Issue #109: Add HTTP HEAD support

[mikee13d]

This PR adds support for the HTTP HEAD method. HEAD requests now return the same status code and headers as GET requests, but without a response body. Existing GET functionality remains unchanged, and error responses follow the same behavior.

Summary by CodeRabbit

• Bug Fixes
  • Properly support HTTP HEAD requests: responses now include correct headers and content-length but omit the response body, improving protocol behavior while preserving existing GET responses.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 158230da-f6b4-478d-b7d2-32cdc53062d0

📥 Commits

Reviewing files that changed from the base of the PR and between f1b7d1f and 6b769e5.

📒 Files selected for processing (1)

• src/main/java/org/example/StaticFileHandler.java

🚧 Files skipped from review as they are similar to previous changes (1)

• src/main/java/org/example/StaticFileHandler.java

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📝 Walkthrough

Walkthrough

ConnectionHandler now dispatches HEAD requests to a new StaticFileHandler.sendHeadRequest(...); other methods continue to use sendGetRequest(...). sendHeadRequest builds headers (including Content-Length) but writes an empty body per HTTP HEAD semantics.

Changes

Cohort / File(s)	Summary
Request routing logic src/main/java/org/example/ConnectionHandler.java	Add conditional: if request.getMethod() is HEAD (case-insensitive) call sendHeadRequest(outputStream, uri), otherwise call existing sendGetRequest(...). No other control-flow or public API changes.
HEAD request handler src/main/java/org/example/StaticFileHandler.java	Add public sendHeadRequest(OutputStream outputStream, String uri) that reuses handleGetRequest(uri) to determine status, headers and Content-Length, then writes headers with an empty body (new byte[0]) and flushes.

Sequence Diagram

sequenceDiagram
    actor Client
    participant ConnectionHandler
    participant StaticFileHandler

    Client->>ConnectionHandler: HTTP HEAD /file.txt
    ConnectionHandler->>ConnectionHandler: Evaluate request.getMethod()
    alt Method is HEAD
        ConnectionHandler->>StaticFileHandler: sendHeadRequest(outputStream, uri)
        StaticFileHandler->>StaticFileHandler: handleGetRequest(uri)
        StaticFileHandler->>StaticFileHandler: Build response headers (incl. Content-Length)
        StaticFileHandler-->>Client: Send headers only (empty body)
    else Method is GET (or other)
        ConnectionHandler->>StaticFileHandler: sendGetRequest(outputStream, uri)
        StaticFileHandler->>StaticFileHandler: handleGetRequest(uri)
        StaticFileHandler->>StaticFileHandler: Build headers + body
        StaticFileHandler-->>Client: Send headers + file content
    end

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Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 A quiet hop, a header's song,
I counted bytes — but not for long.
I send the signs, the tale's complete,
No heavy load upon my feet.
Head first, body rests — hooray! 🎉

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Issue #109: Add HTTP HEAD support' directly and clearly describes the main change: adding HTTP HEAD method support, which matches the changeset that implements HEAD request handling in ConnectionHandler and StaticFileHandler.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feature/109-support-http-head

⚔️ Resolve merge conflicts

• Resolve merge conflict in branch feature/109-support-http-head

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@src/main/java/org/example/StaticFileHandler.java`:
- Around line 69-78: sendHeadRequest currently calls handleGetRequest(uri) then
sets an empty body, which makes HttpResponseBuilder compute Content-Length: 0;
instead, after handleGetRequest(uri) use the computed fileBytes length to set
the Content-Length header on the HttpResponseBuilder before suppressing the body
(e.g., response.setHeader("Content-Length", String.valueOf(fileBytes.length)) or
response.setContentLength(fileBytes.length) if available), then
setStatusCode(statusCode), setContentTypeFromFilename(uri), setBody(new byte[0])
and write the response so the HEAD response advertises the same Content-Length a
GET would return.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 0c570eff-f22f-459f-9997-b391714ab6f0

📥 Commits

Reviewing files that changed from the base of the PR and between c473d5b and f1b7d1f.

📒 Files selected for processing (2)

• src/main/java/org/example/ConnectionHandler.java
• src/main/java/org/example/StaticFileHandler.java