quickjs-emscripten
memory64
quickjs-emscripten | memory64 | |
---|---|---|
21 | 7 | |
1,130 | 179 | |
- | 2.2% | |
9.4 | 8.5 | |
21 days ago | 2 days ago | |
TypeScript | WebAssembly | |
GNU General Public License v3.0 or later | GNU General Public License v3.0 or later |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
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For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
quickjs-emscripten
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New QuickJS Release
Based on your comment below I think you figured out the difference - but if you're looking to execute JS, you can pick between ShadowRealm (where available, or using a polyfill) or my library quickjs-emscripten.
Pros of quickjs-emscripten over ShadowRealm:
- You can use quickjs today in any browser with WASM. ShadowRealm isn't available yet, and polyfills have had security issues in the past. See https://www.figma.com/blog/an-update-on-plugin-security/
- In ShadowRealm eval, untrusted code can consume arbitrary CPU cycles. With QuickJS, you can control the CPU time used during an `eval` using an [interrupt handler] that's called periodically during the eval.
- In ShadowRealm eval, untrusted code can allocate arbitrary amounts of memory. With QuickJS, you can control both the [stack size] and the [heap size] available inside the runtime.
- quickjs-emscripten can do interesting things with custom module loaders and facades that allow synchronous code inside the runtime to call async code on the host.
Pros of ShadowRealm over QuickJS:
- ShadowRealm will (presumably?) execute code using your native runtime, probably v8, JavaScriptCore, or SpiderMonkey. Quickjs is orders of magnitude slower than JIT'd javascript performance of v8 etc. It's also slower than v8/JSC's interpreters, although not by a huge amount. See [benchmarks] from 2019.
- You can easily call and pass values to ShadowRealm imported functions. Talking to quickjs-emscripten guest code requires a lot of fiddly and manual object building.
- Overall the quickjs(-emscripten) API is verbose, and requires manual memory management of references to values inside the quickjs runtime.
[interrupt handler]: https://github.com/justjake/quickjs-emscripten/blob/main/doc...
[stack size]: https://github.com/justjake/quickjs-emscripten/blob/main/doc...
[heap size]: https://github.com/justjake/quickjs-emscripten/blob/main/doc...
[benchmarks]: https://bellard.org/quickjs/bench.html
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Extism Makes WebAssembly Easy
The thing I want to achieve with WebAssembly is still proving a lot harder than I had anticipated.
I want to be able to take strings of untrusted code provided by users and execute them in a safe sandbox.
I have all sorts of things I want this for - think custom templates for a web application, custom workflow automation scripts (Zapier-style), running transformations against JSON data.
When you're dealing with untrusted code you need a really robust sandbox. WebAssembly really should be that sandbox.
I'd like to support Python, JavaScript and maybe other languages too. I want to take a user-provided string of code in one of those languages and execute that in a sandbox with a strict limit on both memory usage and time taken (so I can't be crashed by a "while True" loop). If memory or time limit are exceeded, I want to get an exception which I can catch and return an error message to the user.
I've been exploring options for this for quite a while now. The furthest I've got was running Pyodide inside of Deno: https://til.simonwillison.net/deno/pyodide-sandbox
Surprisingly I've not found a good pattern for running a JavaScript interpreter in a WASM sandbox yet. https://github.com/justjake/quickjs-emscripten looks promising but I've not found the right recipe to call it from server-side Python or Deno yet.
Can Extism help with this? I'm confident I'm not the only person who's looking for a solution here!
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Node on Web. Use Nodejs freely in your browser with Linux infrastructure.
"Safely execute untrusted Javascript in your Javascript, and execute synchronous code that uses async functions" quickjs-emscripten, NPM
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Sandboxing JavaScript Code
This maybe, as a start?
https://github.com/justjake/quickjs-emscripten
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Hacker News top posts: Nov 20, 2022
QuickJS Running in WebAssembly\ (17 comments)
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QuickJS Running in WebAssembly
The library was inspired by Figma’s blog posts about their plug-in system: https://github.com/justjake/quickjs-emscripten#background
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Show HN: Run unsafe user generated JavaScript in the browser
If you need to call into user-generated Javascript synchronously or have greater control over the sandbox environment, you can use WebAssembly to run a Javascript interpreter: https://github.com/justjake/quickjs-emscripten#quickjs-emscr...
