On Fri, 31 Oct 2025 10:12:27 GMT, Peyang <[email protected]> wrote:

>> Hi all,
>> 
>> [JEP 408](https://openjdk.org/jeps/408) introduced the Simple Web Server in 
>> Java 18, providing a minimal webserver for serving static files over HTTP.
>> 
>> [RFC 9110](https://www.rfc-editor.org/rfc/rfc9110.html#name-range-requests) 
>> defines "Range Requests" as an optional feature that allows clients to 
>> request a subset of a resource's content. Supporting Range requests in the 
>> context of JDK's Simple Web Server means enabling the server to serve only 
>> the requested portion of a static file.
>> 
>> This change contains:
>> 
>> 1. Enhances `sun.net.httpserver.simpleserver.FileServerHandler` in the 
>> `jdk.httpserver` module to support `Range` and `If-Range` headers.
>> 2. Calculates an `ETag` for each resource based on its last-modified date 
>> and file size and sends it to the client on demand for use with the 
>> `If-Range` header.
>> 3. Returns the `Accept-Ranges` header for all file retrievals, and 
>> `Content-Range` when a client requests a specific range.
>> 4. Adds a new constant `HTTP_RANGE_NOT_SATISFIABLE` to the `Codes` class to 
>> indicate invalid ranges.
>> 5. Returns `206 Partial Content` for valid ranges and `416 Range Not 
>> Satisfiable` for invalid ranges.
>> 6. Includes corresponding tests to verify correct behavior.
>> 
>> This enhancement was motivated by recent discussions on the net-dev mailing 
>> list, which requested support for Range requests along with example use 
>> cases: https://mail.openjdk.org/pipermail/net-dev/2025-April/026364.html
>> It was also discussed briefly on the net-dev mailing list: 
>> https://mail.openjdk.org/pipermail/net-dev/2025-October/028586.html
>
> Peyang has updated the pull request incrementally with one additional commit 
> since the last revision:
> 
>   Add documentation for HTTP range requests support in SimpleFileServer

src/jdk.httpserver/share/classes/sun/net/httpserver/simpleserver/FileServerHandler.java
 line 310:

> 308:             return true;
> 309:         }
> 310:         servePartialContents(exchange, path, ranges);

The RFC says:

> A server that supports range requests MAY ignore or reject a 
> [Range](https://www.rfc-editor.org/rfc/rfc9110.html#field.range) header field 
> that contains an invalid 
> [ranges-specifier](https://www.rfc-editor.org/rfc/rfc9110.html#rule.ranges-specifier)
>  ([Section 
> 14.1.1](https://www.rfc-editor.org/rfc/rfc9110.html#range.specifiers)), a 
> [ranges-specifier](https://www.rfc-editor.org/rfc/rfc9110.html#rule.ranges-specifier)
>  with more than two overlapping ranges, or a set of many small ranges that 
> are not listed in ascending order, since these are indications of either a 
> broken client or a deliberate denial-of-service attack ([Section 
> 17.15](https://www.rfc-editor.org/rfc/rfc9110.html#overlapping.ranges)).

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

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/28021#discussion_r2481206652

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