Examples use `rquickjs::bind` but that's not available since 0.4.0

[ekaitz-zarraga]

Hi,

I have been trying to make some native modules and the rquickjs::bind macro is not available since 0.4.0.

What's the way to do that right now? Is there any other macro I'm missing?

[ekaitz-zarraga]

Okay I found it should be something like: Module::declare_def could you please help me update the examples?

Are more examples welcome?

[ekaitz-zarraga]

I managed to write this one, but there are several things I dislike.

• How should I return the errors from the fetch_url function without using anyhow and actually having some proper description?
• Are you ok with adding an example that requires reqwest? I think it's an interesting usecase for people to have as a reference.

use std::fs;
use anyhow::{Result, anyhow};
use rquickjs::{ Context, Runtime, CatchResultExt };

#[rquickjs::module(rename_vars = "camelCase")]
mod native_api {
    #[rquickjs::function]
    pub fn fetch_text(url: String) -> Result<String, rquickjs::Error> {
        let body = reqwest::blocking::get(url)
            .map_err(|e| rquickjs::Error::Exception)?
            .text()
            .map_err(|e| rquickjs::Error::Exception)?;
        Ok(body)
    }

    #[rquickjs::function]
    pub fn print(s: String) {
        println!("{s}");
    }
}

fn main() -> Result<()>{
    let rt = Runtime::new()?;
    let ctx = Context::full(&rt)?;

    let script = fs::read_to_string("file.js")?;

    let r = ctx.with::<_, Result<()>> (|ctx| {
        rquickjs::Module::declare_def::<js_native_api, _>(ctx.clone(), "native_api").unwrap();
        let m = rquickjs::Module::declare(ctx.clone(), "script", script.clone())
            .catch(&ctx)
            .map_err(|e| anyhow!("JS error: {}", e))?;
        let (_m, m_promise) = m
            .eval()
            .catch(&ctx)
            .map_err(|e| anyhow!("JS error: {}", e))?;
        () = m_promise.finish()
            .catch(&ctx)
            .map_err(|e| anyhow!("JS error: {}", e))?;
        Ok(())
    });

    let _ = r.map_err(|r| eprintln!("{}", r));

    Ok(())
}

import {print, fetch_text} from "native_api";

print( fetch_text("http://rust.org") );

[AtaLuZiK]

Hey! You can use the Ctx::throw method to throw any value as an exception into the script:

    #[rquickjs::function]
    pub fn fetch_text(ctx: Ctx<'_>, url: String) -> Result<String, rquickjs::Error> {
        let exception = Object::new(ctx.clone())?;
        exception.set("message", "Some message")?;
        exception.set("code", 123)?;
        Err(ctx.throw(exception.into()))
    }

which can then be caught within the script:

import {print, fetch_text} from "native_api";

try {
  print( fetch_text("http://rust.org") );
} catch (e) {
  print(`Code: ${e.code}`);
  print(`Message: ${e.message}`);
}

I think your example is very helpful for people who are new to rquickjs.

[ekaitz-zarraga]

Thank you for the explanation.
I knew about throw but I didn't know that you could pass the context to the functions!

I think the docs should be more clear about that, and this improved example could be added somewhere. I also believe it could be useful for newcomers.