[R] Very odd issue getting "Input/output error" running shiny app from index.html locally but same shiny on my server working fine

[Eric Berger]

[forgot to hit reply-all]
Hi Chris,
When I have encountered similar sounding problems in the past I was able to
work around them as follows.
Instead of running rstudio locally, I run rstudio-server locally and then
in a browser I enter the URL http://localhost:8787/

HTH,
Eric


On Mon, May 19, 2025 at 6:21 PM Eric Berger <ericjberger using gmail.com> wrote:

> Hi Chris,
> When I have encountered similar sounding problems in the past I was able
> to work around them as follows.
> Instead of running rstudio locally, I run rstudio-server locally and then
> in a browser I enter the URL http://localhost:8787/
>
> HTH,
> Eric
>
> On Mon, May 19, 2025 at 6:01 PM Chris Evans via R-help <
> r-help using r-project.org> wrote:
>
>> I realise that shiny and Rstudio is often seen as OT here but I have a
>> strong suspicion that the issue is R or R/OS related so I hope someone
>> here will have some thoughts that might help me.
>>
>> The scenario is that as of yesterday running my shiny project locally
>> from within Rtudio, i.e. by opening the index.html with preview, gets me
>> "Input/output error" when I click on a link to an app.
>>
>> The same shiny running on my server (https://shiny.psyctc.org) runs
>> fine. So if I click on the link
>> https://shiny.psyctc.org/apps/COREpapers1 there then that app runs
>> fine.  However, when I do the same locally I get "Input/output error" in
>> the window that pops up where the app should run! Very bizarrely, if I
>> open the app itself locally in Rstudio it runs fine.
>>
>> I am completely baffled by this, have never seen it before and some
>> searching on the web only suggest that "Input/output error" may be an OS
>> level error and a suggestion that dmesg may give me a clue about it.
>> However,dmesg is showing nothing that looks remotely pertinent and
>> nothing new appears in rerunning dmesg immediately after invoking that
>> error message.  I have updated and rebooted the local machine (rather
>> desperate I admit) and that did update quite a lot of core linux files
>> (despite my having updated this morning say six hours ago) ... but
>> nothing new in R or R packages and the problem stayed the same.
>>
>> To make it even more confusing the server and the local machine are both
>> running R 4.5.0 (2025-04-11) and shiny version is 1.10.0 on both. I use
>> git to package the server project and that gets transferred to the
>> server from the local machine and commit is showing no local changes and
>> the last change is showing as on 5.v.25.  The project can be seen at
>> https://github.com/cpsyctc/shiny-server.
>>
>> The server is running
>>     Debian 5.10.197-1 (2023-09-29) x86_64 GNU/Linux
>> but the local machine runs
>>     Linux tuxedo-os 6.11.0-114025-tuxedo #25~24.04.1tux1 SMP
>> PREEMPT_DYNAMIC
>>
>> I would hugely appreciate it if anyone has any thoughts about this, any
>> things I might do to debug it more. It's currently getting in the way of
>> some mildly urgent work I need to do on the server (of course it is, IT
>> knows when you are vulnerable!)
>>
>> TIA,
>>
>> Chris
>>
>> --
>> Chris Evans (he/him)
>> Visiting Professor, UDLA, Quito, Ecuador
>> CORE site: http://www.coresystemtrust.org.uk
>> <https://www.coresystemtrust.org.uk/>
>> Other work web site: https://www.psyctc.org/psyctc/
>> Personal site: https://www.psyctc.org/pelerinage2016/
>> <https://ombook.psyctc.org/book>
>>
>> ______________________________________________
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>> PLEASE do read the posting guide
>> https://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>

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