Convert Body

The Convert Body step is a Message Translator (Hohpe & Woolf). It converts the exchange body to a target BodyType variant so downstream steps read the same data under a different type.

    let route_text_to_json = RouteBuilder::from("timer:text-to-json?period=2000&repeatCount=3")
        .route_id("text-to-json")
        .set_body(r#"{"message": "hello from text", "count": 42}"#)
        .log(
            "Route 1: Starting with Text body containing JSON string",
            LogLevel::Info,
        )
        .convert_body_to(BodyType::Json)
        .log(
            "Route 1: Converted Text → Json successfully!",
            LogLevel::Info,
        )
        .to("log:info?showBody=true")
        .error_handler(ErrorHandlerConfig::log_only())
        .build()?;

- id: text-to-json
  from: timer:text-to-json?period=2000&repeatCount=3
  error_handler:
    retry:
      max_attempts: 0
  steps:
    - set_body:
        value: '{"message": "hello from text", "count": 42}'
    - convert_body_to: json
    - to: log:info?showBody=true

The .convert_body_to(BodyType::Json) call picks a target variant from the BodyType enum: Json, Bytes, or Text. The step reads the current body, re-encodes it to that variant, and stores the result on the exchange. Steps after the conversion then read the body under its new type.

Use Convert Body when the data is correct but the type is wrong. A source that emits bytes and a sink that expects JSON sit at a type boundary. The step changes the type and keeps the content. Transform does a different job. It replaces the body from an expression or a literal value. Convert Body re-types the existing data. Transform overwrites it.

Convert Body works only within the built-in BodyType variants. Marshal and Unmarshal handle named wire formats such as CSV or Protobuf. Those steps translate between a structured type and a serialized representation, not between body types.

Per ADR-0001, the step compiles into a Service<Exchange> in the Tower middleware pipeline. The processor contract and BodyType definition are documented in camel-processor/CONTEXT.md.

The example source is at examples/convert-body-to.