[tz] Data loss on FTP Server

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Tue Oct 24 23:12:37 UTC 2017

On 2017-10-24 16:26, Zefram wrote:
> Paul Eggert wrote:
>> I no longer recommend FTP to get tzdb.
> HTTPS is fine for retrieving a specific release, but FTP offers a couple
> of other facilities that AFAICS HTTPS doesn't provide.  Specifically, by
> FTP I can enumerate old releases (NLST on the /tz/releases directory), and
> I can identify the latest release (by processing the directory listing).
> I've automated those jobs.  Is there a recommended way to do these things
> through the HTTPS interface?  (Scraping a human-oriented web page isn't
> an attractive approach.)

I've used the FTP site to date because I can download the -latest symlinks as
files using wget -N to a cache directory, so it only checks the mod date if
unchanged, then run readlink on the symlink files to get the actual version
filenames, and quit if those are the same as the last downloaded.

If the HTTPS repository/releases/ were browsable and/or had public static
-latest URIs provided by either server or HTML redirection, I could do similar
using curl sans -L to get the latest version URIs, compare those to the last
downloaded, and quit if unchanged.

I do prefer HTTPS where available, preferably also backed up by directories with
decent sha###sums, and/or gpg/pgp .sigs, and/or .ascs, for downloaded file
validation, in case of server, storage, or site problems.

Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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