Re: home server for email box

[Greg Wooledge <greg@wooledge.org>]

On Sun, Mar 12, 2023 at 12:13:54PM +0100, Yassine Chaouche wrote:
> function net.ip.reputation(){
>     revip=$(net.ip.reverse "$1")
>     results=$(dig +short $revip.zen.spamhaus.org)
>     [[ -z $results ]] && (echo "clean"; return 0)

You're caling return inside a subshell.  This doesn't actually return
from the function, since it occurs in a child process.

unicorn:~$ f() { true && (echo true; return 0); echo problem; }
unicorn:~$ f
true
problem

You either need to use "if", or use a curly-braced command group instead
of your parenthesized subshell command.

    [[ -z $results ]] && { echo "clean"; return 0; }

It would also be polite to declare your function's local variables as
"local".

>     for result in $results

You're using 3 variables locally, so you could add

    local revip results result

at the top of the function.

Finally, you're relying on the output of "dig +short ..." to be safely
word-splittable.  I don't know whether this is always going to be true.
However, it does look like dig +short writes its output as a sequence
of items, one per line.  This means you can read them into an array
without performing word-splitting or globbing:

    mapfile -t results < <(dig +short "$revip".zen.spamhaus.org)
    if (( ${#results[@]} == 0 )); then
        echo clean
        return 0
    fi
    for result in "${results[@]}"
    do
        ...

The way you've got it *might* be OK.  I just don't know whether the
output of dig +short can ever contain internal whitespace or globbing
characters.  I'd rather not take that chance.