocket, mockHead);
// Attempt connection with invalid token
const mockInvalidRequest = {
url: '/ws?token=invalid_jwt',
headers: { 'upgrade': 'websocket', 'connection': 'upgrade' }
};
const mockInvalidSocket = {
destroy: () => console.log('Socket destroyed (connection rejected)')
};
console.log('\nAttempting connection with invalid token...');
handleUpgrade(mockInvalidRequest, mockInvalidSocket, mockHead);Authorization: Who Can Do What?
Once a user is authenticated (we know who they are), authorization determines what actions they are permitted to perform.
This often involves checking user roles or permissions associated with their authenticated identity. For example, a 'guest' user might only be able to read messages, while an 'admin' can also delete them.
Message-Level Authorization (Node.js)
After a WebSocket connection is established and the user is authenticated, the server can enforce authorization rules on incoming messages. This example shows a simple check based on a user's role.
const WebSocket = require('ws');
// Simulate a WebSocket server for demonstration
const wss = new WebSocket.Server({ port: 8080 });
// In a real application, user info (like roles) would be
// stored in the ws object after successful authentication.
const connectedClients = new Map(); // Map ws -> { userId, role }
wss.on('connection', function connection(ws) {
// Simulate authenticated user and their role
const userId = `user_${Math.floor(Math.random() * 100)}`;
const role = (userId === 'user_10') ? 'admin' : 'member';
connectedClients.set(ws, { userId, role });
console.log(`Client ${userId} (${role}) connected.`);
ws.send(`Welcome, ${userId}! Your role is ${role}.`);
ws.on('message', function incoming(message) {
const clientInfo = connectedClients.get(ws);
const msg = message.toString();
console.log(`Received from ${clientInfo.userId}: ${msg}`);
// --- Authorization Check ---
if (msg.startsWith('/delete') && clientInfo.role !== 'admin') {
ws.send('Error: You are not authorized to delete messages.');
console.log(`${clientInfo.userId} (member) tried to delete.`);
} else if (msg.startsWith('/delete') && clientInfo.role === 'admin') {
ws.send('Message deleted successfully!');
console.log(`${clientInfo.userId} (admin) deleted a message.`);
// In a real app, delete logic would go here
} else {
// Broadcast message to others or process normally
wss.clients.forEach(function each(client) {
if (client !== ws && client.readyState === WebSocket.OPEN) {
client.send(`${clientInfo.userId}: ${msg}`);
}
});
ws.send(`You said: ${msg}`);
}
});
ws.on('close', () => {
const clientInfo = connectedClients.get(ws);
console.log(`Client ${clientInfo.userId} disconnected.`);
connectedClients.delete(ws);
});
});
console.log('WebSocket server started on port 8080. Try connecting with a WebSocket client!');
console.log('Simulated user_10 is an admin, others are members.');Auth & Auth Quick Check
When is the most appropriate and secure time to authenticate a client in a WebSocket connection?
Recap: Secure Connections
We've explored how to secure WebSocket connections by implementing authentication and authorization.
- Authentication happens primarily during the handshake, often using JWTs passed in headers.
- Authorization determines user permissions, controlling what actions they can take over the established connection.
- These mechanisms are vital for protecting your real-time applications from unauthorized access and actions.
常见问题解答
「身份验证与授权」课时是免费的吗?
是的 — 「身份验证与授权」的完整文本可在网页上免费阅读。要进行交互式练习(内置代码编辑器和全天候 AI 导师)并解锁 WebSockets & Realtime Systems Programming 课程的其余内容,请升级到 CoddyKit PRO。 WebSockets & Realtime Systems Programming 课程共包含 4 节课。
「身份验证与授权」这节课中我会学到什么?
在握手期间集成身份验证机制(例如 JWT),并管理 WebSocket 消息的用户权限。 你通过在浏览器中直接运行的动手代码来练习 WebSockets & Realtime Systems Programming,全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 WebSockets & Realtime Systems Programming 需要有经验吗?
无需任何先前经验。CoddyKit 上的 WebSockets & Realtime Systems Programming 课程适合初学者到高级学习者,你可以从这里开始或从头开始,按照自己的节奏学习。 这是第 2 节课,共 4 节。
「身份验证与授权」课时需要多长时间?
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动,所以你能稳步进步,并在网页和应用中从离开的地方继续。
我能在这节 WebSockets & Realtime Systems Programming 课中编写并运行代码吗?
能。每节 WebSockets & Realtime Systems Programming 课都包含内置代码编辑器,你可以在浏览器中直接编写并运行真实代码,并获得即时 AI 反馈 — 无需本地设置。