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Understanding HTTP Methods and Status Codes

A comprehensive guide to HTTP methods and their status codes

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Overview

HTTP methods define how clients communicate with web servers. Let’s explore each method and their corresponding status codes.

graph TD; A[HTTP Request Methods] --> B[🔍 GET Request]; A --> C[POST Request]; A --> D[HEAD Request]; B --> B1[Used when typing URL in browser]; B1 --> B2[GET /cat.png]; B2 --> B3[200 OK \n Content-Type: image/png]; B3 --> B4[Display Cat Image]; C --> C1[Submitting a form]; C1 --> C2[POST /sign_up \n Content-Type: application/json]; C2 --> C3[200 OK \n Content-Type: text/html]; C3 --> C4[Display Sign-up Page]; D --> D1[Similar to GET but no response body]; D1 --> D2[HEAD /cat.png]; D2 --> D3[200 OK \n Content-Type: image/png]; D3 --> D4[No image, only headers]; %% Explanation B -.-> E[GET: Usually no request body]; C -.-> F[POST: Usually sends data in request body]; E -.-> G[GET doesn't change server state]; F -.-> H[POST can change server state];


🔍 HTTP Methods


GET

  • Used for retrieving information
  • Read-only operations
  • Doesn't modify server data

POST

  • Creates new resources
  • Sends data to server
  • More secure than GET for data transmission

HEAD

  • Similar to GET but returns headers only
  • No response body
  • Efficient for metadata checks

PUT

  • Updates entire resource
  • Creates if doesn't exist
  • Requires complete resource data

DELETE

  • Removes specified resource
  • Usually returns empty response
  • Should be used carefully

PATCH

  • Partial resource modification
  • More efficient than PUT
  • Updates specific fields

OPTIONS

  • Lists available methods
  • Returns "Allow" header
  • Used for API discovery

TRACE

  • Diagnostic purposes
  • Returns exact request
  • Debugging tool

CONNECT

  • Creates network tunnel
  • Used for SSL/TLS
  • Proxy connections


📊 HTTP Status Codes


ℹ️

1xx (Informational)

Request received

Processing continues

✅

2xx (Success)

Request succeeded

Data received and accepted

🔀

3xx (Redirection)

Additional action needed

Resource moved

🚫

4xx (Client Error)

Invalid request

Resource not found

⚠️

5xx (Server Error)

Server failed

Internal issues


Reference