Bits of .NET

📋 Headers = Request Metadata

API needs authentication, content type, custom data. Request headers send additional info. Essential for API integration.

📝 Sending Headers

// Fetch with headers
const response = await fetch('/api/data', {
  headers: {
    'Content-Type': 'application/json',
    'Authorization': 'Bearer your-token',
    'X-API-Key': 'your-api-key',
    'Accept': 'application/json'
  }
});

// With authentication
const token = 'jwt-token-here';
await fetch('/api/protected', {
  headers: {
    'Authorization': `Bearer ${token}`
  }
});

// Multiple custom headers
await fetch('/api/custom', {
  headers: {
    'X-Request-ID': crypto.randomUUID(),
    'X-Client-Version': '1.0.0',
    'X-Environment': 'production'
  }
});

// Using Headers constructor
const headers = new Headers();
headers.append('Authorization', `Bearer ${token}`);
headers.append('Content-Type', 'application/json');
const response = await fetch('/api/data', { headers });

🎯 Common Headers

// Authentication
Authorization: Bearer 
X-API-Key: 

// Content
Content-Type: application/json
Content-Type: application/x-www-form-urlencoded
Accept: application/json

// Caching
Cache-Control: no-cache
If-Modified-Since: Mon, 15 Jan 2024 12:00:00 GMT

// Client info
User-Agent: MyApp/1.0.0
Accept-Language: en-US

// Custom
X-Request-ID: unique-id
X-Client-Version: 1.0.0
X-Environment: production

💡 Best Practices

• Set Content-Type for POST/PUT requests
• Send Authorization token for protected APIs
• Use X-Request-ID for tracing
• Don’t send sensitive data in headers
• Check API documentation for required headers