readdir() attempted on invalid dirhandle - perl

Question

What am I doing wrong? I've tried many things but can't seem to read from this file. Thanks!
my $d = 'URLs.txt';
open(my $fh, '<:encoding(UTF-8)', $d)
#opendir(D, "$d") || die "Can't open directory $d: $!\n";
or die "Can't open directory $d: $!\n";
my #list = readdir($fh);
closedir($fh);
foreach my $f (#list) {
my $json_data = get "$f";
my $json_obj = new JSON;
my $URLdata = $json_obj->decode($json_data);
return $URLdata->{'status'} eq 'UP';
}

Answer 1

URLs.txt appears to be a file, not a directory
To open a file, write
open my $fh, '<', $filename or die $!;
and read from it with
while ( my $line = <$fh> ) { ... }
To open a directory, write
opendir my $dh, $dirname or die $!;
and read its contents with
while ( my $item = readdir $dh ) { ... }
If you had use strict and use warnings 'all' in place as you should in every Perl program you write you would have seen
readdir() attempted on invalid dirhandle $fh
closedir() attempted on invalid dirhandle $fh
which would have guided you towards the problem
You may be better of with other functions, depending on what it is you want to do

Answer 2

Your variable names are not great, to put it mildly. Let's fix that!
use strict;
use warnings;
use JSON;
use LWP::Simple;
my $file = 'URLs.txt';
open(my $fh, '<:encoding(UTF-8)', $file) or die "Can't open file $file: $!\n";
chomp(my #lines = <$fh>);
close($fh);
foreach my $url (#lines) {
my $json_text = get($url);
if (defined($json_text)) {
my $perl_ref = decode_json($json_text);
if ($perl_ref->{status} eq 'UP') {
print "foo\n";
}
} else {
# handle the error!
}
}
You'll notice I also:
Added use strict and use warnings, which should be in every Perl file you write
Added error-checking to the LWP get() result
Removed indirect object notation (new JSON) in favor of the decode_json() convenience function. It's the same as JSON->new->utf8->decode(), only shorter.
Removed the return statement, because it doesn't make any sense outside of a subroutine. If this code has actually been yanked from a subroutine, then you should show that as part of your MCVE.