Transformations

MAPS Transformations allow you to modify, enrich, or convert event payloads inline as they move through the system.

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Capabilities

• Field mapping – rename, extract, or drop fields.
• Unit conversion – e.g., Fahrenheit → Celsius.
• Enrichment – add metadata such as serverId, geo tags, or custom attributes.
• Format conversion – JSON ↔ Avro ↔ Protobuf ↔ CSV (schema-driven).
• Protocol message conversion – encode/decode full events into different wire representations.

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Schema Awareness

• With a schema, MAPS applies type-aware transforms (numeric conversions, field extraction, validation).
• Without a schema, only opaque, byte-level transformations are possible.

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Transformation Flow

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Built-in Transformations

Transformation	Description
JSONToXML	Converts JSON payloads into XML documents.
XMLToJSON	Converts XML payloads into JSON.
JsonToValue	Extracts a specific value from a JSON object by key.

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Example: Schema-Aware Unit Conversion

transformations:
  - field: temperatureF
    convertTo: temperatureC
    function: fahrenheitToCelsius

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Example: Topic/Protocol-Scoped Transformations

transformations:
  data:
    - pattern: "*://*/*/*"
      transformation: ""

    - pattern: "*://*/mqtt/thermometer"
      transformation: JsonToValue
      key: temperature
      
    - pattern: "*://*/mqtt/xml_source"
      transformation: XMLtoJSON

    - pattern: "*://*/mqtt/xml_sink"
      transformation: JSONToXML

These rules apply per topic/protocol/host pattern, allowing localized transformations.

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Protocol Message Transformations

At the event ingress/egress boundary, transformations can be applied to entire protocol messages:

Transformation	Description
none	No transformation applied.
JMSProtocol	Converts events into Apache AMQP JMS-style messages.
JsonMessage	Encodes the full MAPS event as JSON (including headers, payload, metadata).
BinaryMessage	Encodes the event into a binary representation (efficient transfer).
SchemaToJson	Used for server↔server schema exchange and replication.

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Where Used

• Client connections – inbound/outbound per topic or protocol.
• Inter-server connections – bridge traffic transformed before routing.
• Pipelines – prepare payloads for downstream filtering or statistics.