How to retrieve error details inside the on-error clause

RouterOS Scripting
1

When using the on-error clause for a /tool fetch command (or other) is it possible to get the actual error message or number ?

There must be some info available because when failing in the terminal there usually is a message saying what went wrong.
For example:
[admin@router] > /tool fetch url=htt://bad.protocol.com
failure: invalid URL protocol

The question is how can I get this message inside the on-error clause.

2

As far as I have seen you can use on-error for two things.

  1. Prevent script from stop running if there are one or more error.
  2. Run an alternate code if some error occurs.

I have not seen any possibility to get the actual error listed.
That would be nice to have, so if MT reads this, please add.

3

THE CORRECT WAY IS SANITIZE THE STRING FIRST…

for example:

:if ($theurlstring~"^(http|https|ftp|sftp|tftp)://") do={
    # something
} else={
    # do nothing
}

then you can use this example to intercept fetch errors:
http://forum.mikrotik.com/t/fetch-capable-of-following-redirects/151723/1

4

The question is about getting the on-error detailed info.
The bad URL is just an example that generates an error.

5

As far as I know this is not possible.
MikroTik knows about this and they consider implementing, but that has not yet happened.