Transform

These three processors are always part of the server, except that the SCRIPT mode of MAPPER needs the optional script-js module (see Built-in plugins). Options marked “expression” take the expression language described in Variables and expressions. Inside an expression the message is the root, so payload.price reads a payload field. These plugins do not resolve ${...} variables in their options. Unless a section says otherwise, the default timeout is the engine default of 30 seconds idle.

MAPPER

Rebuilds the payload of each message. It has three modes.

Option	Type	Default	Meaning
`mode`	`PROJECTION`, `TEMPLATE` or `SCRIPT`	none, required	How the mapping is applied
`mapping`	map or string	none, required	See the table below
`dropOriginal`	boolean	`true`	`true` keeps only what the mapping builds. `false` keeps the original payload and adds or overwrites the mapped fields
`strictMode`	boolean	`true`	Fail the message when evaluation fails. When `false`, the failure is logged and processing goes on

Output port: default. The message keeps its id and metadata; only the payload changes.

Mode	`mapping` is	Result
`PROJECTION`	A map of target field to expression. A dot in the target nests the value: `user.id` builds `{"user": {"id": ...}}`	An object with the mapped fields
`TEMPLATE`	A map of target field to a template, or one template string	With a map, an object whose values are the rendered text. With a string, the payload becomes the rendered text
`SCRIPT`	A JavaScript string	The value of the script’s last expression

A template uses double-brace placeholders such as hi {{payload.name}}. A payload that is not an object is wrapped as {"value": <payload>} when dropOriginal is false in PROJECTION mode. With strictMode off, a projection field whose expression gives null is left out, and a failing script gives an empty payload (or the original payload when dropOriginal is false). With strictMode on, a null result is written as null and any evaluation error fails the message.

SCRIPT mode

A script sees three values: message, payload and metadata. Its result is the value of its last expression, converted to plain objects, lists and scalars. An object literal needs parentheses:

({ total: payload.items.length, label: 'order-' + payload.id })

Scripts are limited:

Limit	Value
Run time	10 seconds, then the script is cancelled
Statements	50 million, then the script is stopped
Types a script can load	A short list of value types, such as `Math`, `String`, `UUID`, `Base64`, lists, maps and the date-time types. Anything else is refused
Memory	not limited

The run-time and statement limits are server start-up settings, yukta.script.timeout-ms (10000) and yukta.script.max-statements (50000000). A SCRIPT node is rejected at validation when the script-js module is not in the build. Prefer PROJECTION for simple reshaping: it is faster and cannot reach anything outside the message.

{
  "nodeId": "shape",
  "type": "MAPPER",
  "config": {
    "mode": "PROJECTION",
    "mapping": { "userId": "payload.id", "label": "'user:' + payload.name" }
  }
}

With the payload {"id": 1, "name": "Ada", "active": true} this node emits {"userId": 1, "label": "user:Ada"}. This node writes a text payload from a template:

{
  "nodeId": "message-text",
  "type": "MAPPER",
  "config": { "mode": "TEMPLATE", "mapping": "Build {{payload.build}} finished: {{payload.status}}" }
}

VALIDATE

Checks required fields and field types on the payload and routes bad messages to the invalid port, so bad input can be set aside instead of failing a later node.

Option	Type	Default	Meaning
`required`	list	none	Field names that must be present and not null
`types`	map	none	Field name to one of `string`, `number`, `boolean`, `object` or `array`

At least one of required and types must be set. A field listed in types that is absent or null passes the type check; list it in required as well to insist on it. Output ports: default for valid messages and invalid for the rest. An invalid message carries every reason found, such as missing field: email; field qty is not number, as its failure reason. A payload that is not an object is invalid with the reason payload is not an object.

{
  "nodeId": "check-order",
  "type": "VALIDATE",
  "config": {
    "required": ["orderId", "email"],
    "types": { "orderId": "string", "qty": "number", "items": "array" }
  }
}

[
  { "source": "check-order", "target": "process-order" },
  { "source": "check-order", "target": "quarantine", "sourcePort": "invalid" }
]

CONTENT-FILTER

Keeps or removes parts of a message. Use it to strip sensitive or unimportant fields before logging or sending a payload on. The type string is written with a hyphen.

Option	Type	Default	Meaning
`mode`	`INCLUDE` or `EXCLUDE`	`INCLUDE`	`INCLUDE` keeps only the listed paths. `EXCLUDE` removes the listed paths
`paths`	list	none, required	The paths. See below
`flatten`	boolean	`false`	Turn nested objects in the result payload into one level with dotted keys, so `{"a": {"b": 1}}` becomes `{"a.b": 1}`
`strictMode`	boolean	`true`	`INCLUDE` mode: fail when a listed payload path is missing. When `false`, a failure passes the message on unchanged
`errorPort`	string	none	Port for messages that fail, with the failure details attached

Output ports: default, plus errorPort when set. Paths:

A plain path such as user.name refers to the payload.
A path starting with metadata. or headers. refers to the message metadata.
In INCLUDE mode a path may also be an expression. A path that starts with # is evaluated as one.
In EXCLUDE mode paths are plain dotted names. Missing paths are ignored.

With INCLUDE, the new payload holds only the listed paths, nested as written. When any listed path targets metadata, the metadata is replaced by the listed entries plus the message’s core identifiers (message id, trace id, correlation id, timestamp, sequence fields and reply address). If the payload is a list, each item is filtered on its own and emitted as a separate message. This node removes secrets before a payload goes on:

{
  "nodeId": "redact",
  "type": "CONTENT-FILTER",
  "config": {
    "mode": "EXCLUDE",
    "paths": ["user.password", "user.token", "metadata.apiKey"]
  }
}

Limits and defaults

Item	Value
`MAPPER` `dropOriginal`, `strictMode`	`true`, `true`
Script run time and statements	10 seconds, 50 million
Script memory	not limited
`CONTENT-FILTER` `mode`	`INCLUDE`
Default timeout, all three plugins	30 seconds idle

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Reference

MAPPER

SCRIPT mode

VALIDATE

CONTENT-FILTER

Limits and defaults

​MAPPER

​SCRIPT mode

​VALIDATE

​CONTENT-FILTER

​Limits and defaults

​Related

MAPPER

SCRIPT mode

VALIDATE

CONTENT-FILTER

Limits and defaults

Related