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diff --git a/perllib/Open311/Endpoint/Spark.pm b/perllib/Open311/Endpoint/Spark.pm
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+++ b/perllib/Open311/Endpoint/Spark.pm
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+package Open311::Endpoint::Spark;
+use Moo;
+use Data::Visitor::Callback;
+
+=head1 NAME
+
+Open311::Endpoint::Spark - transform from canonical data-structure to XML or JSON
+
+=head1 SUMMARY 
+
+The Open311 docs discuss the Spark convention, to transform between XML and JSON.
+
+    http://wiki.open311.org/JSON_and_XML_Conversion#The_Spark_Convention
+
+These options seem fragile, and require starting with the verbose XML form,
+which isn't really natural in Perl.  Instead, we'll start with a standard
+Perl data structure, with a single extra hash wrapper, and will:
+
+    * for JSON, remove the outside hash wrapper
+
+    * for XML, for arrays, insert an extra layer with the singular name:
+        (this is the way XML::Simple knows how to do this nesting)
+
+So:
+
+    # FROM
+    {
+        foo => {
+            bars => [ 1, 2, 3 ]
+        }
+    }
+
+    # JSON (note the 'foo' has been removed
+    {
+        bars: [
+            1,
+            2,
+            3
+        ]
+    }
+
+    # XML intermediate
+    {
+        foo => {
+            bars => {
+                bar => [ 1, 2, 3 ]
+            }
+        }
+    }
+
+    # XML result
+    <foo>
+        <bars>
+            <bar>1</bar>
+            <bar>2</bar>
+            <bar>3</bar>
+        </bars>
+    </foo>
+
+=cut
+
+sub process_for_json {
+    my ($self, $data) = @_;
+    if (ref $data eq 'HASH' and scalar keys %$data == 1) {
+        my $inner = $data->{ (keys %$data)[0] };
+        $data = $inner if ref $inner;
+    }
+    return $data;
+}
+
+sub process_for_xml {
+    my ($self, $data) = @_;
+
+    # NB: in place mutation
+    _process_for_xml($data);
+    return $data;
+}
+
+# NB: in place mutation
+sub _process_for_xml {
+    my $data = shift;
+    return unless ref $data;
+
+    if (ref $data eq 'HASH') {
+        while ( my ($k, $v) = each %$data) {
+            if (ref $v eq 'ARRAY') {
+                my $singular = _singularize($k);
+                # add extra layer
+                $data->{$k} = { 
+                    $singular => $v,
+                };
+            }
+            _process_for_xml($v);
+        }
+    }
+    elsif (ref $data eq 'ARRAY') {
+        for my $item (@$data) {
+            _process_for_xml($item);
+        }
+    }
+}
+
+my %singular_map = (
+    service_requests => 'request',
+);
+sub _singularize {
+    my $name = shift;
+    return $singular_map{ $name }
+        || do {
+            # strip final 's' if present
+            $name =~ s/s$//;
+            return $name;
+        };
+}
+
+1;