Proposal: 8355572: Implement Range header support for jwebserver

[Daisuke Yamazaki]

Hello,

Thank you for your support and the helpful suggestions.

I will explore possible implementation approaches for adding Range header support.  
If I can get it working successfully, I plan to submit a Pull Request for review.

In the meantime, I will wait for any further feedbackon the proposal by anyone.

Best regards,  
D. Yamazaki


---- On Fri, 24 Oct 2025 00:11:58 +0900 Daniel Fuchs <daniel.fuchs at oracle.com> wrote ---

 > Hi, 
 >  
 > I would support investigating adding support for Range header in 
 > the FileServerHandler. 
 >  
 > In the HttpClient, we have recently added a new 
 > BodyPublishers.ofFileChannel() request publisher as a 
 > potential building block to ease implementation of 
 > partial/resumable file uploads in applications. 
 >  
 > We have nothing out of the box for resumable file downloads 
 > in the HttpClient API though. 
 >  
 > It would be good if you could use the HttpClient API 
 > in the unit tests you will develop. Maybe we could use 
 > that as an opportunity to learn whether some more building 
 > blocks of general utility could be added on the client 
 > side (in the future) to ease the implementation of applications 
 > that would have a need for Range headers, such as to implement 
 > a download manager for instance. 
 >  
 > best regards, 
 >  
 > -- daniel 
 >  
 >  
 > On 23/10/2025 15:49, Daisuke Yamazaki wrote: 
 > > Thank you for the clarification and context. 
 > > 
 > > I understand that there is a legitimate need for Range header support. 
 > > However, whether such a feature is necessary for the simple jwebserver is 
 > > still open for discussion. 
 > > 
 > > Nevertheless, while the benefits are clear, I do not see any significant 
 > > drawbacks apart from potential maintainability or slight code growth. 
 > > I personally think it would be reasonable to implement this feature. 
 > > 
 > > I plan to wait for a bit to allow further discussion, and if no objections 
 > > arise, I intend to proceed with the implementation. 
 > > 
 > > ---- On Thu, 23 Oct 2025 02:56:29 +0900 Ethan McCue <ethan at mccue.dev> wrote --- 
 > > 
 > >   > Adding for context that there are legitimate usages for this that are within the jdk httpserver's remit of jwebserver and educational purposes. Cheerpj would let a student run their java code in a browser and requires range headers support. 
 > >   > 
 > >   > On Wed, Oct 22, 2025, 7:23 AM Daisuke Yamazaki <d.yamazaki at peya.tokyo> wrote: 
 > >   > 
 > >   > Hello all, 
 > >   > 
 > >   >  I would like to work on implementing Range header support for jwebserver, 
 > >   >  related to JDK-8355572. 
 > >   >  Before I start working on it, i'd like to confirm whether it's okay for me to 
 > >   >  take this issue. 
 > >   > 
 > >   >  Here's my current design idea: 
 > >   > 
 > >   >  1. Introduce a RangeEntry record inside FileServerHandler to represent 
 > >   >  each requested range 
 > >   >  2. In FileServerHandler.serveFile(), detect the Range header and parse it into 
 > >   >   a list of RangeEntry objects. 
 > >   >    If parsing fails or the range is invalid, return 416 Range Not Satisfiable. 
 > >   >  3. If multiple ranges are specified, generate a random boundary 
 > >   >  string and return a multipart/byteranges response. 
 > >   > 
 > >   >  Please let me know if it’s okay for me to proceed with this implementation, 
 > >   >  or if there are any design points I should consider before starting. 
 > >   > 
 > >   >  Thanks, 
 > >   >  D. Yamazak 
 > >   > 
 > > 
 >  
 >