如何在生成的JSON-LD中隐藏数字数组键？

我正尝试为网站添加JSON-LD，现有一个JSON数组，但因数组键的存在导致其无效。我通过以下方式追加数组数据：

$data[] = $extra_array_data;

我原本以为这样不会生成0、1、2这类数组键，但转换为JSON时却出现了。生成的JSON如下：

{
    "@context": "https://schema.org",
    "@graph": {
        "0": {
            "@type": [
                "WebPage"
            ],
            "@id": "https://example.com/#website",
            "url": "https://example.com/",
            "name": "example.com",
            "description": null,
            "inLanguage": "nl"
        },
        "@type": [
            "WebPage"
        ],
        "@id": "https://example.com/#webpage",
        "url": "https://example.com/contact",
        "name": null,
        "isPartOf": {
            "@id": "https://example.com#website"
        },
        "datePublished": "2023-03-13T21:29:43.3600Z",
        "dateModified": "2023-03-13T21:29:43.3600Z",
        "description": "",
        "inLanguage": "nl-NL",
        "potentialAction": {
            "@type": "ReadAction",
            "target": [
                "https://example.com/contact"
            ]
        }
    }
}

JSON编码代码如下：

$json_data = json_encode($return_data, JSON_UNESCAPED_UNICODE);

问题原因 #

核心问题在于@graph对应的PHP结构被搞成了关联数组，而不是JSON-LD要求的索引数组。你用$data[] = $extra_array_data追加数据时，如果$data原本已经是带@type、@id这类键的关联数组，再用[]追加就会自动给新元素加上数字索引（0、1...），转成JSON后就出现了"0": {...}这种不符合规范的结构。

JSON-LD的@graph必须是方括号包裹的JSON数组，而不是花括号包裹的键值对对象。

修复方法 #

1. 先把@graph初始化为空索引数组：

   $return_data['@graph'] = [];
   

2. 往@graph里加内容时，直接用索引数组的追加方式：

   // 加入第一个网页数据
   $return_data['@graph'][] = [
       "@type" => ["WebPage"],
       "@id" => "https://example.com/#website",
       "url" => "https://example.com/",
       "name" => "example.com",
       "description" => null,
       "inLanguage" => "nl"
   ];
   
   // 加入第二个网页数据
   $return_data['@graph'][] = [
       "@type" => ["WebPage"],
       "@id" => "https://example.com/#webpage",
       "url" => "https://example.com/contact",
       "name" => null,
       "isPartOf" => ["@id" => "https://example.com#website"],
       "datePublished" => "2023-03-13T21:29:43.3600Z",
       "dateModified" => "2023-03-13T21:29:43.3600Z",
       "description" => "",
       "inLanguage" => "nl-NL",
       "potentialAction" => [
           "@type" => "ReadAction",
           "target" => ["https://example.com/contact"]
       ]
   ];
   

3. 这样编码后的JSON就会是符合要求的结构：

   {
       "@context": "https://schema.org",
       "@graph": [
           {
               "@type": ["WebPage"],
               "@id": "https://example.com/#website",
               "url": "https://example.com/",
               "name": "example.com",
               "description": null,
               "inLanguage": "nl"
           },
           {
               "@type": ["WebPage"],
               "@id": "https://example.com/#webpage",
               "url": "https://example.com/contact",
               "name": null,
               "isPartOf": {
                   "@id": "https://example.com#website"
               },
               "datePublished": "2023-03-13T21:29:43.3600Z",
               "dateModified": "2023-03-13T21:29:43.3600Z",
               "description": "",
               "inLanguage": "nl-NL",
               "potentialAction": {
                   "@type": "ReadAction",
                   "target": ["https://example.com/contact"]
               }
           }
       ]
   }
   

注意事项 #

• 检查初始化逻辑，别一开始就把@graph设为关联数组。
• 合并数据时优先用索引数组的追加方式，别混合关联数组操作。

内容的提问来源于stack exchange，提问作者Alex