No content-type on no body response code

[juliens]

This PR addresses an issue where the Content-Type was being automatically detected and set, even for responses that are not allowed to have a body (e.g., status codes 204 No Content, 304 Not Modified, etc.).

Summary by CodeRabbit

• New Features

  • Introduced a function to determine if a response status code allows for a body, enhancing response handling based on HTTP standards.

• Bug Fixes

  • Updated response handling to ensure the Content-Type header is absent for 204 No Content status responses.

• Tests

  • Added a test to verify that no Content-Type header is sent for 204 No Content responses, ensuring compliance with HTTP specifications.

[coderabbitai]

📝 Walkthrough

📝 Walkthrough

Walkthrough

The changes introduce a new function, bodyAllowedForStatus, that determines if an HTTP response status code permits a body according to RFC 7230. This function is integrated into the Close method of the GzipResponseWriter struct to conditionally check the response status before setting the Content-Type header. Additionally, a new test function is added to ensure that the Content-Type header is absent for 204 No Content responses, along with minor formatting adjustments in existing tests.

Changes

File	Change Summary
gzhttp/compress.go	Added bodyAllowedForStatus(status int) bool function to check if a body is allowed for a status code. Modified Close method in GzipResponseWriter to use this function for setting Content-Type.
gzhttp/compress_test.go	Added TestNoContentTypeWhenNoContent(t *testing.T) to verify absence of Content-Type for 204 No Content. Minor formatting change in TestFlushAfterWrite3.

Sequence Diagram(s)

sequenceDiagram
    participant Client
    participant Server
    participant GzipResponseWriter

    Client->>Server: Request
    Server->>GzipResponseWriter: Write response
    GzipResponseWriter->>GzipResponseWriter: Check status code
    alt Body allowed
        GzipResponseWriter->>GzipResponseWriter: Set Content-Type
    else No body allowed
        GzipResponseWriter->>GzipResponseWriter: Do not set Content-Type
    end
    GzipResponseWriter->>Server: Close response
    Server->>Client: Send response

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📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL

📥 Commits

Files that changed from the base of the PR and between 6d73e43 and 71a1e13.

📒 Files selected for processing (1)

• gzhttp/compress.go (2 hunks)

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

• gzhttp/compress.go

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[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: CodeRabbit UI
Review profile: CHILL

📥 Commits

Files that changed from the base of the PR and between 13a1ce6 and 6d73e43.

📒 Files selected for processing (2)

• gzhttp/compress.go (2 hunks)
• gzhttp/compress_test.go (2 hunks)

🔇 Additional comments (3)

gzhttp/compress.go (2)

327-339: LGTM: Well-implemented function following RFC 7230

The bodyAllowedForStatus function is a great addition. It correctly implements the rules specified in RFC 7230, section 3.3, for determining whether a response body is allowed for a given HTTP status code. The function is concise, easy to understand, and follows best practices.

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352-352: Excellent improvement in Content-Type handling

This change significantly improves the handling of responses without bodies. By using the bodyAllowedForStatus function, the code now correctly determines whether to set the Content-Type header based on the response status code. This ensures compliance with HTTP specifications and resolves the issue of setting Content-Type headers for responses that should not have a body (e.g., 204 No Content, 304 Not Modified).

The modification aligns perfectly with the PR objectives and enhances the overall correctness of the response handling mechanism.

gzhttp/compress_test.go (1)

1601-1618: LGTM! Important test case added.

This new test function TestNoContentTypeWhenNoContent is a valuable addition. It ensures that the gzip middleware correctly handles responses with HTTP 204 No Content status, specifically checking that no Content-Type header is set. This adheres to HTTP specifications and covers an important edge case.

[klauspost]

Let's keep the internal part as-is, but skip setting the header on these types.

[klauspost]

Thanks for the contribution!