HTTP Headers kya hai?

 

HTTP Headers kya hai?

HTTP Headers web browser aur server ke beech hone wali communication (message) ka ek part hote hain.
Ye headers browser ya server ko important information dete hain — jaise content type, language, security, cookies, cache rules, etc.

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✅ Simple Definition:

HTTP Headers wo short messages hote hain jo HTTP request aur HTTP response ke sath send hote hain — ye batate hain ki data kaise handle karna hai.

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🧩 2 Types of HTTP Headers:

Type	Kaun send karta hai?
✅ Request Headers	Browser → Server ko bhejta hai
✅ Response Headers	Server → Browser ko bhejta hai

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🔄 HTTP Communication Example:

1. 🧑‍💻 User browser me type karta hai:
   https://example.com

2. 📤 Browser send karta hai Request + Headers
   (e.g., User-Agent, Accept-Language, etc.)

3. 📥 Server send karta hai Response + Headers
   (e.g., Content-Type, Cache-Control, Set-Cookie, etc.)

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🔍 Common HTTP Headers (With Explanation):

📤 Request Headers:

Header	Meaning
User-Agent	Kaunsa browser/device use ho raha hai
Accept	Browser kaunsa content format chahta hai (e.g., text/html, application/json)
Accept-Language	Language preference (e.g., en-US, hi-IN)
Authorization	Secure access ke liye token/password
Cookie	Client-side stored cookies server ko bhejta hai

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📥 Response Headers:

Header	Meaning
Content-Type	Server ne kaunsa content bheja (e.g., text/html, image/png)
Cache-Control	Browser kitne time tak content cache kare
Set-Cookie	Server client me new cookie set karta hai
Location	Redirection ke liye naya URL
Access-Control-Allow-Origin	CORS ke liye (kya allow hai, kya nahi)

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🔐 Example Response Header:

http
HTTP/1.1 200 OK  
Content-Type: text/html  
Cache-Control: no-cache  
Set-Cookie: session_id=12345; Path=/;  

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🎯 HTTP Headers Kyu Important Hai?

Use Case	Explanation
✅ Security	Authentication, cookies, access control
✅ Performance	Caching, compression, file type handling
✅ SEO & Analytics	Language, geo-location, redirect info
✅ Cross-Origin (CORS)	3rd-party access control