script

Executes a user-defined function that returns a boolean value. The message is routed via the True connection if the function returns true, and via the False connection if it returns false. If script execution fails, the message is routed via the Failure connection. Supports TBEL and JavaScript.

Configuration

Field descriptions

• Script language — defines which scripting language is used. Can be either TBEL or JavaScript.

• Script body — the body of the function used to evaluate the incoming message. This script must return a boolean (true or false) and can access the following arguments:

  • msg — the message data, typically an object or array.
  • metadata — the message metadata. In JavaScript, this is an object where all values are strings. In TBEL, it is a java.util.Map<String, String>.
  • msgType — the type of the message as a string.

JSON Schema

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{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "TbJsFilterNodeConfiguration",
  "type": "object",
  "required": [
    "scriptLang"
  ],
  "properties": {
    "scriptLang": {
      "type": "string",
      "description": "Scripting language used to execute the function.",
      "enum": [
        "TBEL",
        "JS"
      ]
    },
    "jsScript": {
      "type": "string",
      "description": "JavaScript function body that must return a boolean value. Used when 'scriptLang' is 'JS'."
    },
    "tbelScript": {
      "type": "string",
      "description": "TBEL function body that must return a boolean value. Used when 'scriptLang' is 'TBEL'."
    }
  },
  "additionalProperties": false
}

Message processing algorithm

1. Determine which script to execute based on the configured Script language:
   • If TBEL, use the configured TBEL script.
   • If JS, use the configured JavaScript script.
2. Execute the script as a function.
3. The script must return a boolean value:
   • If true, route via the True connection.
   • If false, route via the False connection.
4. If the script throws an exception, route via the Failure connection.

Output connections

• True:
  • If the script returns true.
• False:
  • If the script returns false.
• Failure:
  • If the script returns a non-boolean value (e.g., a string or number).
  • If the script throws an error or cannot be evaluated.

Examples

The examples below show only the relevant parts of the configuration and message.

Example 1 — JavaScript script with dynamic threshold check → True

This example checks if the message type is POST_TELEMETRY_REQUEST. If so, it iterates over all numeric telemetry values in the message and compares them to threshold values from metadata. Returns true if any value exceeds its threshold.

Incoming message

Data:

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{
  "temperature": 45.2,
  "humidity": 80,
  "pressure": 1010
}

Metadata:

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{
  "temperatureThreshold": "45.0",
  "humidityThreshold": "85"
}

Message type: POST_TELEMETRY_REQUEST

Node configuration

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{
  "scriptLang": "JS",
  "jsScript": "if (msgType !== 'POST_TELEMETRY_REQUEST') {\n    return false;\n}\n\nfor (var key in msg) {\n    var thresholdKey = key + 'Threshold';\n    if (typeof msg[key] === 'number' && metadata[thresholdKey] && !isNaN(metadata[thresholdKey])) {\n        if (msg[key] > Number(metadata[thresholdKey])) {\n            return true;\n        }\n    }\n}\n\nreturn false;"
}

Result: True

Explanation: temperature (45.2) exceeds the threshold (45.0), so the script returns true.

Example 2 — TBEL script with dynamic threshold check → True

Same logic as the previous example, but implemented using TBEL.

Incoming message

Data:

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{
  "temperature": 42.1,
  "humidity": 88,
  "pressure": 1010
}

Metadata:

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{
  "temperatureThreshold": "45.0",
  "humidityThreshold": "85"
}

Message type: POST_TELEMETRY_REQUEST

Node configuration

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{
  "scriptLang": "TBEL",
  "tbelScript": "if (msgType != 'POST_TELEMETRY_REQUEST') {\n    return false;\n}\n\nforeach (key: msg.keySet()) {\n    var thresholdKey = key + 'Threshold';\n    if (metadata.containsKey(thresholdKey)) {\n        var value = msg[key];\n        var threshold = parseDouble(metadata[thresholdKey]);\n        if (value > threshold) {\n            return true;\n        }\n    }\n}\n\nreturn false;"
}

Result: True

Explanation: humidity (88) exceeds its threshold (85), so the script returns true.

Example 3 — JavaScript script, runtime error → Failure

Incoming message

Data:

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{
  "temperature": 30
}

Node configuration

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{
  "scriptLang": "JS",
  "jsScript": "// This script expects temperature inside a 'data' object.\nreturn msg.data.temperature > 20;"
}

Result: Failure

Explanation: msg.data is undefined, so accessing its property causes a runtime error.

Example 4 — TBEL script, runtime error → Failure

Incoming message

Data:

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{
  "temperature": 30
}

Node configuration

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{
  "scriptLang": "TBEL",
  "tbelScript": "// This script expects temperature inside a 'data' object.\nreturn msg.data.temperature > 20;"
}

Result: Failure

Explanation: msg.data is null, so accessing its property causes a runtime error.