[R] file.access returning -1 for a file on remote Windows drive.

[Jeff Newmiller]

I don't know.

Windows uses Access Control Lists, while POSIX (e.g. Linux) uses user/group/other classification. These two world views do not have a simple 1:1 correspondence, so you might see some difference between your file security configuration in the file properties.

Then again there are some hints online that the problem is not new... there is a package called R.utils that may help.


On February 28, 2020 2:53:49 PM PST, Sam Albers <tonightsthenight using gmail.com> wrote:
>Thanks Jeff. I am probably not explaining myself very well but my
>question under what circumstances would
>
>summary(file(remote_file, "rb"))$`can read`
>
>be different from:
>
>file.access(remote_file, 4)
>
>If my permissions were different across remote and local should that
>not be reflected in both of these functions?
>
>On Fri, Feb 28, 2020 at 2:37 PM Jeff Newmiller
><jdnewmil using dcn.davis.ca.us> wrote:
>>
>> Dunno. They agree for me. Maybe look closer at all permissions via
>Windows File Manager?
>>
>> On February 28, 2020 2:06:34 PM PST, Sam Albers
><tonightsthenight using gmail.com> wrote:
>> >Some additional follow-up:
>> >
>> >> summary(file(remote_file, "rb"))$`can read`
>> >[1] "yes"
>> >
>> >> summary(file(local_file, "rb"))$`can read`
>> >[1] "yes"
>> >
>> >compared to:
>> >
>> >> file.access(local_file, 4)
>> >local.R
>> >         0
>> >
>> >> file.access(remote_file, 4)
>> >remote.R
>> >            -1
>> >
>> >Can anyone think why file.access and file would be contradicting
>each
>> >other?
>> >
>> >Sam
>> >
>> >On Fri, Feb 28, 2020 at 10:47 AM Sam Albers
>> ><tonightsthenight using gmail.com> wrote:
>> >>
>> >> Hi there,
>> >>
>> >> Looking for some help in diagnosing or developing a work around to
>a
>> >> problem I am having on a Windows machine. I am running R 3.6.2.
>> >>
>> >> I have two identical files, one stored locally and the other
>stored
>> >on
>> >> a network drive.
>> >>
>> >> For access:
>> >>
>> >> > file.access(local_file, 4)
>> >> local.R
>> >>          0
>> >>
>> >> > file.access(remote_file, 4)
>> >> remote.R
>> >>             -1
>> >>
>> >> Also for file.info
>> >>
>> >> > file.info(local_file)$mode:
>> >> [1] "666"
>> >>
>> >> > file.info(remote_file)$mode:
>> >> [1] "666"
>> >>
>> >> Ok so I am access issues. Maybe they are ephemeral and I can
>change
>> >> the permissions:
>> >>
>> >> > Sys.chmod('remote.R', mode = '666')
>> >> > file.access(remote_file, 4)
>> >> remote.R
>> >>             -1
>> >>
>> >> Nope. I am thoroughly stumped and maybe can't make it any further
>> >> because of Windows.
>> >>
>> >> Downstream I am trying to use digest::digest to create a hash but
>> >> digest thinks we don't have permission because file.access is
>> >failing.
>> >> Any thoughts on how I can get file.access to return 0 for the
>> >remote.R
>> >> file? Any ideas?
>> >>
>> >> Thanks in advance,
>> >>
>> >> Sam
>> >
>> >______________________________________________
>> >R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> >https://stat.ethz.ch/mailman/listinfo/r-help
>> >PLEASE do read the posting guide
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>> >and provide commented, minimal, self-contained, reproducible code.
>>
>> --
>> Sent from my phone. Please excuse my brevity.

-- 
Sent from my phone. Please excuse my brevity.