[Dancer-users] Follow-up: extending the serializer

7 Jun 2011

      On Jun 7, 2011, at 4:51 PM, Mr. Puneet Kishor wrote:
...
I am trying to write a new serializer plugin called `Dancer::Serializer::Tgz` modeled after Data::Dumper, JSON, etc. The idea is that, in conjunction with `Dancer::Plugin::REST` and `Dancer::Serializer::Mutable`, the user would be able to request data in .tgz format on demand like so --
$ curl http://example.com/employees.tgz
Here is my baby code, and it gives me a rather unhelpful "an internal error occurred". What am I doing wrong?
After much fiddling, I was able to see the following errors --

in my Apache error log, I get

Deep recursion on subroutine "Dancer::Error::render" at ../Dancer.pm line 312.
Deep recursion on subroutine "Dancer::Error::_render_serialized" at ../Dancer/Error.pm line 167.
Deep recursion on subroutine "Dancer::Serializer::Tgz::serialize" at ../Dancer/Error.pm line 177.
Deep recursion on subroutine "Dancer::_send_file" ../Dancer.pm line 140.

If I uncomment the `sub content_type {'application/gzip'}` I also get 

Subroutine content_type redefined at ../Dancer/Serializer/Tgz.pm line 43.

Also, if I comment the `send_file` command in serialize(), I actually do get a result.tgz. If I untar that result.tgz, I see the following text

{
   "error" : "Serializer (Dancer::Serializer::Tgz) failed at serializing Dancer::Error=HASH(0x100a93008):\nencountered object 'Dancer::Error=HASH(0x100a93008)', but neither allow_blessed nor convert_blessed settings are enabled at (eval 71) line 153.\n"
}

What am I doing wrong?
...
Note: in this case, only the serializer (downloading data) makes sense; the deserializer doesn't make any sense.
-----
package Dancer::Serializer::Tgz;
use strict;
use warnings;
use Carp;
use Dancer ':syntax';
use Archive::Tar;
use base 'Dancer::Serializer::Abstract';
# helpers
sub from_tgz {
   my ($string) = @_;
   my $s = Dancer::Serializer::Tgz->new;
   $s->deserialize($string);
}
sub to_tgz {
   my ($data) = @_;
   my $s = Dancer::Serializer::Tgz->new;
   $s->serialize($data);
}
sub serialize {
   my ($self, $entity) = @_;
my $tar = Archive::Tar->new;
   $tar->add_data('result', to_json($entity));
my $file = '/tmp/result.tgz';
   $tar->write($file, COMPRESS_GZIP);
   send_file($file, content_type => 'application/gzip', system_path => 1);
}
sub deserialize {
   my ($self, $content) = @_;
   croak "not yet implemented";
}
sub content_type {'application/gzip'}
1;