MT#12273 '_forcearray' attr for Data::HAL's asjson

The Data::HAL respresentation of a GET collection page provides a 'link' and 'embedded' field of the page's items. In the case the page contains a single item only, the current Data::HAL implementation does not create arrays. This is less consistent and complicates test cases at least.

Change-Id: I3ad0f2f0bf8945c2c4b6743bd2b904a14353118f

lib/Data/HAL.pm

@@ -10,7 +10,8 @@ use failures qw(Data::HAL::InvalidJSON);
 use HTTP::Headers::Util qw(join_header_words);
 use JSON qw();
 use Moo; # has
-use Safe::Isa qw($_isa);
+#use Safe::Isa qw($_isa);
+use Safe::Isa qw($_can $_isa);
 use Scalar::Util qw(reftype);
 use Types::Standard qw(ArrayRef Bool HashRef InstanceOf Str);
 
@@ -31,12 +32,34 @@ has('relation', is => 'rw', isa => InstanceOf['Data::HAL::URI'], coerce => $uri_
 has('_nsmap',   is => 'rw', isa => InstanceOf['Data::HAL::URI::NamespaceMap']);
 has('_recursing', is => 'ro', isa => Bool);
 
+has('_forcearray', is => 'rw', isa => Bool, default => 0); #array of embedded items, even if only one
+
 sub BUILD {
     my ($self) = @_;
     $self->_expand_curies unless $self->_recursing;
     return;
 }
 
+#for links array containig undef elements
+#around 'BUILDARGS' => sub {
+#    my $orig  = shift;
+#    my $class = shift;
+#    my $params;
+#    if ((scalar @_) == 1) {
+#	($params) = @_;
+#    } else {
+#	$params = { @_ };
+#    }
+#    if (reftype $params eq reftype {} && exists $params->{links}) {
+#	my @links = ();
+#	foreach my $l (@{ $params->{links} }) {
+#	    push(@links,$l) if defined $l;
+#	}
+#	$params->{links} = \@links;
+#    }
+#    $class->$orig($params);
+#};
+
 sub from_json {
     my ($self, $json, $relation) = @_;
     my $nested = clone JSON::from_json($json);
@@ -152,7 +175,11 @@ sub _to_nested {
                         push @{ $hal->{"_$prop"}{$r} }, $attr, $nested;
                     }
                 } else {
-                    $hal->{"_$prop"}{$r} = $nested;
+		    if ($p->$_can('_forcearray') and $p->_forcearray) {
+			$hal->{"_$prop"}{$r} = [ $nested ];
+		    } else {
+			$hal->{"_$prop"}{$r} = $nested;
+		    }
                 }
             }
         }

lib/Data/HAL/Link.pm

@@ -8,7 +8,7 @@ use Log::Any qw($log);
 use MIME::Type qw();
 use Moo; # has
 use Safe::Isa qw($_can $_isa);
-use Types::Standard qw(InstanceOf Str);
+use Types::Standard qw(InstanceOf Str Bool);
 
 our $VERSION = '1.000';
 
@@ -32,6 +32,8 @@ has('profile',     is => 'rw', isa => InstanceOf['Data::HAL::URI'], coerce => $u
 has('title',       is => 'rw', isa => Str);
 has('hreflang',    is => 'rw', isa => Str);
 
+has('_forcearray',    is => 'rw', isa => Bool, default => 0); #array of link items, even if only one
+
 sub BUILD {
     my ($self) = @_;
     if ($self->deprecation) {
@@ -51,6 +53,7 @@ sub _to_nested {
         }
     }
     my $r = delete $hal->{relation};
+    delete $hal->{_forcearray};
     return($hal, $r);
 }