Iterate through values of a HASH and convert to comma separated strings - perl

Question

I want to iterate through the values of a big hash, and if any of the values of that hash are keys, I want to convert it into a comma separated list which can be parsed in 'query_form'.
Right now from the data below I have:
name=Bob&surname=Whitbread&customerErrors=HASH(Xa456) (for example)
Here's what I have so far:
sub convertArgsToQueryString {
my $class = shift;
my $args = shift;
return unless ($args && ref($args) eq 'HASH');
foreach my $key (values %$args) {
if (ref($key) eq 'HASH') {
# change to a comma separated list
}
}
my $dummyURL = URI->new('', 'http');
$dummyURL->query_form(%$args);
return $dummyURL->query;
}
Data:
my $data = {
'name' => 'Bob',
'surname' => 'Whitbread',
'customerErrors' => {
'error1' => 'paymentError',
'error2' => 'addressError'
},
};
Query Form:
name=Bob&surname=Whitbread&customerErrors=paymentError,addressError

Answer 1

This will do what you want
print join ",", values %{$data->{customerErrors}},"\n";
Although I would suggest, rather than error1 as hash keys, you'd be better off with an array:
my $data = {
'name' => 'Bob',
'surname' => 'Whitbread',
'customerErrors' => [ 'paymentError', 'addressError' ],
};
Scaling that out to be generic, you will find the ref function to be helpful:
foreach my $key ( keys %$data ) {
print "$key is a ", ref $data->{$key},"\n";
if ( ref $data->{$key} eq 'HASH' ) {
print join ",", values %{$data->{$key}};
}
else {
print $data -> {$key},"\n";
}
}
Or tersely:
print join "\&", map { #join iterated on &
join "=", $_, #join paired values on =
ref $data->{$_} eq 'HASH' #ternary to check reference type
? values %{ $data->{$_} } #extract values if HASH
: $data->{$_} #extract just value if not.
} keys %$data; #iterate keys of data
Which gives as output:
name=Bob&customerErrors=addressError=paymentError&surname=Whitbread