jsSwitch component: script routing. Executes the configured JS script. The script should return an array of the names of the next or multiple chains to which the message should be routed.

JavaScript script supports ECMAScript 5.1(+) syntax specification and some ES6 specifications, such as: async/await/Promise/let. It allows calling Go custom functions in the script, please refer to udf .

Configuration

Field	Type	Description	Default value
jsScript	string	js script	None

• jsScript: You can filter msg, metadata, msgType. This field is the following function body content

      function JsSwitch(msg, metadata, msgType) { 
          ${jsScript} 
       }
  

  • msg: Message content, if dataType=JSON, type is: jsonObject, you can use msg.temperature to operate. If dataType is other types, the field type is:string
  • metadata: Message metadata, type: jsonObject
  • msgType: Message type
  • Function return value type: array, an array of the names of the next or multiple chains to which the message should be routed

Note

Script execution timeout configuration reference: config.ScriptMaxExecutionTime

Relation Type

Use the script custom return value to connect to the next or multiple nodes, if there is no matching node, the Other matching node will be used.

Execution result

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

Configuration example

  {
    "id": "s1",
    "type": "jsSwitch",
    "name": "Script routing",
    "configuration": {
      "jsScript": "return ['one','two'];"
    }
  }

Application example

Using this component, you can dynamically control the logic of connecting to the next or multiple nodes. For example: Automatic marketing system, after receiving an event, trigger a query of the visitor data for the last 3 days and 30 days (these two nodes are triggered in parallel), and then process the data separately.

{
  "ruleChain": {
    "id":"rule01",
    "name": "Test rule chain",
    "root": true
  },
  "metadata": {
    "nodes": [
      {
        "id": "s1",
        "type": "jsSwitch",
        "name": "Script routing",
        "configuration": {
          "jsScript": "if msgType=='aa'{ return ['visitors_3days','visitors_30days'];}else {return ['visitors_3days','visitors_30days','visitors_60days'];}"
        }
      },
      {
        "id": "s2",
        "type": "dbClient",
        "name": "Query visitors for the last 3 days",
        "configuration": {
          "dbType":"mysql",
          "dsn":"root:root@tcp(127.0.0.1:3306)/test",
          "sql":"select * from users where DATE_SUB(CURDATE(), INTERVAL 3 DAY)<=visitor_time"
        }
      },
      {
        "id": "s3",
        "type": "dbClient",
        "name": "Query visitors for the last 30 days",
        "configuration": {
          "dbType":"mysql",
          "dsn":"root:root@tcp(127.0.0.1:3306)/test",
          "sql":"select * from users where DATE_SUB(CURDATE(), INTERVAL 30 DAY)<=visitor_time"
        }
      },
      {
        "id": "s4",
        "type": "dbClient",
        "name": "Query visitors for the last 60 days",
        "configuration": {
          "dbType":"mysql",
          "dsn":"root:root@tcp(127.0.0.1:3306)/test",
          "sql":"select * from users where DATE_SUB(CURDATE(), INTERVAL 60 DAY)<=visitor_time"
        }
      }
    ],
    "connections": [
      {
        "fromId": "s1",
        "toId": "s2",
        "type": "visitors_3days"
      },
      {
        "fromId": "s1",
        "toId": "s3",
        "type": "visitors_30days"
      },
      {
        "fromId": "s1",
        "toId": "s4",
        "type": "visitors_60days"
      }
    ]
  }
}