Php JSON获取Freebase API中的值

我是谷歌API的新手，正在尝试使用中的Freebase API获取特定的值。我以某种方式设计了MQL，目前我的MQL如下所示

[{
  "id": "/m/03np_7",
  "key": [{
    "namespace": "/wikipedia/en_title",
    "*": null
  }]
}]

<?php
        class Freebase{
            private $api_key = 'my-api-key';
            public function search($query, $filter = '', $start = 0, $limit = 10, $exact = 'false'){

                if(!empty($query)){
                    $query = urlencode($query);
                    $url    = 'https://www.googleapis.com/freebase/v1/search?query='. $query;
                    $url .= '&key=' . $this->api_key;
                    $url .= '&namespace=wikipedia/en_title';
                    return json_decode(file_get_contents($url), true);
                }
            }
        }

        $freebase = new Freebase();
        $result = $freebase->search('/m/03np_7');
        var_dump(json_decode("$result"));
?>

对于上面的MQL，我尝试使用PHP在程序中获取值。我的代码如下

[{
  "id": "/m/03np_7",
  "key": [{
    "namespace": "/wikipedia/en_title",
    "*": null
  }]
}]

<?php
        class Freebase{
            private $api_key = 'my-api-key';
            public function search($query, $filter = '', $start = 0, $limit = 10, $exact = 'false'){

                if(!empty($query)){
                    $query = urlencode($query);
                    $url    = 'https://www.googleapis.com/freebase/v1/search?query='. $query;
                    $url .= '&key=' . $this->api_key;
                    $url .= '&namespace=wikipedia/en_title';
                    return json_decode(file_get_contents($url), true);
                }
            }
        }

        $freebase = new Freebase();
        $result = $freebase->search('/m/03np_7');
        var_dump(json_decode("$result"));
?>

---

我希望得到的结果是“name”：“德克萨斯大学阿灵顿分校”

以下查询可能会有所帮助。你也可以在电脑上测试