I tried to determine the existence of a file on the internet. See the following macro call:

        % Test if file exists.
        \edef\theurl{\linkprotocol://\urlbase\xmlatt{#1}{link}\thesuffix}
        \doiffileelse
        	{\theurl}
        	{\verbose{HVDM-PEV-TEST}{file exists: \theurl}}
        	{\verbose{HVDM-PEV-TEST}{file does not exist: \theurl}}

It seems that \doiffileelse always results in true except for local files where nonexistence is correctly handled.

For example the following url definitely does not exist but nevertheless \doiffileelse reports its existence:
HVDM-PEV-TEST   > file exists: http://hansvandermeer.myqnapcloud.com/archive/denhaag/hga-dtb-1869-6040.pdf

Is it possible that the \doiffile macros are extended for files on the internet or a correponding set \doifurl is developed?

Hans van der Meer