Ibm cloud 如何使用节点red node cf cloudant从插入/更新中获得结果 我在IBM BLUMIX IOT基金会提供的No.Red工作。它附带node red node cf cloudant包，可以轻松处理cloudant数据库操作。Cloudant out节点工作得很好。border me是什么Cloudant out节点没有输出可以告诉流插入/更新操作是否成功。现在我只能假设它总是成功的。有人有和我一样的问题吗？你的解决方案是什么？谢谢。

我认为其原理是可以将

Catch

节点的概念添加到流中。请参阅标记为

catch

的节点的

input

类别。在阅读此节点的文档时，它指出，如果同一选项卡/页面/工作流上的任何节点引发错误，将触发此节点。我假设如果Cloudant out节点实现正确，那么如果它失败，它将抛出一些节点红色格式的错误，这将导致触发

Catch

节点，这样您就可以控制执行任何可能适用的错误处理、日志记录或其他补救工作

我猜想，可以在这里找到跟踪创建的节点红色Github问题，其中可以阅读更多关于该功能的信息：

---

我认为其原理是有一个可以添加到流中的

Catch

节点的概念。请参阅标记为

catch

的节点的

input

类别。在阅读此节点的文档时，它指出，如果同一选项卡/页面/工作流上的任何节点引发错误，将触发此节点。我假设如果Cloudant out节点实现正确，那么如果它失败，它将抛出一些节点红色格式的错误，这将导致触发

Catch

节点，这样您就可以控制执行任何可能适用的错误处理、日志记录或其他补救工作

我猜想，可以在这里找到跟踪创建的节点红色Github问题，其中可以阅读更多关于该功能的信息：

---

我有一个答案，尽管它不是一个很有用的答案

    [
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    "type": "cloudant out",
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    "service": "your_service",
    "cloudant": "",
    "name": "Save Data",
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    "payonly": true,
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    "field": "payload",
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    "format": "json",
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    "property": "error",
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    "type": "inject",
    "z": "7ac871fa.85379",
    "name": "",
    "topic": "",
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    "id": "9fc752f6.6038b",
    "type": "debug",
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    "name": "",
    "active": true,
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    "complete": "false",
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    "type": "debug",
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    "active": true,
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    "complete": "error",
    "x": 330,
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]

检查此代码。我可以使用catch节点捕获cloudantout节点抛出的任何错误，并将其设置为流上下文对象。因此，原始路径可以在短暂延迟后检查上下文中是否存在错误对象。如果在上下文中未找到错误，则假定更新成功

---

然而，这不是一个有用的解决方案。当在同一个节点实例中收到多个请求时，将出现并发问题。错误对象中没有会话标识符。我无法将错误消息与导致错误的消息相关联。希望有人能想出一种改进此解决方案的方法。

