In this article, we explain HTTP protocols and related Request-Response cycle jargon in a simple and clear manner. To make it more relatable, we use a real-world example in Hinglish and include a diagram, helping you easily understand how web communication works.
HTTP
HTTP (HyperText Transfer Protocol) is the foundation of data communication on the web. It's a set of rules that define how messages are sent and received between a client (like a web browser) and a server (where the website or application is hosted).
Breaking down HTTP
HyperText:
Hypertext means text that is linked to other pieces of information. In simple words, it refers to the clickable text on websites (like links). So when you click on a link, you're moving from one "piece of text" to another, hence "hypertext."
Example: "Yeh jo text hai, jo tum click kar sakte ho, usse hum keh sakte hain hypertext. Jaise tumhare browser mein 'click here' likha hota hai, voh hypertext hota hai."
Transfer:
Transfer means to send something from one place to another. In HTTP's case, it’s sending data (like text, images, videos) from a server to your browser or browser to server.
Example: "Agar tumhe koi image ya website ka page dekhna hai, toh wo data server se tumhare browser mein transfer hota hai."
Protocol:
Protocol is just a fancy word for a set of rules or guidelines. HTTP is a protocol because it sets the rules for how data (like website content) should be transferred over the internet.
Example: "Protocol ka matlab hota hai rules ka set. Jaise tumhare ghar mein rules hote hain, waise HTTP ka apna set of rules hota hai jo decide karta hai ki data kaise bheja jaayega."
Putting it all together
HTTP is a system that helps web browsers (clients) and web servers talk to each other using specific rules to transfer hypertext (links, text, images, etc.). Whenever you enter a website URL in your browser, HTTP is responsible for asking the server to send that website data to you.
Example: "Jab tum apne browser mein website ka URL type karte ho, toh tumhara browser HTTP ko use karke server se website ka data mangta hai, aur phir woh data tumhare screen par dikhai deta hai."
Stateless HTTP
Stateless HTTP means that each HTTP request is independent of previous or future requests. In simple terms, the server doesn't remember anything about the previous requests from the client once a request is completed.
Breaking it down
Stateless:
Stateless means the server doesn't store any memory or information about past interactions. After sending the response to the client (like showing a webpage), it forgets everything about that request. The server doesn’t "remember" anything about you or your previous requests.
Example: "Maan lo tumne server se kuch request kiya jaise ek webpage dekhna, toh server woh response dega aur fir us request ko bilkul bhool jaayega. Agli baar jab tum request karoge, server ko kuch yaad nahi hoga."
HTTP (HyperText Transfer Protocol):
HTTP itself is stateless. Each time you make a new request to a website, it is treated as a completely new interaction, even if it’s part of the same session. The server doesn't retain any info about your last visit.
Example: "Jab tum website pe click karte ho, har baar ek nayi request hoti hai aur server ko pichli baar ke baare mein kuch bhi yaad nahi hota."
Sessions & Cookies
Cookies
What is a Cookie?
A cookie is a small piece of data that is stored on the client’s browser (your computer or device). It is sent to the server with every request made to the same domain.
Cookies are typically used to store information about the user’s preferences, login status, or shopping cart items.
How Do Cookies Work?
When you visit a website, the server can send a cookie to your browser. Your browser will store this cookie, and each time you make a request to that same website, your browser sends the stored cookie back to the server.
Cookies can store small amounts of data, like a user’s name, session ID, or any other data that the website needs to remember between visits.
Example: "Maan lo tum ek shopping website pe ho, aur tumhara login ho gaya hai. Ab tum jab website ko request karte ho, server tumhare browser ko ek cookie bhejta hai. Jab tum next page pe jaate ho, tumhara browser wo cookie server ke saath bhejta hai, jisse server tumhe firse login karne ki zarurat nahi samajhta."
Sessions
What is a Session?
- A session is a way to store data on the server-side that is specific to a user. A session is created when a user logs in or starts interacting with a website, and a session ID is generated and stored in the user's browser as a cookie. The server uses this session ID to retrieve the corresponding session data stored on the server.
How Do Sessions Work?
When a user logs in or starts interacting with a website, the server creates a session and generates a unique session ID.
This session ID is sent to the user’s browser as a cookie. The browser then sends this session ID back to the server with every request.
On the server, the session data (like login information or user preferences) is stored in memory or a database. The session ID is used to access this data.
Example: “Jab tum website pe login karte ho, toh server ek session create karta hai, aur us session ko ek ID assign karta hai. Server tumhare browser ko yeh ID cookie ke form mein bhejta hai. Jab tum agli baar page request karte ho, toh tumhara browser yeh session ID server ke saath bhejta hai, aur server uss ID ke through tumhara data access karta hai, jaise tumhare cart ke items ya personal info, aur tumhe wahi information dikhata hai.”
