RFR: 8355572: Support HTTP Range requests in Simple Web Server [v3]

[Peyang]

On Fri, 31 Oct 2025 11:23:49 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

>> Hello @dfuch,
>> 
>> Thank you for the review. I have completed all the requested changes: formatting fixes, additional unit tests, and updates to the JavaDoc of `SimpleFileServer`.
>> 
>> Regarding the CSR, I am not listed in the Census and therefore do not have a JBS/OpenJDK account to proceed with it.
>> Would it be possible for you to either issue an account for me or handle the CSR on your side?
>> If either option works, I can provide the necessary information, including the full text for the CSR ticket.
>> 
>> Thank you very much for your understanding.
>
>> Regarding the CSR, I am not listed in the Census and therefore do not have a JBS/OpenJDK account to proceed with it.
> 
> No problem - one of us will create the CSR, when we have setlled on the documentation and implementation changes and the PR is approved or close to be approved.

Thanks @dfuch, @fandreuz, @Michael-Mc-Mahon and @efge for the detailed reviews.
Since the discussion has become quite long, here’s a summary of the feedback and how it was addressed.

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#### @dfuch

> ETag is an entirely separate feature from Range and should be in its own separate follow-up Jira ticket and PR.

-> Removed ETag-related code and tests in a separate commit.

> Support for Range header will need to be documented in `SimpleFileServer.java`.

-> Updated the documentation to mention HTTP Range request support.

> I would expect a validation of the ranges list before we serve them. 

->  Implemented range list normalization: overlapping or unsorted ranges are merged and sorted before returning, following [RFC 9110 §15.3.7.2](https://www.rfc-editor.org/rfc/rfc9110.html#section-15.3.7.2-3).


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#### @Michael-Mc-Mahon

> We probably should send the `Accept-Ranges` header in response to a HEAD request also.

-> Confirmed that `Accept-Ranges` is already included for HEAD requests.

> Do we need to support `If-Range` with this PR? … It seems like it belongs more with a general conditional-requests feature.  

-> Removed the initial `If-Range` + ETag handling; this will be covered by a future follow-up.

> Is this not an error situation, if we reach EOF and have only partially returned the requested range?

-> Updated the implementation to throw an `EOFException` and close the connection when EOF is reached before completing the requested range.

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#### General

> General comments about formatting and tests  

->  Fixed formatting, added more tests, and improved range header parsing and validation (ensuring ranges are sorted and merged if overlapping).

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### Still open

- CSR creation/approval (maintainer side)  
- Clarify whether `If-Range` will remain partial (Last-Modified based) or gain full ETag support later  
- Final review of the range-merging logic and corresponding tests

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PR Comment: https://git.openjdk.org/jdk/pull/28021#issuecomment-3496435676