The switch component: A conditional branching component. It matches the case expressions in sequence. If a match is found, it stops and forwards the message to the corresponding route chain. If no match is found, it forwards to the default Default chain.

Configuration

Field	Type	Description	Default Value
cases	List of Case	List of conditions	None

Case:

Field	Type	Description	Default Value
case	string	Conditional expression	None
then	string	Routing relationship	None

The case expression can use the following variables:

• Access the message ID through the id variable.
• Access the message timestamp through the ts variable.
• Access the original content of the message through the data variable.
• Access the message body through the msg variable. If the message's dataType is JSON, you can access msg fields with the msg.XX method. For example: msg.temperature > 50;
• Access message metadata through the metadata variable. For example: metadata.customerName
• Access the message type through the type variable.
• Access the data type through the dataType variable.

Expression examples:

• msg.temperature > 50
• msg.temperature > 50 && metadata.customerName == 'rulego'
• upper(metadata.customerName[:4]) == 'GO'
• replace(toJSON(msg),'name','productName')

For more information on expr expression syntax, refer to: expr (opens new window)

Relation Type

• If a case is matched, the message is sent to the chain corresponding to the then value.
• Failure: If execution fails, the message is sent to the Failure chain.

Execution Result

This component does not change the content of msg, metadata, and msgType.

Configuration Example

{
  "ruleChain": {
    "id": "bW1lMC97oYih",
    "name": "测试条件分支",
    "debugMode": true,
    "root": true
  },
  "metadata": {
    "endpoints": [],
    "nodes": [
      {
        "id": "node_2",
        "additionalInfo": {
          "description": "",
          "layoutX": 480,
          "layoutY": 280
        },
        "type": "switch",
        "name": "条件分支",
        "debugMode": false,
        "configuration": {
          "cases": [
            {
              "case": "msg.temperature>=20 && msg.temperature<=50",
              "then": "Case1"
            },
            {
              "case": "msg.temperature>50",
              "then": "Case2"
            }
          ]
        }
      },
      {
        "id": "node_4",
        "additionalInfo": {
          "description": "",
          "layoutX": 840,
          "layoutY": 160
        },
        "type": "jsTransform",
        "name": "case1",
        "debugMode": false,
        "configuration": {
          "jsScript": "msg=msg||{}\nmsg.match='Case1'\nreturn {'msg':msg,'metadata':metadata,'msgType':msgType};"
        }
      },
      {
        "id": "node_5",
        "additionalInfo": {
          "description": "",
          "layoutX": 840,
          "layoutY": 280
        },
        "type": "jsTransform",
        "name": "case2",
        "debugMode": false,
        "configuration": {
          "jsScript": "msg=msg||{}\nmsg.match='Case2'\nreturn {'msg':msg,'metadata':metadata,'msgType':msgType};"
        }
      },
      {
        "id": "node_6",
        "additionalInfo": {
          "description": "",
          "layoutX": 840,
          "layoutY": 380
        },
        "type": "jsTransform",
        "name": "default",
        "debugMode": false,
        "configuration": {
          "jsScript": "msg=msg||{}\nmsg.match='Default'\nreturn {'msg':msg,'metadata':metadata,'msgType':msgType};"
        }
      }
    ],
    "connections": [
      {
        "fromId": "node_2",
        "toId": "node_4",
        "type": "Case1"
      },
      {
        "fromId": "node_2",
        "toId": "node_5",
        "type": "Case2"
      },
      {
        "fromId": "node_2",
        "toId": "node_6",
        "type": "Default"
      }
    ]
  }
}