我有一个答案，尽管它不是一个非常有用的答案

    [
  {
    "id": "a477543c.5b88a8",
    "type": "debug",
    "z": "7ac871fa.85379",
    "name": "",
    "active": true,
    "console": "false",
    "complete": "false",
    "x": 293,
    "y": 147,
    "wires": []
  },
  {
    "id": "8c8b0763.7374f8",
    "type": "cloudant out",
    "z": "7ac871fa.85379",
    "service": "your_service",
    "cloudant": "",
    "name": "Save Data",
    "database": "your_db",
    "payonly": true,
    "operation": "insert",
    "x": 292,
    "y": 58,
    "wires": []
  },
  {
    "id": "66f48698.990b78",
    "type": "template",
    "z": "7ac871fa.85379",
    "name": "",
    "field": "payload",
    "fieldType": "msg",
    "format": "json",
    "template": "{\"response\": \"success\"}",
    "x": 669,
    "y": 112,
    "wires": [
      [
        "9fc752f6.6038b"
      ]
    ]
  },
  {
    "id": "9a2f1021.65d0f",
    "type": "catch",
    "z": "7ac871fa.85379",
    "name": "Catch error from Save Data",
    "scope": [
      "8c8b0763.7374f8"
    ],
    "x": 130,
    "y": 207,
    "wires": [
      [
        "41c37106.be3c9",
        "35676738.ca9898",
        "9e4a94f4.61b568"
      ]
    ]
  },
  {
    "id": "41c37106.be3c9",
    "type": "debug",
    "z": "7ac871fa.85379",
    "name": "",
    "active": true,
    "console": "true",
    "complete": "true",
    "x": 316,
    "y": 249,
    "wires": []
  },
  {
    "id": "35676738.ca9898",
    "type": "change",
    "z": "7ac871fa.85379",
    "name": "",
    "rules": [
      {
        "t": "set",
        "p": "error",
        "pt": "flow",
        "to": "error",
        "tot": "msg"
      }
    ],
    "action": "",
    "property": "",
    "from": "",
    "to": "",
    "reg": false,
    "x": 330,
    "y": 207,
    "wires": [
      [
        "6c19d8c0.93e628"
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    ]
  },
  {
    "id": "972775b7.68d888",
    "type": "delay",
    "z": "7ac871fa.85379",
    "name": "",
    "pauseType": "delay",
    "timeout": "3",
    "timeoutUnits": "seconds",
    "rate": "1",
    "rateUnits": "second",
    "randomFirst": "1",
    "randomLast": "5",
    "randomUnits": "seconds",
    "drop": false,
    "x": 286,
    "y": 106,
    "wires": [
      [
        "dd0eb63d.22f148"
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    ]
  },
  {
    "id": "dd0eb63d.22f148",
    "type": "switch",
    "z": "7ac871fa.85379",
    "name": "Check flow.error",
    "property": "error",
    "propertyType": "flow",
    "rules": [
      {
        "t": "nnull"
      },
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        "t": "else"
      }
    ],
    "checkall": "true",
    "outputs": 2,
    "x": 467,
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    "id": "a26776ff.5d9888",
    "type": "template",
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    "field": "payload",
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    "format": "json",
    "template": "{\"response\": {{{payload}}}}\n",
    "x": 975,
    "y": 55,
    "wires": [
      [
        "9fc752f6.6038b"
      ]
    ]
  },
  {
    "id": "54a9c22f.ab563c",
    "type": "change",
    "z": "7ac871fa.85379",
    "name": "",
    "rules": [
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        "p": "payload",
        "pt": "msg",
        "to": "error",
        "tot": "flow"
      },
      {
        "t": "delete",
        "p": "error",
        "pt": "flow"
      }
    ],
    "action": "",
    "property": "",
    "from": "",
    "to": "",
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    "name": "",
    "active": true,
    "console": "false",
    "complete": "false",
    "x": 505,
    "y": 207,
    "wires": []
  },
  {
    "id": "433fc13d.bcc04",
    "type": "inject",
    "z": "7ac871fa.85379",
    "name": "",
    "topic": "",
    "payload": "{\"_id\":\"0fc076a605741fdffa1580897e1c54a0\",\"message\":\"testing\"}",
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    "wires": []
  },
  {
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    "type": "debug",
    "z": "7ac871fa.85379",
    "name": "",
    "active": true,
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    "complete": "error",
    "x": 330,
    "y": 297,
    "wires": []
  },
  {
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    "type": "json",
    "z": "7ac871fa.85379",
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    "x": 843,
    "y": 55,
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]

检查此代码。我可以使用catch节点捕获cloudantout节点抛出的任何错误，并将其设置为流上下文对象。因此，原始路径可以在短暂延迟后检查上下文中是否存在错误对象。如果在上下文中未找到错误，则假定更新成功

---

然而，这不是一个有用的解决方案。当在同一个节点实例中收到多个请求时，将出现并发问题。错误对象中没有会话标识符。我无法将错误消息与导致错误的消息相关联。希望有人能找到一种改进此解决方案的方法。

cloudant节点的日期早于Catch节点，因此可能不会以这种方式记录错误以触发Catch节点。我知道Catch节点可能会完成这项工作，但有相当多的限制，因为很多信息没有传递给Catch节点。如果需要向用户返回正确的错误消息，很可能需要访问传递到Cloudant节点的整个消息。我开始认为我可以将捕获节点的错误保存在上下文对象（如flow或global）中。然后，原始路径将通过检查上下文中是否存在错误来知道更新是否成功。你认为这会奏效吗？@AlexHui-你提出了一个有趣的想法。就我个人而言，我认为你的要求行不通。原因是（这是一个猜测），导致Catch中唤醒的错误很可能意味着原始流的终止和Catch节点的“转到”。因此，尽管我们可以在Catch节点中设置一些全局上下文，但可能没有“其他路径”来感知它。我开始认为节点红色可能不是你需要的。。。可能需要考虑一个手写的JavaScript应用程序。Kolban，你可能是对的。我将建立一个流程来验证我的想法。我认为它可能会起作用的原因是，您总是可以从任何节点的输出分支出流。因此，即使Cloudant out确实停止了该路径上的执行流，另一个分支也可能一直运行到最后。让我们看看我会发现什么。cloudant节点在Catch节点之前，所以可能不会以触发Catch节点的方式记录错误。我知道Catch节点可能会做这项工作，但有很多限制，因为很多信息没有传递给Catch节点。如果需要向用户返回正确的错误消息，很可能需要访问传递到Cloudant节点的整个消息。我开始认为我可以将捕获节点的错误保存在上下文对象（如flow或global）中。然后，原始路径将通过检查上下文中是否存在错误来知道更新是否成功。你认为这会奏效吗？@AlexHui-你提出了一个有趣的想法。就我个人而言，我认为你的要求行不通。原因是（这是一个猜测）一个错误导致捕获中的唤醒很可能意味着错误