Understanding HTTP Requests

 

🌐 Understanding HTTP Requests: Request Line, Methods, Headers & Body

When you visit a website, log in, or submit a form, your browser sends something called an HTTP request to the server. If you're learning about web development or cybersecurity, understanding this is super important!

Let’s break it down into four main parts:

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📌 1. Request Line (Start Line)

The request line is the first part of the HTTP request. It tells the server:

• What to do (method)

• Where to do it (path)

• How to communicate (HTTP version)

✨ Example:

pgsqlCopyEditGET /login HTTP/1.1

🔹 It includes:

• Method – Example: GET, POST, etc.

• Path – The URL path. Example: /login

• Version – Like HTTP/1.1, HTTP/2, etc.

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🔧 2. HTTP Methods

Each method tells the server what kind of action the user wants to perform.

Method	Purpose	Security Tip 🔒
GET	Retrieve data	Don’t send sensitive info like passwords
POST	Send data (like login info)	Always validate input
PUT	Update or replace data	Check user permission
DELETE	Delete data	Only allow authorised users
PATCH	Update part of a resource	Validate data carefully
HEAD	Like GET, but no body	Used to check metadata
OPTIONS	Lists allowed methods	Can be disabled if not needed
TRACE	Debugging tool	Disable it for security
CONNECT	Creates secure tunnel (HTTPS)	Used in secure browsing

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📥 3. Request Headers

Request headers give extra details about the request. These help the server understand how to handle it.

🔹 Common Headers:

Header	Example	What It Does
Host	Host: tryhackme.com	Tells which website the request is for
User-Agent	User-Agent: Mozilla/5.0	Info about the browser or client
Referer	Referer: https://www.google.com/	Shows where the user came from
Cookie	Cookie: user_type=student; room_status=in_progress	Sends stored data like login/session info
Content-Type	Content-Type: application/json	Describes the format of data in the body

📌 Fill in the blanks?
_______ _______ = Request Headers ✅

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🧾 4. Request Body

The request body carries data when the client is sending something to the server — usually with POST or PUT methods.

🧠 Formats used in the body:

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🔸 a) URL Encoded (application/x-www-form-urlencoded)

• Key-value pairs like: key1=value1&key2=value2

• Common in login forms

httpCopyEditPOST /profile HTTP/1.1
Content-Type: application/x-www-form-urlencoded

name=Aleksandra&age=27&country=US

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🔸 b) Form Data (multipart/form-data)

• Used for uploading files or images

• Data is split using a boundary

httpCopyEditPOST /upload HTTP/1.1
Content-Type: multipart/form-data; boundary=----boundary123

----boundary123
Content-Disposition: form-data; name="username"

aleksandra
----boundary123
Content-Disposition: form-data; name="profile_pic"; filename="aleksandra.jpg"
Content-Type: image/jpeg

[Binary image data here]
----boundary123--

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🔸 c) JSON (application/json)

• Common in APIs

• Uses key-value pairs with curly braces

hCopyEditPOST /api/user HTTP/1.1
Content-Type: application/json

{
  "name": "Aleksandra",
  "age": 27,
  "country": "US"
}

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🔸 d) XML (application/xml)

• Uses opening and closing tags

• Example of nested data

httpCopyEditPOST /api/user HTTP/1.1
Content-Type: application/xml

<user>
  <name>Aleksandra</name>
  <age>27</age>
  <country>US</country>
</user>

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✅ Quick Recap

• Default content type for forms? → application/x-www-form-urlencoded

• Where is Host, User-Agent, Content-Type found? → Request Headers