Karel Hrkal (kajacx) (Jun 28 2023 at 14:03): Karel Hrkal (kajacx) (Jun 28 2023 at 14:03):Hello, is it possible to use wit bindgen in the browser? This is actually two questions:
1) Is it possible to load and use WASM components that use the component model in the browser?
2) Is it possible to load and use "normal" WASM modules that use wit bidgen (but aren't using the component model) in the browser AND is it possible to load and use these modules (again, not using component model, only wit bindgen) in wasmtime and get wit-bindings?
The reason I ask is that I have a video game in Rust and I want to load mods using WASM modules. I also want to run the game on the web.
If I use the component model, then it's probably not going to work on the web, since I didn't find any way to get a WASM component to load and run on the web.
If, on the other hand, I use just wit bindgen without the component model, then I do not know how to load and tun the module from wasmtime, since the only tutorials on how to use wit bindgen I could find use the component model when used with wasmtime host.
Alex Crichton (Jun 28 2023 at 15:29):Is it possible to load and use WASM components that use the component model in the browser?
For this you'll want to check out the jco project
Is it possible to load and use "normal" WASM modules that use wit bidgen (but aren't using the component model) in the browser AND is it possible to load and use these modules (again, not using component model, only wit bindgen) in wasmtime and get wit-bindings?
Sort of and sort of not. Today this is technically possible as native compilers are outtping core wasm modules which are then wrapped up into components. There's, strictly speaking, nothing stopping you from taking that core wasm module and running it in a browser and then alternatively also taking the component and running it in Wasmtime.
I say "sort of not" though because this isn't really a supported workflow and will likely have a lot of gotchas and surprises and isn't how things are supposed to work. Instead a component is intended to be the "source of truth" and tooling like jco enables running that in a browser.
Karel Hrkal (kajacx) (Jun 28 2023 at 17:31):Ok, I guess I will not be able to avoid the component model. But I am having trouble with making jco work. I have a wasm component that I created from a wasm module that was using wit bindgen using this command:
wasm-tools component new plugin_rust.wasm -o component.wasm
This component.wasm file is working correctly in wasmtime runtime. But when I pass it to jco, like this:
jco transpile component.wasm -o out-dir
I get an error:
(jco transpile) ComponentError: failed to extract interface information from component
Caused by:
unknown component version: 0xd (at offset 0x0)
Any help?
Robin Brown (Jun 28 2023 at 17:33):This likely means that jco is still on version 0xc and doesn't know about the component model version you produced.
Robin Brown (Jun 28 2023 at 17:34):Although, that appears to have landed.
Robin Brown (Jun 28 2023 at 17:34):https://github.com/bytecodealliance/jco/pull/86
Robin Brown (Jun 28 2023 at 17:35):Are you using the latest version of jco?
Karel Hrkal (kajacx) (Jun 28 2023 at 17:57):Kyle Brown said:
Are you using the latest version of jco?
I have version 0.7.0. How do i upgrade to a newer version?
Karel Hrkal (kajacx) (Jun 28 2023 at 18:08):Never mind, I got the new version, but now I have another error. My wit file looks like this:
package example:protocol
world my-world {
import print: func(msg: string)
export run: func()
}
And the first line of the generated component.js file is trying to import the print function:
import import print from 'print';
And it results in an error:
Uncaught SyntaxError: import is an invalid identifier
Can I generate proper TS bindings that would require me to provide the imported "print" function?
The current exported TS bindings only have the exported run function:
export function run(): void;
Alex Crichton (Jun 28 2023 at 18:10):It may be the case that jco hasn't upgraded from 0xc to 0xd, although @Guy Bedford would know for sure
Guy Bedford (Jun 28 2023 at 18:11):@Karel Hrkal if you want to provide the "print" function you can use the --instantiation flag option
Robin Brown (Jun 28 2023 at 18:21):@Alex Crichton the PR I link above says that it has
Alex Crichton (Jun 28 2023 at 18:22):oh oops sorry missed that
Karel Hrkal (kajacx) (Jun 28 2023 at 18:33):Guy Bedford said:
Karel Hrkal if you want to provide the "print" function you can use the
--instantiationflag option
Ok, that mostly works, but there are few problems.
First, the "print" function is named "default" for some reason in the generated bindings:
export interface ImportObject {
default(msg: string): void,
}
Second, there is a syntax error when getting this imported function, in the generated "component.js" file:
const const print = imports.default;
Removing the extra "const" makes it work correctly. I'm assuming I should create a bug issue on jco's github?
Guy Bedford (Jun 28 2023 at 18:42):@Karel Hrkal that would be great if you could post a bug, I'll look into it further
Guy Bedford (Jun 28 2023 at 19:57):@Karel Hrkal I've released jco@0.9.3 which should fix your issues
Karel Hrkal (kajacx) (Jun 29 2023 at 10:58):Guy Bedford said:
Karel Hrkal I've released jco@0.9.3 which should fix your issues
Yes, the "double const" issue is resolved, many thanks. The "import" function is still named "default" in the import object, but changing that would be a breaking change.
Notification Bot (Jul 01 2023 at 08:14):Karel Hrkal has marked this topic as resolved.
Karel Hrkal (kajacx) (Jul 02 2023 at 14:33):Hello @Guy Bedford, I think there are more problems when you have more than one import. I have created a new issue on github: https://github.com/bytecodealliance/jco/issues/103
Last updated: Dec 23 2024 at 12:05 UTC