@wapython/wasi

Javascript library for interacting with WASI Modules in Node.js.

(TODO: and in the Browser.)

This is a fork of version 0.12.0 of @wasmer/wasi to keep it alive, since the Wasmer company decided to end it, and I would like to use it in python-wasm.

Table of Contents

• Features
• Installation
• Quick Start

Features

@wapython/wasi uses the same API as the future WASI integration in Node.

However, @wapython/wasi is focused on:

• Bringing WASI to an Isomorphic context (Node.js and the Browser)
• Make it easy to plug in different filesystems (via wasmfs)
• Make it type-safe using Typescript
• Pure JavaScript implementation (no Native bindings needed)
• Very small

Installation

To install @wapython/wasi, run this command:

npm install @wapython/wasi

Quick Start

This quick start is for node. It's something like this. See lib/src/wasm.ts in the JSage source code for something that uses @wapython/wasi in a real application for a better tested example.

import { WASI } from "@wapython/wasi";
import fs from "fs";
import nodeBindings from "@wapython/wasi/dist/bindings/node";

const wasi = new WASI({
  args: [],
  env: {},
  bindings: {...nodeBindings, fs},
});

const source = await readFile(pathToWasm);
const typedArray = new Uint8Array(source);
const result = await WebAssembly.instantiate(typedArray, wasmOpts);
wasi.start(result.instance);

Use DEBUG=wasi to see a log of all wasi system calls; this uses the debug library.

History and Copyright

This project is based on what the wasmer devs wrote, which itself was based on what Gus Caplan wrote. I have been using this library extensively in python-wasm, and have found and fixed tricky low level bugs in the implementation. I have also added hooks for using Atomics and SharedArrayBuffers to implement blocking IO.

Here's what the WASMER people wrote:

This project is based from the Node implementation made by Gus Caplan
https://github.com/devsnek/node-wasi
However, JavaScript WASI is focused on:
 * Bringing WASI to the Browsers
 * Make easy to plug different filesystems
 * Provide a type-safe api using Typescript
 * Providing multiple output targets to support both browsers and node
 * The API is adapted to the Node-WASI API: https://github.com/nodejs/wasi/blob/wasi/lib/wasi.js

This is the original MIT license below:

Copyright 2019 Gus Caplan

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to
deal in the Software without restriction, including without limitation the
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
IN THE SOFTWARE.