JOLT 如果键不存在则增加值

Question

我对这个 Jolt input 有一些问题，我会尽量直言不讳。

{
  "Root": [
    {
      "key1": "value1",
      "key2": "value2"
    },
    {
      "key1": "value1"
    }
  ]
}

如你所见，我有一个数组，里面有 2 个对象。这是我的 Jolt spec :

    [{
      "operation": "shift",
      "spec": {
        "Root": {
          "*": {
            "key1": "newkey1",
            "key2": "newkey2"
          }
        }
      }
    }]

和输出显然是这样的：

{
  "newkey1": ["value1", "value1"],
  "newkey2": "value2"
}

现在，我的问题是：当键在输入 JSON 中不存在时，是否可以在

"newkey2"

数组中添加一个空值？

我需要这样的东西：

{
  "newkey1": ["value1", "value1"],
  "newkey2": ["", "value2"]
}

这也许很容易做到，但我只是掌握了 Jolt 的窍门。

Answer 1

在你轮班之前“修复”数据，让它工作。

[
  {
    "operation": "modify-default-beta",
    "spec": {
      "Root": {
        "*": {
          // Assuming you know the keys
          //  you expect to be in the data,
          //  add default values if they don't
          //  exist.
          "key1": "",
          "key2": ""
        }
      }
    }
  },
  {
    "operation": "shift",
    "spec": {
      "Root": {
        "*": {
          // Now "shift" to the new format
          // "knowing" that all the keys will
          //  have at least default values.
          // Also, make "newkey1" always be 
          //  an array.
          "key1": "newkey1[]",
          "key2": "newkey2[]"
        }
      }
    }
  }
]

Answer 2

您可以在 modify

 转换规范中使用 

~ 运算符，根据它的存在使其成为默认值，例如

[
  {
    "operation": "modify-default-beta",
    "spec": {
      "Root": {
        "*": {
          "~key2": "" // if "key2" does not exist or is null, then default it to be ""
        }
      }
    }
  },
  {
    "operation": "shift",
    "spec": {
      "Root": {
        "*": {
          "*": "new&" // accumulate values under common keys while prefixing their names with "new" 
        }
      }
    }
  }
]