HTTP Request
HTTP requests are used to interact with a server. There are several types of HTTP requests, known as HTTP methods or request types, each serving a specific purpose.
1. GET
Purpose: Used to retrieve data from a server. It doesn't change anything on the server and is used when you want to get information, such as loading a webpage.
Example: When you visit a website, the browser sends a GET request to the server to fetch the page.
Explanation: "Jab tum kisi webpage ko visit karte ho, toh browser ek GET request bhejta hai server ko taaki wo page tumhe dikhaye."
2. POST
Purpose: Used to send data to the server, typically to create a new resource. This method often sends data via the request body (e.g., form data or JSON) and can change data on the server.
Example: When you submit a form, such as signing up for an account, a POST request is sent to the server.
Hinglish Explanation: "Agar tum koi form fill karte ho aur submit karte ho, toh ek POST request server ko bheja jata hai, jisme tumhara data hota hai."
3. PUT
Purpose: Used to update an existing resource on the server. It replaces the current representation of the resource with the data sent in the request.
Example: Updating your profile information on a website would typically use a PUT request.
Hinglish Explanation: "Agar tum apni profile ko update karte ho, jaise apna address change karna, toh server ko PUT request bheja jata hai."
4. DELETE
Purpose: Used to delete a resource on the server.
Example: If you delete an account or a product from your shopping cart, the server will receive a DELETE request.
Hinglish Explanation: "Agar tum apni account ko delete karte ho ya shopping cart se koi item nikaalte ho, toh server ko DELETE request bheji jaati hai."
HTTP/2
HTTP/2 is an upgraded version of the HTTP/1.1 protocol designed to make web browsing faster, more efficient, and secure. It introduces significant improvements over HTTP/1.1 while maintaining compatibility with existing websites.
Key Features of HTTP/2
Multiplexing: Multiple requests and responses can be sent simultaneously over a single connection, eliminating the need for multiple TCP connections.
- Example: Ek webpage ke multiple images ek sath load hote hain, isse page jaldi open hota hai.
Header Compression: HTTP/2 reduces the size of HTTP headers using a technique called HPACK compression, saving bandwidth.
- Example: Repeat hone wale headers, jaise cookies ya user-agent, kam space lete hain.
Server Push: The server can proactively send resources (like CSS or JS files) to the client before it even asks for them, reducing latency.
- Example: Website ka stylesheet pehle hi browser ko bhej diya jata hai.
Binary Protocol: HTTP/2 uses a binary format instead of the text-based format in HTTP/1.1, making communication between the client and server faster and less error-prone.
Secure by Default: Although not mandatory, most HTTP/2 implementations work over HTTPS, enhancing security.
TLS
TLS (Transport Layer Security) is a cryptographic protocol designed to provide secure communication over a network, like the internet. It ensures that data exchanged between a client (e.g., a browser) and a server is encrypted, authenticated, and protected from tampering.
Key Features of TLS
Encryption: Protects data from being read by unauthorized parties during transmission.
- Hinglish Example: "TLS data ko encrypt karta hai, taaki koi beech mein data ko padh na sake."
Authentication: Verifies that the server (and sometimes the client) is who it claims to be.
- Hinglish Example: "Server ka identity verify karna, taaki tumhe ek trusted connection mile."
Integrity: Ensures that data is not altered or tampered with during transit.
- Hinglish Example: "Data jab server se client tak jaye, toh woh safe aur unchanged rahe."
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HTTPS me "S" ka matlab Secure hota hai, aur yeh TLS (Transport Layer Security) ki wajah se hota hai.
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User Agent
User Agent refers to the software or tool (usually a web browser, mobile app, or bot) that acts on behalf of a user to interact with websites or servers. When a client (like a browser) makes a request to a server, it sends a User-Agent string as part of the HTTP header to identify itself.
Real World Example
Think of a restaurant where the waiter (representing the user-agent) takes your order (request) and passes it to the chef (the server). The waiter needs to know a few details about you, like whether you are ordering for dine-in or takeaway, and your preferences (allergies, preferred spice level, etc.) so the chef can prepare the food accordingly.
Waiter (User-Agent): Identifies you as a customer (like your phone or browser).
Your Order (Request): The details of your preferences, just like how a browser sends details like the operating system or device.
Chef (Server): Prepares the food based on the information the waiter gives them, like a server responding to the request based on the User-Agent details.