QuickJS in WebAssembly is much slower than your browser's native Javascript runtime, but possibly faster than async calls using postMessage. As an added bonus, it can make async functions in the host appear to be synchronous inside the sandbox using asyncify: https://emscripten.org/docs/porting/asyncify.html.
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Why Would Anyone Need JavaScript Generator Functions?
You can use One Weird Trick with generator functions to make your code "generic" over synchronicity. I use this technique to avoid needing to implement both sync and async versions of some functions in my quickjs-emscripten library.
The great part about this technique as a library author is that unlike choosing to use a Promise return type, this technique is invisible in my public API. I can write a function like `export function coolAlgorithm(getData: (request: I) => O | Promise): R | Promise`, and we get automatic performance improvement if the user's function happens to return synchronously, without mystery generator stuff showing up in the function signature.
Helper to make a function that can be either sync or async: https://github.com/justjake/quickjs-emscripten/blob/ff211447...
Uses: https://cs.github.com/justjake/quickjs-emscripten?q=yield*+l...
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Why Am I Excited About WebAssembly?
This seems like a pretty nice, recently enabled way of getting a sandboxed js environment: QuickJS compiled to WASM: https://github.com/justjake/quickjs-emscripten.
memory64
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Top 8 Recent V8 Updates
A completed implementation of memory64 for memory-hungry applications.
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Extism Makes WebAssembly Easy
Indeed, webassembly is moving extremely slowly. I started a project years ago expecting https://github.com/WebAssembly/memory-control/blob/main/prop... and https://github.com/WebAssembly/memory64 to be fixed at some point. Neither are yet, and the project still suffers from it to this day.
I think wasm is still great without these fixes, but I have lost confidence in the idea that wasm will reach its full potential any time soon.
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How Photoshop solved working with files larger than can fit into memory
It's in the works: https://github.com/WebAssembly/memory64
Starting with 32bit had some performance advantages because 64bit runtimes can use virtual memory shenanigans to implement bounds checking with zero overhead. In wasm64 they'll have to do explicit bounds checking instead.
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Transformers.js
Right - currently, everything runs using WASM (32-bit, with 64-bit coming soon [1,2]), and I plan to add support for WebGPU soon!
(WebGPU is the successor to WebGL, which is coming out in April 2023 [3])
[1] https://github.com/WebAssembly/memory64/issues/36#issuecomme...
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What was the rational for 32-bit memory addresses in WebAssembly? It seems very short-sighted, considering it only came out pretty recently in 2017
It shouldn't be a big surprise that a 64-bit pointer extension is out there and being worked on. The great thing about a VM is you can integrate major changes like this when they are needed and with the benefit of experience and hindsight. If the 4GB limit turns out to be restrictive then it can be lifted.
- Why Am I Excited About WebAssembly?
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Increasing Smart Contract Canister Memory Proposal is live for review
The goal of this proposal is to increase the amount of memory that canisters can access [eventually] bound only by the actual capacity of the subnet. Since, the Memory64 proposal is not standardized 1 yet and its implementation 1 in Wasmtime is not production ready yet, this proposal enables the increase by introducing a new stable memory API.
What are some alternatives?
wasmtime - A fast and secure runtime for WebAssembly
interface-types
wasmer - 🚀 The leading Wasm Runtime supporting WASIX, WASI and Emscripten
wizer - The WebAssembly Pre-Initializer
botnet - Multiplayer programming game using Rust and WebAssembly
rr - Record and Replay Framework
temporal-polyfill - A lightweight polyfill for Temporal, successor to the JavaScript Date object
go - The Go programming language
proposal-temporal - Provides standard objects and functions for working with dates and times.
iPlug2 - C++ Audio Plug-in Framework for desktop, mobile and web
component-sandbox-demo