json - 在逻辑应用程序 JSON 数组中解析单个对象的抛出错误但对于多个对象它工作正常

Question

在我的数组中解析 A​​zure Logic App 中的 JSON 时，我可以获得单个或多个值/对象(如下例所示的框)

两种类型的输入都是正确的，但是当只有一个对象出现时，它是 抛出错误“无效类型。预期数组但得到对象”

输入 1(抛出错误): -

{ 

 "MyBoxCollection": 
             {
              "Box":{
              "BoxName": "Box 1"
              }
             }
}

输入 2(工作正常): -

  { 

     "MyBoxCollection": 
                 [
                 {
                  "Box":{
                  "BoxName": "Box 1"
                  },
                  "Box":{
                  "BoxName": "Box 2"
                  }
                 }]
    }

JSON 模式:

"MyBoxCollection": {
          "type": "object",
          "properties": {
            "box": {
              "type": "array",
                items": {
                "type": "object",
                "properties": {
                  "BoxName": {
                    "type": "string"
                  },
......
.....
..
}

错误详情:-

[
  {
    "message": "Invalid type. Expected Array but got Object .",
    "lineNumber": 0,
    "linePosition": 0,
    "path": "Order.MyBoxCollection.Box",
    "schemaId": "#/properties/Root/properties/MyBoxCollection/properties/Box",
    "errorType": "type",
    "childErrors": []
  }
]

Answer 1

正如其他帖子所建议的那样，我曾经使用在结果集中注入(inject)几个虚拟行的技巧，但我最近找到了一种更好的方法。感谢 Thomas Prokov 在 his NETWORG blog post 中提供灵感.
JSON 解析模式接受多种选择作为类型，因此只需替换

"type": "array"

和

"type": ["array","object"]

并且您的解析步骤将愉快地解析数组或单个值(或根本没有值)。
然后，您可能需要确定您所处的场景:结果集中有 0、1 条或多条记录？我将在下面粘贴如何创建一个变量(ResultsetSize)，该变量为您的开关采用 3 个值(rs_0、rs_1 或 rs_n)之一:

"Initialize_ResultsetSize": {
    "inputs": {
        "variables": [
            {
                "name": "ResultsetSize",
                "type": "string",
                "value": "rs_n"
            }
        ]
    },
    "runAfter": {
        "<replace_with_name_of_previous_action>": [
            "Succeeded"
        ]
    },
    "type": "InitializeVariable"
},
"Check_if_resultset_is_0_or_1_records": {
    "actions": {
        "Set_ResultsetSize_to_0": {
            "inputs": {
                "name": "ResultsetSize",
                "value": "rs_0"
            },
            "runAfter": {},
            "type": "SetVariable"
        }
    },
    "else": {
        "actions": {
            "Set_ResultsetSize_to_1": {
                "inputs": {
                    "name": "ResultsetSize",
                    "value": "rs_1"
                },
                "runAfter": {},
                "type": "SetVariable"
            }
        }
    },
    "expression": {
        "and": [
            {
                "equals": [
                    "@string(body('<replace_with_name_of_Parse_JSON_action>')?['<replace_with_name_of_root_element>']?['<replace_with_name_of_list_container_element>']?['<replace_with_name_of_item_element>']?['<replace_with_non_null_element_or_attribute>'])",
                    ""
                ]
            }
        ]
    },
    "runAfter": {
        "Initialize_ResultsetSize": [
            "Succeeded"
        ]
    },
    "type": "If"
},
"Process_resultset_depending_on_ResultsetSize": {
    "cases": {
        "Case_no_record": {
            "actions": {
            },
            "case": "rs_0"
        },
        "Case_one_record_only": {
            "actions": {
            },
            "case": "rs_1"
        }
    },
    "default": {
        "actions": {
        }
    },
    "expression": "@variables('ResultsetSize')",
    "runAfter": {
        "Check_if_resultset_is_0_or_1_records": [
            "Succeeded",
            "Failed",
            "Skipped",
            "TimedOut"
        ]
    },
    "type": "Switch"
}