Perl to convert data into JSON format

Question

I have a problem, converting my data into json, and I don't know why.

Here is some Code that works:

#constructor
sub new {
  my $class = shift;
  my $Titel = shift;
  my $Text = shift;
  my $Time = localtime;
  my $self = {};

  $self->{text} = $Text;
  $self->{create} = $Time;
  $self->{edit} = $Time;

  my $json = JSON::XS->new();

  open WF, '>> $file' || die "Error : $!";
  print WF $json->encode($self)."\n";
  close WF;

  bless $self, $class;
}

I create an 'object' and save the data in a textfile (via JSON), too.

I have problems, if I try to edit some data:

sub edit {
my $self = shift;
my $Text = shift;
my $ID = shift;
my $Time = localtime;
my $json = JSON::XS->new();
$json->allow_blessed(1);

$self->{text} = $Text; #edit text
$self->{edit} = $Time; # edit date

open INPUT, '< $file' || die "Error : $!";
my @data = <INPUT>;
close(INPUT);

open WF, '> $file' || die "Error : $!";

for (my $Count=0; $Count<=$#data; $Count++){
    chomp($data[$Count]);

    if($Count == $ID){#if line of data found, who is going to be edited
        print WF $json->encode($self)."\n";
    }else{
        print WF $data[$Count]."\n";
    }
}

close WF;
}

What I try to do is to edit just one line in the textfile.. (if you have a better idea, please show me :D)

I see no difference between my procedure in the code shown first and that one....

it just writes "null" back in the textfile...

Any ideas?

Answer 1

I'm no JSON expert, but the encode method is having trouble with a blessed reference. Using an unblessed reference seems like a valid workaround:

if($Count == $ID){#if line of data found, who is going to be edited
    print WF $json->encode( {%$self} )."\n";
...

Answer 2

I second the notion (as you have already found) that the problem is the blessed reference, however I offer you another solution (the is Perl after all: TIMTOWTDI). The Acme::Damn module allows you to unbless (i.e. damn) an object. Therefore you should be able to:

print WF $json->encode(damn($self))."\n";

Also I felt I had to share, since the method is so cleverly named.