custom serializer

lib/Plack/Middleware/RDF/Flow/Serializer.pm

@@ -0,0 +1,100 @@
+use strict;
+use warnings;
+package Plack::Middleware::RDF::Flow::Serializer;
+#ABSTRACT: Lightweight RDF serializer base class
+
+use Plack::Util::Accessor qw(mime);
+use Carp;
+
+our $mime_type;
+
+# copied from Plack::Component
+sub new {
+    my $proto = shift;
+    my $class = ref $proto || $proto;
+
+    my $self;
+    if (@_ == 1 && ref $_[0] eq 'HASH') {
+        $self = bless {%{$_[0]}}, $class;
+    } else {
+        $self = bless {@_}, $class;
+    }
+
+    { 
+        no strict 'refs';
+        $self->mime( ${ ref($self) . '::mime_type' } ) unless $self->mime;
+    }
+    croak 'serializer requires a mime type' unless $self->mime;
+
+    $self;
+}
+
+sub media_types {
+    my $self = shift;
+    return ($self->mime);
+}
+
+sub serialize_model_to_string {
+    my ($self, $model) = @_;
+
+    carp 'you must implement ' . ref($self) . '::serialize_model_to_string';
+
+    return '';
+}
+
+sub serialize_iterator_to_string {
+    my ($self, $iter) = @_;
+    my $model = RDF::Trine::Model->temporary_model;
+    $model->begin_bulk_ops;
+    while (my $st = $iter->next) {
+        $model->add_statement( $st );
+    }
+    $model->end_bulk_ops;
+    return $self->serialize_model_to_string( $model );
+}
+
+1;
+
+=head1 SYNOPIS
+
+  package Your::Serializer;
+  use parent 'Plack::Middleware::RDF::Flow::Serializer';
+
+  use Plack::Util::Accessor qw(foo bar);  # config options of your serializer
+  our $mime_type = "foo/bar";             # mime type of your serializer 
+
+  sub serialize_model_to_string {
+      my ($self, $model) = @_;
+
+      # create serialization
+      
+      return $strimg;
+  }
+
+=head1 DESCRIPTION
+
+This class can be used to define custom RDF serialization formats. You can also
+use use L<RDF::Trine::Serializer>, but if you want to decouple serializer
+definition from content negotiation and if your serialization format has just
+one MIME type, this module may be an alternative.
+
+=method new ( { key => $value } )
+
+Creates a new serializer.
+
+=method media_types
+
+Returns the mime type as one-element list.
+
+=method serialize_model_to_string ( $model )
+
+Serializes a L<RDF::Trine::Model>. You must implement this method in your
+subclass.
+
+=method serialize_iterator_to_string ( $iterator )
+
+Serialize a L<RDF::Trine::Iterator::Graph>. You may implement this method
+in your class. By default it used C<serialize_model_to_string>.
+
+=cut
+