Instead of exporting the callbacks unconditionally, why not use EXPORT_OK? Then you would have to explicitly name then in the use declaration, but I believe it may solve your problem of calling package local subroutines from the callbacks.

I.e., instead of this:

package main;
use webdav;

# ...

package webdav;
require Exporter;
@ISA = qw(Exporter);

@EXPORT = qw( get_content ...);            # replace this
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use this:

# same as above

@EXPORT_OK = qw( get_content ...);         # with this
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And then use this in your using code:

use webdav qw( get_content ...);
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Perhaps a better solution is to explicitly prefix your coderefs with the package name they live in.

dmm

If you GIVE a man a fish you feed him for a day
But, TEACH him to fish and you feed him for a lifetime