TCP
TCP (Transmission Control Protocol) ek communication protocol hai jo data ko reliable tareeke se ek device se doosre device tak bhejne ke liye use hota hai. Yeh ensure karta hai ki data sahi tarike se aur bina kisi loss ke transfer ho.
Real-World Example: “TCP ko hum ek registered post ke example se samajh sakte hain. Jab tum ek important letter bhejte ho, toh post office yeh ensure karta hai ki letter safe delivery ke liye receiver ke paas pohoch jaaye. Agar letter lost ho jaata hai, toh post office dubara bhejta hai. Is process mein, post office sender aur receiver ko baar-baar confirm karta hai ki letter sahi haath mein gaya hai.”
Bas waise hi, TCP bhi data ke safe aur accurate transfer ke liye apne steps follow karta hai!
FTP
FTP (File Transfer Protocol) is a standard network protocol used to transfer files from one computer to another over a network, like the internet or a local network. It allows users to upload or download files to and from a server.
Real-World Example: “FTP ko samajhne ke liye socho, tumhare paas ek parcel hai jise tumhe apne dost ko bhejna hai. Tum courier service ka use karte ho, jahan tum parcel ko courier ko dete ho, aur wo parcel tumhare dost tak safely pahucha deta hai. Waise hi, FTP tumhare computer se file ko server ya doosre computer tak bhejta hai aur wahan se file ko receive karne mein madad karta hai.”
IP
IP (Internet Protocol) is a system that assigns a unique address to every device connected to the internet or a network. This address, known as an IP address, helps identify devices and manage data transfer between them.
Example: “IP ko samajhne ke liye, socho tumhare paas ek house address hai. Jab koi dost tumhare ghar aata hai, to wo address use karke tumhare ghar tak pahuchta hai. Waise hi, IP address har device ka ek unique address hota hai, jise use karke data us device tak pahuchta hai. Jaise tumhara ghar address specific hota hai, waise har device ka IP address bhi unique hota hai.”
URL
URL (Uniform Resource Locator) is the address used to access a specific resource on the internet, like a website, page, or file. It’s essentially the web address that directs you to a particular location on the internet.
Example: “Socho URL ek road address jaise hota hai. Agar tumhe kisi particular jagah pe jaana hai, toh tum us jagah ka address use karte ho, jaise "123 Main Street". Waise hi, URL ek address hota hai jo tumhe kisi specific website ya webpage tak pahuchata hai.”
DNS
DNS (Domain Name System) is like the phonebook of the internet. It translates human-readable domain names (like www.example.com) into IP addresses (which computers use to identify each other).
Real-World Example: “Socho DNS ek telephone directory jaise hota hai. Jab tumhe apne kisi dost ka phone number chahiye, tum directory me uska naam dhoondte ho, aur fir uska number pata chal jata hai. Waise hi, jab tum example.com type karte ho, DNS us naam ko computer-friendly IP address me convert karta hai, taki tumhara device us website tak pahuch sake.”
Header
Header in the context of HTTP is a part of the request or response that contains meta-information about the communication. It includes details like the type of content being sent, the length of the data, or the status of the response.
Real-World Example: “Socho header ek letter ka envelope hai. Jab tum letter bhejte ho, tum envelope par recipient ka address, date, aur doosre details likhte ho. Yeh details letter ke baare mein extra information hoti hain, jo us letter ko deliver karne mein madad karti hain. Waise hi, HTTP header web requests aur responses mein important information (like content type, length, etc.) ko carry karta hai.”
Payload
Payload refers to the actual data or content that is transferred in a request or response. In an HTTP request, it’s the data you send to the server, and in a response, it's the data sent back from the server (like the content of a webpage).
Real-World Example: “Socho payload ek parcel ka andar ka saman hai. Jab tum ek parcel bhejte ho, usme jo asli cheez hoti hai (jaise koi gift ya document), wo payload hai. Envelope ya box to bas uss saman ko transfer karne ka medium hota hai. Waise hi, HTTP request ya response mein, jo actual content transfer hota hai, wo payload hota hai. Jaise tum form submit karte ho, usme jo data tum bhejte ho, wo payload hai.”
Cache
Cache is a storage location where data is temporarily saved for quick access. It helps to speed up future requests by storing copies of frequently accessed data, so the system doesn’t have to retrieve it from scratch each time.
Real-World Example: “Socho cache ek restaurant ka menu hai. Jab tum baar-baar ek hi dish order karte ho, restaurant staff tumhare favorite dish ko pehle se ready rakh leta hai, taki tumhe jaldi se mile. Waise hi, jab tum baar-baar kisi website ko visit karte ho, browser us website ka data cache mein store kar leta hai, taki next time jab tum visit karo, wo jaldi load ho jaye.”