Module translation_soap 

SOAP/XML protocol translation (DW-100).

The SoapTranslator implements super::translation::ProtocolTranslator for routes that bridge a REST/JSON client and a SOAP/XML upstream (or vice versa). Two directions:

• SOAP-to-REST (kind: soap_to_rest): the client sends a SOAP XML envelope; the translator parses the envelope, extracts the Body’s first child element (the operation), and converts its XML children to a JSON body the REST upstream expects.
• REST-to-SOAP (kind: rest_to_soap): the upstream returns a REST JSON body; the translator wraps it in a SOAP envelope (Envelope > Body > {operation}) with the configured operation name and namespace, converting the JSON to XML.

Minimal XML parser

A full XML library would be a new dependency (and a deny.toml review). SOAP envelopes are a narrow XML subset: elements with optional attributes, text content, and nested elements – no DTDs, no entity expansion, no processing instructions. A minimal hand-rolled parser handles that subset and rejects everything else (fail-closed against anything it cannot prove well-formed). The parser is bounded: a depth cap prevents element-nesting DoS, and a size cap rejects oversized bodies before parsing.

XML <-> JSON convention

The conversion follows a simple, deterministic convention:

• An element with only text content -> a JSON string (or number/bool when the text parses as one).
• An element with child elements -> a JSON object mapping each child tag to its converted value. Repeated child tags become a JSON array.
• Attributes -> a @attr key in the object.

This is sufficient for SOAP body payloads (which are flat-ish data records); complex XSD types are out of scope for the hand-rolled converter.

Feature gating

Compiled under the soap cargo feature (which implies protocol_translation).

Structs

SoapTranslator

The SOAP-to-REST / REST-to-SOAP translator.

XmlElement

A parsed XML element: name (qualified, prefix retained), attributes, and children (elements and text).

Enums

SoapDirection

The translation direction.

XmlChild

One child of an XML element: a nested element or a text run.