How to develop whistle plugins and what is the basic structure of plugins?

Answer

Whistle supports a plugin system that allows extending its functionality by developing plugins to implement custom network request processing logic.

Plugin Development Basics

1. Create Plugin Project

bash
mkdir whistle-plugin-demo
cd whistle-plugin-demo
npm init -y

2. Create Plugin Entry File

Create index.js file:

javascript
module.exports = function(server, options) {
  // Plugin initialization logic
  console.log('Whistle plugin demo loaded');
  
  // Listen to request events
  server.on('request', function(req, res) {
    // Handle request
    if (req.url === '/api/plugin-demo') {
      res.writeHead(200, { 'Content-Type': 'application/json' });
      res.end(JSON.stringify({ 
        message: 'Hello from whistle plugin',
        timestamp: Date.now()
      }));
    }
  });
  
  // Listen to response events
  server.on('response', function(req, res) {
    // Handle response
    console.log('Response:', req.url, res.statusCode);
  });
};

3. Configure package.json

json
{
  "name": "whistle-plugin-demo",
  "version": "1.0.0",
  "description": "A demo whistle plugin",
  "main": "index.js",
  "whistleConfig": {
    "name": "demo",
    "description": "Demo plugin for whistle"
  }
}

Plugin Functionality Implementation

1. Request Interception and Modification

javascript
module.exports = function(server, options) {
  server.on('request', function(req, res) {
    // Modify request headers
    req.headers['X-Custom-Header'] = 'Custom Value';
    
    // Log request information
    console.log('Request URL:', req.url);
    console.log('Request Method:', req.method);
    console.log('Request Headers:', req.headers);
  });
};

2. Response Interception and Modification

javascript
module.exports = function(server, options) {
  server.on('response', function(req, res) {
    // Modify response headers
    res.setHeader('X-Response-Header', 'Custom Response');
    
    // Modify response body
    const originalEnd = res.end;
    res.end = function(chunk, encoding) {
      if (chunk) {
        const body = chunk.toString();
        const modifiedBody = body.replace(/old/g, 'new');
        originalEnd.call(res, modifiedBody, encoding);
      } else {
        originalEnd.call(res, chunk, encoding);
      }
    };
  });
};

3. Middleware Pattern

javascript
module.exports = function(server, options) {
  // Use Express-style middleware
  server.use(function(req, res, next) {
    console.log('Middleware:', req.url);
    next();
  });
  
  // Route handling
  server.get('/api/test', function(req, res) {
    res.json({ success: true });
  });
};

Plugin Configuration Options

javascript
module.exports = function(server, options) {
  // Get plugin configuration
  const customConfig = options.customConfig || {};
  const port = options.port || 3000;
  
  console.log('Plugin options:', options);
};

Installing and Using Plugins

1. Local Plugin Installation

bash
cd whistle-plugin-demo
npm link
w2 install demo

2. Global Plugin Installation

bash
npm install -g whistle-plugin-demo
w2 install demo

3. Use Plugin in Rules

shell
www.example.com plugin://demo

Advanced Features

1. WebSocket Support

javascript
module.exports = function(server, options) {
  server.on('upgrade', function(req, socket, head) {
    // Handle WebSocket upgrade requests
    console.log('WebSocket upgrade:', req.url);
  });
};

2. File System Operations

javascript
const fs = require('fs');
const path = require('path');

module.exports = function(server, options) {
  server.on('request', function(req, res) {
    if (req.url === '/api/file') {
      const filePath = path.join(__dirname, 'data.json');
      const data = fs.readFileSync(filePath, 'utf8');
      res.end(data);
    }
  });
};

3. Database Integration

javascript
const mysql = require('mysql');

module.exports = function(server, options) {
  const connection = mysql.createConnection({
    host: 'localhost',
    user: 'root',
    password: 'password',
    database: 'test'
  });
  
  server.on('request', function(req, res) {
    if (req.url === '/api/users') {
      connection.query('SELECT * FROM users', function(error, results) {
        if (error) {
          res.statusCode = 500;
          res.end(JSON.stringify({ error: error.message }));
        } else {
          res.end(JSON.stringify(results));
        }
      });
    }
  });
};

Best Practices

1. Error Handling

   • Add appropriate error handling logic
   • Log errors
   • Provide friendly error messages

2. Performance Optimization

   • Avoid blocking operations
   • Use caching to reduce repeated calculations
   • Use async operations appropriately

3. Security

   • Validate input parameters
   • Prevent injection attacks
   • Encrypt sensitive information

4. Documentation and Testing

   • Write clear usage documentation
   • Add unit tests
   • Provide example code