Re: [sage-support] CORS issue with sagecell.sagemath.org/service

[Dima Pasechnik]

On Tue, Jan 6, 2026 at 9:26 PM Jeremy Sylvestre <jsyl...@ualberta.ca> wrote:
>
> Hi there, I've got some code that I haven't used for a couple of years that used to work with
>
> sagecell.sagemath.org/service

this URL is not working, but

https://sagecell.sagemath.org/

is fine.

>
> but now is failing with
>
> Access to XMLHttpRequest at 'https://sagecell.sagemath.org/service' from origin 'https://sites.ualberta.ca' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
>
> Is this service no longer supported?
>
> Thanks,
> Jeremy Sylvestre
> University of Alberta, Augustana Campus
>
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[Dima Pasechnik]

---------- Forwarded message ---------
From: Jeremy Sylvestre <jsyl...@ualberta.ca>
Date: Tue, Jan 6, 2026 at 9:26 PM
Subject: [sage-support] CORS issue with sagecell.sagemath.org/service
To: sage-support <sage-s...@googlegroups.com>


Hi there, I've got some code that I haven't used for a couple of years
that used to work with

sagecell.sagemath.org/service

[Andrey Novoseltsev]

/service was "overused" and is now blocked on public servers...

[Paul Masson]

Could you please be more specific as to what “overused” means here? Did one particular IP address use excessive bandwidth or more than one? And where exactly did you make the change to block the service: on Github or other publicly available location, or just by private fiat?

I personally have a few web pages that illustrate how to use the service in principle, but have not used them extensively since I have JavaScript libraries to provide my principal needs. Still, I really dislike when a page fails to function through no fault of my own. Was there ever a public discussion concerning blocking this basic service?

[Andrey Novoseltsev]

Overused means that public servers became unavailable. When a situation like this happens, I do my best to come up with a reasonable solution. That solution likely means that some portion of services becomes unavailable (like internet access before), but the rest continues to function. The implementation may or may not be publicly visible.

If it affects some users negatively and they complain, I can try to make further adjustments but without any guarantees. One is always welcome to spin up a personal server with any desired restrictions or their absence!

[Paul Masson]

I would appreciate additional clarification:

1) Did /service stop working completely or just become sluggish? Did this spill over into other server functionality?

2) Was there truly no way of identifying those responsible for this behavior and blocking just them, so that the rest of us have at least some limited access?

3) Was there ever a public discussion of this situation, or did you make the change by personal fiat?

Thank you. 

[Dima Pasechnik]

It's a best effort service. There is no funding, as far as I know.
It's hard enough to lock down the service like that so that it's not used for all sorts of activities which have nothing to do with running small Sage scripts.