wso2-synapse-validator

XML/XSD validation engine for the WSO2 MI Language Server — Apache Xerces-C compiled to WebAssembly.

Schema is compiled once per project into a persistent WASM grammar pool. Every validate() call reuses it — no re-parsing on keystrokes.

---

How it works

---

WASM Validation: Dynamic Connector Flow

1. Server Init (Startup)

• No connectors: Load only the static core schemas (from the extension folder) and send to WASM.
• Connectors exist: Load the static schemas, generate the connectors.xsd live in RAM, merge them, and send the full text map to WASM.

2. Live Updates (Add / Remove Connector)

• The Trigger: A user downloads a new connector or deletes one.
• The Action: Instantly re-generate the connectors.xsd live in RAM to match the new state.
• The WASM Update: Send the full text map (static + updated dynamic string) to WASM again. The C++ engine needs the whole map to successfully re-compile the locked rules.

---

Multiple projects

Each project gets its own grammar pool in WASM memory. They share one WASM instance but never share state.

WASM instance (one, shared)
│
├── ProjectValidator [workspace A]  — MI 4.3.0, no connectors
│     pool: [4.3.0 grammar]
│
├── ProjectValidator [workspace B]  — MI 4.3.0, s3 connector
│     pool: [4.3.0 + s3 grammar]
│
├── ProjectValidator [workspace C]  — MI 4.4.0, no connectors
│     pool: [4.4.0 grammar]
│
└── ProjectValidator [workspace D]  — MI 4.4.0, s3 + http connectors
      pool: [4.4.0 + s3 + http grammar]

---

Setup

Requires Git, Node.js, and an internet connection for the first build. Everything else (Emscripten, Xerces-C) is fetched automatically.

git clone --recurse-submodules https://github.com/harshanacz/wso2-synapse-validator
npm install
npm run build:wasm   # installs Emscripten automatically on first run
npm test

Note: npm run build:wasm downloads the Emscripten toolchain (~500 MB) into tools/emsdk/ on the first run. Subsequent builds skip this step.

---

Build

npm run build:wasm   # compile Xerces-C → wasm/xerces_validator.{js,wasm}
npm run build:ts     # compile TypeScript → dist/
npm test

---

License

MIT — see LICENSE.
Includes Apache Xerces-C — see native/xerces-c/LICENSE.