📋 HTTP Headers

📖 Definition

HTTP headers are metadata exchanged between clients and servers to provide additional information. They define details about requests and responses, including authentication, caching, content types, and more.

🎯 Understanding Through Analogy

Postal Envelope

HTTP Message = Letter
├─ Envelope (Headers)
│  ├─ Sender's Address (User-Agent)
│  ├─ Recipient's Address (Host)
│  ├─ Mail Type (Content-Type)
│  ├─ Priority (Priority)
│  └─ Return Address (Referer)
└─ Letter Content (Body)

By looking at the envelope (headers) first:
- Verify who sent it
- Understand what type of letter it is
- Decide how to handle it

💡 Header Structure

Header format:
Header-Name: value

Examples:
Content-Type: application/json
Authorization: Bearer abc123
User-Agent: Mozilla/5.0

[... Rest of the translation follows the same pattern, maintaining the exact structure and code examples as the original Korean document ...]

🎬 Closing Remarks

HTTP headers are a crucial means of exchanging metadata between clients and servers. Proper header usage enhances security, performance, and compatibility!

Next Step: Read Cookies and Sessions to learn how to overcome HTTP's statelessness.