PHP服务器端将xml转换为json，结果有不同的格式

Question

我正在尝试将xml转换为json，我尝试使用以下代码，

$xml = simplexml_load_string($response, 'SimpleXMLElement', LIBXML_NOCDATA);
$json = json_encode($xml);
$arr = json_decode($json,true);

这段代码运行良好，但有一个问题， XML文件中的某些内容有可能有多个值或只有一个值，这些值的XML转换结果会有所不同，对于单值它将是与单个值关联的键，对于多值，它将返回一个数组。我的问题是如何确保返回值是一致的。

这里是返回值的例子。

多值

"item": [
                    {
                        "product_id": "XL2",
                        "description": "222 For You",
                        "d_image": "D_NUL.png",
                        "m_image": "M_NUL.png",
                        "dm_image": "DM_NUL.png",
                        "whole_toppings": {
                            "topping": "PEPPERONI"
                        },
                        "left_toppings": {
                            "topping": "MUSHROOMS"
                        },
                        "right_toppings": {
                            "topping": "ANCHOVIES"
                        },
                        "crust": "THICK CRUST (REGULAR)",
                        "sauce": "REGULAR",
                        "cook": "REGULAR"
                    },
                    {
                        "product_id": "XLA",
                        "description": [],
                        "d_image": "D_NUL.png",
                        "m_image": "M_NUL.png",
                        "dm_image": "DM_NUL.png",
                        "whole_toppings": {
                            "topping": "PEPPERONI"
                        },
                        "left_toppings": {
                            "topping": "MUSHROOMS"
                        },
                        "right_toppings": {
                            "topping": "ANCHOVIES"
                        },
                        "crust": "THICK CRUST (REGULAR)",
                        "sauce": "REGULAR",
                        "cook": "REGULAR"
                    }
                ]
            },

单值：

"item": {
                    "product_id": "MMED",
                    "description": "Mediterranean",
                    "d_image": "D_NUL.png",
                    "m_image": "M_NUL.png",
                    "dm_image": "DM_NUL.png",
                    "whole_toppings": {
                        "topping": [
                            "PEPPERONI",
                            "NO ONIONS",
                            "NO FETA CHEESE",
                            "NO SEASONED BEEF",
                            "NO TOMATOES"
                        ]
                    },

我的预期结果是

"item": [{
                    "product_id": "MMED",
                    "description": "Mediterranean",
                    "d_image": "D_NUL.png",
                    "m_image": "M_NUL.png",
                    "dm_image": "DM_NUL.png",
                    "whole_toppings": {
                        "topping": [
                            "PEPPERONI",
                            "NO ONIONS",
                            "NO FETA CHEESE",
                            "NO SEASONED BEEF",
                            "NO TOMATOES"
                        ]
                    }],

感谢您的帮助。

Answer 1

您依赖于 SimpleXML 的自动对象序列化。这里没有可用的信息表明 XML 元素可能具有同名的兄弟姐妹。该信息不存在，因此没有自动转换可以创建您想要的输出。 （并非没有提供该信息的东西。）

您将需要遍历 XML 树并生成您的特定输出。这是一个简化的示例：

$xml = <<<'XML'
<items>
  <item>
    <product_id>1</product_id>
    <whole_toppings>
      <topping>PEPPERONI</topping>
    </whole_toppings>
  </item>
  <item>
    <product_id>2</product_id>
    <whole_toppings>
      <topping>PEPPERONI</topping>
      <topping>MUSHROOMS</topping>
    </whole_toppings>
  </item>
</items>
XML;

$itemsElement = new SimpleXMLElement($xml);

$items = [];
foreach ($itemsElement->item as $itemElement) {
  $item = [
    'product_id' => (string)$itemElement->product_id,
    'whole_toppings' => [] ,
    'left_toppings' => [] 
  ];
  if ($itemElement->whole_toppings) {
    foreach ($itemElement->whole_toppings->topping as $toppingElement) {
     $item['whole_toppings'][] = (string)$toppingElement;
    }
  }
  if ($itemElement->left_toppings) {
    foreach ($itemElement->left_toppings->topping as $toppingElement) {
       $item['left_toppings'][] = (string)$toppingElement;
    }
  }
  $items[] = $item;
}

echo json_encode($items, JSON_PRETTY_PRINT);

输出：

[
  {
    "product_id":"1",
    "whole_toppings":[
      "PEPPERONI"
    ],
    "left_toppings":[

    ]
  },
  {
    "product_id":"2",
    "whole_toppings":[
      "PEPPERONI",
      "MUSHROOMS"
    ],
    "left_toppings":[

    ]
  }
]

最初需要做更多的工作，但它为您提供了对输出的更多控制。如您所见，JSON 输出包含两个产品的 whole_toppings 数组和 left_toppings 数组（但在 XML 中没有标记）。

要优化它，您可以将逻辑重构为辅助函数/方法。

function readToppingsList(
  SimpleXMLElement $itemElement, 
  string $listName, 
  string $itemName = 'topping'
): array {
  $toppings = [];
  if ($itemElement->{$listName}) {
    foreach ($itemElement->{$listName}->{$itemName} as $toppingElement) {
      $toppings[] = (string)$toppingElement;
    }
  }
  return $toppings;
}

$itemsElement = new SimpleXMLElement($xml);

$items = [];
foreach ($itemsElement->item as $itemElement) {
  $item = [
    'product_id' => (string)$itemElement->product_id,
    'whole_toppings' => readToppingsList($itemElement, 'whole_toppings'),
    'left_toppings' => readToppingsList($itemElement, 'left_toppings')
  ];
  $items[] = $item;
}

echo json_encode($items, JSON_PRETTY_PRINT);