Bits of .NET

📊 HTTP Status Codes = Server’s Response

200 OK, 404 Not Found, 500 Server Error. Status codes tell what happened. Know them for debugging.

📝 Status Code Groups

2xx: Success
- 200 OK: Request successful
- 201 Created: Resource created
- 204 No Content: Success, no response body

3xx: Redirection
- 301 Moved Permanently: URL changed
- 302 Found: Temporary redirect
- 304 Not Modified: Cache

4xx: Client Error
- 400 Bad Request: Invalid request
- 401 Unauthorized: Authentication required
- 403 Forbidden: Not allowed
- 404 Not Found: Resource doesn't exist
- 405 Method Not Allowed: Wrong HTTP method
- 429 Too Many Requests: Rate limit

5xx: Server Error
- 500 Internal Server Error: Server error
- 502 Bad Gateway: Proxy error
- 503 Service Unavailable: Server down
- 504 Gateway Timeout: Proxy timeout

🎯 Handling Status Codes

fetch('/api/users')
  .then(response => {
    if (response.status === 404) {
      console.log('User not found');
    } else if (response.status === 401) {
      console.log('Unauthorized');
    } else if (response.status === 500) {
      console.log('Server error');
    } else if (response.ok) {
      return response.json();
    }
    throw new Error('Request failed');
  })
  .then(data => console.log(data))
  .catch(error => console.error('Error:', error));

// Axios (handles status codes differently)
try {
  const response = await axios.get('/api/users');
  console.log(response.data);
} catch (error) {
  if (error.response.status === 404) {
    console.log('Not found');
  } else if (error.response.status === 500) {
    console.log('Server error');
  }
}

💡 Common Errors

• 404: Resource not found (check URL)
• 401: Need authentication (add token)
• 403: Not allowed (check permissions)
• 400: Invalid request (check payload)
• 500: Server error (check server logs)