Implement static file handler (foundation for #18)

[annikaholmqvist94]

Changes

Foundation work for #18 - GET handling for static files

What's Added

Core Logic

• StaticFileHandler - Serves files from /resources/static/
• MimeTypeResolver - Maps file extensions to Content-Type headers

Security Features

• Path validation prevents directory traversal attacks
• Blocks suspicious patterns: ../, //, \
• Returns 403 Forbidden for security violations
• Comprehensive security tests included

Testing (35+ test cases)

MimeTypeResolverTest (15 tests):

• HTML, CSS, JS, image formats
• Edge cases: null, empty, unknown extensions
• Case-insensitive extension handling
• Path handling with directories

StaticFileHandlerTest (20+ tests):

• Successful file serving (200 OK)
• Correct Content-Type headers
• 404 for missing files
• 403 for path traversal attempts
• 405 for non-GET methods
• Root path serves index.html

Example Static Files

• index.html - Demo homepage with modern design
• styles.css - Professional gradient styling
• app.js - JavaScript functionality demo

File Structure

src/main/java/org/juv25d/handler/
├── MimeTypeResolver.java          (67 lines)
└── StaticFileHandler.java         (198 lines)

src/main/resources/static/
├── index.html                      (40 lines)
├── css/
│   └── styles.css                  (125 lines)
└── js/
    └── app.js                      (10 lines)

src/test/java/org/juv25d/handler/
├── MimeTypeResolverTest.java      (88 lines)
└── StaticFileHandlerTest.java     (147 lines)

Integration Status

⏸️ Not yet integrated with Server/ConnectionHandler

This PR contains all core logic but avoids modifying
Server/SocketServer/ConnectionHandler to prevent conflicts with PR #28.

Integration Plan (after PR #28 merges):

1. Rebase this branch on main
2. Add integration code in ConnectionHandler:

if (request.method().equalsIgnoreCase("GET")) {
    HttpResponse response = StaticFileHandler.handle(request);
    HttpResponseWriter.write(socket.getOutputStream(), response);
}

3. Request final review
4. Merge

Architecture

Architecture decisions documented in ADR-001 (see PR #7 ).

Dependencies

• Depends on: PR Bump org.mockito:mockito-junit-jupiter from 5.21.0 to 5.22.0 in the maven-deps group #28 (Server refactoring with ConnectionHandler)
• Documented in: ADR-001 (static file serving architecture)
• Related to: Issue Add Filter for measuring request response time #18

Review Focus

1. Security validation logic - Is path traversal prevention robust?
2. MIME type mappings - Are common file types covered?
3. Test coverage - Are edge cases properly tested?
4. Code quality - Clear naming and documentation?
5. Architecture - Does it follow ADR-001 decisions?

Notes

• Static files will be bundled in JAR (SpringBoot style)
• Currently returns 405 for POST/PUT/DELETE (only GET supported)
• 404 error page includes styled HTML response
• Logging integrated with existing ServerLogging class

Summary by CodeRabbit

• New Features

  • HTTP server with request parsing and response handling
  • Docker containerization for deployment
  • Automated CI/CD pipelines for testing and container image publishing

• Tests

  • Added HTTP response tests

• Chores

  • Configured project build infrastructure and code quality tools

[coderabbitai]

Caution

Review failed

The pull request is closed.

📝 Walkthrough

Walkthrough

This PR establishes a complete Java HTTP server project. It renames the project from org.example/JavaTemplate to org.juv25d/JavaHttpServer, adds Maven wrapper scripts and Docker support, implements core HTTP handling with request parsing and response writing, configures CI/CD workflows, and introduces code formatting and mutation testing tools.

Changes

Cohort / File(s)	Summary
Build Configuration & Tooling .editorconfig, .mvn/wrapper/maven-wrapper.properties, .github/workflows/ci.yml, .github/workflows/docker-release.yml, Dockerfile, mvnw, mvnw.cmd, pom.xml	Adds project-wide style rules, Maven wrapper configuration, GitHub Actions workflows for CI and Docker image publishing, multi-stage Dockerfile for Java 25 builds, Maven wrapper startup scripts (POSIX and Windows), and updates pom.xml with new project coordinates (org.juv25d/JavaHttpServer), Java 25 target, and new plugins for code formatting (Spotless) and mutation testing (Pitest).
Core HTTP Server Implementation src/main/java/org/juv25d/App.java, src/main/java/org/juv25d/SocketServer.java, src/main/java/org/juv25d/parser/HttpParser.java, src/main/java/org/juv25d/logging/ServerLogging.java	Implements HTTP server infrastructure: SocketServer accepts connections on port 3000 and dispatches to virtual threads; HttpParser parses HTTP requests with request line, headers, and optional body validation; ServerLogging provides centralized logger configuration; App.main() invokes SocketServer.createSocket().
HTTP Request & Response Models src/main/java/org/juv25d/HttpRequest.java, src/main/java/org/juv25d/http/HttpResponse.java, src/main/java/org/juv25d/http/HttpResponseWriter.java	Introduces immutable data carriers: HttpRequest record encapsulates method, path, query, version, headers, and body; HttpResponse class encapsulates status code, text, headers, and body with defensive copies; HttpResponseWriter utility serializes HttpResponse to OutputStream with proper status line, headers, and Content-Length calculation.
Handler Skeletons & Test Stubs src/main/java/org/juv25d/handler/MimeTypeResolver.java, src/main/java/org/juv25d/handler/StaticFileHandler.java, src/test/java/org/juv25d/handler/MimeTypeResolverTest.java, src/test/java/org/juv25d/handler/StaticFileHandlerTest.java	Adds empty handler classes and test stubs for future static file and MIME type handling.
Test Updates & New Tests src/test/java/org/juv25d/AppIT.java, src/test/java/org/juv25d/AppTest.java, src/test/java/org/juv25d/http/HttpResponseWriterTest.java	Updates existing tests to new org.juv25d package; adds HttpResponseWriterTest with assertions for 200 OK and 404 Not Found response formatting.

Sequence Diagram

sequenceDiagram
    participant Client
    participant SocketServer
    participant HttpParser
    participant App
    
    Client->>SocketServer: TCP connect to port 3000
    SocketServer->>SocketServer: Accept connection
    SocketServer->>SocketServer: Spawn virtual thread
    SocketServer->>HttpParser: new HttpParser()
    Client->>HttpParser: Send HTTP request bytes
    HttpParser->>HttpParser: readLine() request line
    HttpParser->>HttpParser: Parse method, path, version
    HttpParser->>HttpParser: readLine() headers until blank
    HttpParser->>HttpParser: Parse Content-Length if present
    HttpParser->>HttpParser: Read body bytes
    HttpParser->>SocketServer: Return HttpRequest
    SocketServer->>SocketServer: Log method & path
    SocketServer->>Client: (connection remains open)

Loading

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 A server springs to life with care,
Request lines parsed through the air,
Java threads hop and bound so free,
HTTP responses flowing, just you see! ✨
From socket to response, a hop and a leap,
This rabbit's proud—the code runs deep.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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