go-littr VS quickjs-emscripten

If you're interested in Go, I develop such a project and the plumbing required for it.

The code is at https://github.com/mariusor/go-littr and you can check it out at https://brutalinks.tech

For people favouring to the old reddit interface more, I created another federated alternative: https://github.com/mariusor/go-littr (with an example instance at https://brutalinks.tech).

Sadly it received less publicity and mind share than lemmy, so not everything might be up to the expectations of the HN crowd.

The code is on github: https://github.com/mariusor/go-littr An example is at: https://littr.me Status: not done.

Considering it's received HN's kiss-of-death, perhaps a pointer to the code is useful: https://github.com/mariusor/go-littr

If you're interested in another option to lotide, I'm working on a very similar project to it, called brutalinks. You can check it out an example instance at https://brutalinks.tech. The code is on github and sourcehut.

I started a go project to create a link aggregator similar to HN and old reddit, but built on top of ActivityPub.

It's targeted at small to medium communities, but at the same time it can reach outward through the federation mechanism that ActivityPub provides. Outside of immediate support to intercommunicate with other instances of its own platform, it will handle interactions from the larger fediverse at large: Mastodon, Pleroma, Pixelfed, etc.

Currently this is a one man project, namely me, and I would welcome support in any area that people could help: development, design, documentation, graphics, copy, etc.

The project can be found at https://github.com/mariusor/go-littr, and if anyone is interested there is a mailing list where people can get in touch: https://lists.sr.ht/~mariusor/activitypub-go

Some details about the project can be found on its wiki: https://man.sr.ht/~mariusor/go-activitypub/brutalinks/index....

https://littr.me/ is another federated reddit-like project under development, a "link aggregator" as they call it. https://github.com/mariusor/go-littr

I see that people already recommended lemmy, but if you're looking for something closer to old reddit and hacker news I am working on https://github.com/mariusor/go-littr. An example instance is at https://littr.me

I'm building something that could help in this regard: https://github.com/mariusor/go-littr

It's a distillation of the early reddit into a discussion platform that speaks activitypub. This means that the goal is not to have "one site" to rule them all, but that communities can each create their own and then interact with others if they chose to.

An demo instance is at https://littr.me

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

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!

"Safely execute untrusted Javascript in your Javascript, and execute synchronous code that uses async functions" quickjs-emscripten, NPM

This maybe, as a start?

https://github.com/justjake/quickjs-emscripten

QuickJS Running in WebAssembly\ (17 comments)

The library was inspired by Figma’s blog posts about their plug-in system: https://github.com/justjake/quickjs-emscripten#background

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.

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...

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.