JSON Property keys flattener

flattenertest.php

<?PHP
CONST JSON_INPUT = '
{
  "@context": {
    "ore": "http://www.openarchives.org/ore/terms/",
    "skos": "http://www.w3.org/2004/02/skos/core#",
    "dc": "http://purl.org/dc/elements/1.1/",
    "edm": "http://www.europeana.eu/schemas/edm/",
    "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
    "dcterms": "http://purl.org/dc/terms/",
    "foaf": "http://xmlns.com/foaf/0.1/",
    "geo": "http://www.w3.org/2003/01/geo/wgs84_pos#"
  },
  "@graph": [
    {
      "@id": "http://data.europeana.eu/aggregation/europeana/09102/_CM_0839888",
      "@type": "edm:EuropeanaAggregation",
      "dc:creator": "Europeana",
      "edm:aggregatedCHO": {
        "@id": "http://data.europeana.eu/item/09102/_CM_0839888"
      },
      "edm:collectionName": "09102_Ag_EU_MIMO_ESE",
      "edm:country": "Europe",
      "edm:landingPage": {
        "@id": "http://www.europeana.eu/portal/record/09102/_CM_0839888.html"
      },
      "edm:language": "mul",
      "edm:rights": {
        "@id": "http://creativecommons.org/licenses/by-nc-sa/3.0/"
      }
    },
    {
      "@id": "http://data.europeana.eu/aggregation/provider/09102/_CM_0839888",
      "@type": "ore:Aggregation"
    },
    {
      "@id": "http://data.europeana.eu/item/09102/_CM_0839888",
      "@type": "edm:ProvidedCHO"
    },
    {
      "@id": "http://data.europeana.eu/proxy/europeana/09102/_CM_0839888",
      "@type": "ore:Proxy"
    },
    {
      "@id": "http://data.europeana.eu/proxy/provider/09102/_CM_0839888",
      "@type": "ore:Proxy"
    },
    {
      "@id": "http://mediatheque.cite-musique.fr/masc/play.asp?ID=0839888",
      "@type": "edm:WebResource"
    },
    {
      "@id": "http://semium.org/time/1910",
      "@type": "edm:TimeSpan"
    },
    {
      "@id": "http://semium.org/time/19xx_1_third",
      "@type": "edm:TimeSpan"
    },
    {
      "@id": "http://sws.geonames.org/2950159",
      "@type": "edm:Place"
    },
    {
      "@id": "http://www.geonames.org/2950159",
      "@type": "edm:Place"
    },
    {
      "@id": "http://www.mimo-db.eu/InstrumentsKeywords/4495",
      "@type": "skos:Concept"
    },
    {
      "@id": "http://www.mimo-db.eu/media/MF-GET/IMAGE/MFIM000024482.jpg",
      "@type": "edm:WebResource"
    }
  ]
}
';

CONST JSON_PERSON = '
{
      "@context": "http://schema.org",
      "@type": "Person",
      "address": {
        "@type": "PostalAddress",
        "addressLocality": "Colorado Springs",
        "addressRegion": "CO",
        "postalCode": "80840",
        "streetAddress": "100 Main Street"
      },
      "colleague": [
        "http://www.example.com/JohnColleague.html",
        "http://www.example.com/JameColleague.html"
      ],
      "email": "mailto:info@example.com",
      "image": "janedoe.jpg",
      "jobTitle": "Research Assistant",
      "name": "Jane Doe",
      "alumniOf": "Dartmouth",
      "birthPlace": "Philadelphia, PA",
      "birthDate": "1979.10.12",
      "height": "72 inches",
      "gender": "female",
      "memberOf": "Republican Party",
      "nationality": "African American",
      "telephone": "(123) 456-6789",
      "url": "http://www.example.com",
	    "sameAs" : [ "https://www.facebook.com/",
      "https://www.linkedin.com/",
      "http://twitter.com/",
      "http://instagram.com/",
      "https://plus.google.com/"]
    }
    ';
    
CONST MANY_NODES ='
{
  "@context": {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@graph": [
    {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/bob/",
      "foaf:name": "Bob"
    }, {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/eve/",
      "foaf:name": "Eve"
    }, {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/manu/",
      "foaf:name": "Manu"
    }
  ]
}';   

CONST NAMED_GRAPH = '{
  "@context": {
    "generatedAt": {
      "@id": "http://www.w3.org/ns/prov#generatedAtTime",
      "@type": "http://www.w3.org/2001/XMLSchema#date"
    },
    "Person": "http://xmlns.com/foaf/0.1/Person",
    "name": "http://xmlns.com/foaf/0.1/name",
    "knows": {"@id": "http://xmlns.com/foaf/0.1/knows", "@type": "@id"}
  },
  "@id": "http://example.org/foaf-graph",
  "generatedAt": "2012-04-09",
  "@graph": [
    {
      "@id": "http://manu.sporny.org/about#manu",
      "@type": "Person",
      "name": "Manu Sporny",
      "knows": "http://greggkellogg.net/foaf#me"
    }, {
      "@id": "http://greggkellogg.net/foaf#me",
      "@type": "Person",
      "name": "Gregg Kellogg",
      "knows": "http://manu.sporny.org/about#manu"
    }
  ]
}';

function jsonIsList(array $sourcearray =  []) {
      return empty(array_filter(array_keys($sourcearray), 'is_string'));
  }

    
function array_flatten($array, $prefix = '') {

    $result = array();
    foreach ($array as $key=>$value) {
        if (is_array($value)) {
            $result = $result + array_flatten($value, $prefix.$key.'.');
        }
        else {
            $result[$prefix.$key] = $value;
        }
    }

    return $result;
}

function array_flatten2($array, &$flat = array(), $jsonld = TRUE) {

    if (($jsonld) && array_key_exists('@graph', $array)) {
        $array = $array['@graph'];
    }
    foreach ($array as $key=>$value) {
        if (is_array($value)) {
            if (jsonIsList($value)) {
                print_r('numeric index');
            }
            array_flatten2($value, $flat);
            
            
        }
        else {
            $flat[$key][] = $value;
        }
    }
    return $flat;
}


print_r(json_decode(NAMED_GRAPH, TRUE));

print_r(array_flatten(json_decode(NAMED_GRAPH, TRUE)));

$flat = array();
print_r(array_flatten2(json_decode(NAMED_GRAPH, TRUE),$flat));
print_r($flat);