If you really want to reinvent the wheel, you can read the query string as follows: 

my $query;
my $req_method = $ENV{REQUEST_METHOD};
    
if ($req_method eq 'POST') {
    read STDIN, $query, $ENV{CONTENT_LENGTH};     # <--
} elsif ($req_method eq 'GET') {
    $query = $ENV{QUERY_STRING};
}

[download]

(But it's not recommended...)

In reply to Re: STDIN not working, STDIN hanging by almut
in thread STDIN not working, STDIN hanging by FRIENDOFGOD

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