Mini HTTP Server (Java)

A minimal web server built from scratch using pure Java sockets.
No frameworks. No Spring. Just HTTP.

The purpose of this project is to understand what actually happens behind modern backend frameworks by implementing the core mechanics manually.

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✨ Features

• Accepts real browser connections
• Parses HTTP requests (method, path, headers)
• Routes requests based on URL
• Generates valid HTTP responses
• Automatic 404 Not Found
• Clear separation between networking and application logic

You can open it in Chrome and it behaves like a real backend server.

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🏗 Architecture

Browser ↓ TCP Connection ↓ SocketServer ↓ HttpParser ↓ Router ↓ HttpResponse ↓ Browser

Responsibility per component

Component	Responsibility
SocketServer	Handles TCP connections
HttpParser	Converts raw request text → HttpRequest object
Router	Chooses which handler should run
HttpResponse	Builds valid HTTP response text

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🌐 Example Routes

Route	Result
/	Welcome message
/health	OK
unknown path	404 Not Found

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🚀 Run the server

1. Clone

git clone https://github.com/lindaeskilsson/mini-server.git
cd mini-server
2. Start
Run via IDE or terminal:

mvn compile
mvn exec:java -Dexec.mainClass="org.example.index.http.MyServer"
Server starts on:

http://localhost:4000
🧪 Test
Browser:

http://localhost:4000/
http://localhost:4000/health
http://localhost:4000/anything
Terminal:

curl -v http://localhost:4000/health
📚 Implemented HTTP Concepts
Request line parsing

Header parsing

Status codes

Content-Length handling

Routing

Layered architecture

This mirrors the core of real backend frameworks — without abstraction.


🎯 Learning Goal
The project demonstrates that a web server is fundamentally:
- A TCP loop + a text protocol + a function map
- Frameworks simply automate this.

👤 Author
Linda Eskilsson
Java Developer Student