rustyscript

Effortless JS Integration for Rust

This crate is meant to provide a quick and simple way to integrate a runtime javacript or typescript component from within rust.

• By default, the code being run is entirely sandboxed from the host, having no filesystem or network access.
  • It can be extended to include those capabilities and more if desired - please see the 'web' feature, and the runtime_extensions example
• Asynchronous JS code is supported (I suggest using the timeout option when creating your runtime)
• Loaded JS modules can import other modules
• Typescript is supported by default, and will be transpiled into JS for execution

Here is a very basic use of this crate to execute a JS module. It will:

• Create a basic runtime
• Load a javascript module,
• Call a function registered as the entrypoint
• Return the resulting value

use rustyscript::{json_args, Runtime, Module, Error};

let module = Module::new(
    "test.js",
    "
    rustyscript.register_entrypoint(
        (string, integer) => {
            console.log(`Hello world: string=${string}, integer=${integer}`);
            return 2;
        }
    )
    "
);

let value: usize = Runtime::execute_module(
    &module, vec![],
    Default::default(),
    json_args!("test", 5)
)?;

assert_eq!(value, 2);

Modules can also be loaded from the filesystem with Module::load or Module::load_dir if you want to collect all modules in a given directory.

If all you need is the result of a single javascript expression, you can use:

let result: i64 = rustyscript::evaluate("5 + 5").expect("The expression was invalid!");

Or to just import a single module for use:

use rustyscript::{json_args, import};
let mut module = import("js/my_module.js").expect("Something went wrong!");
let value: String = module.call("exported_function_name", json_args!()).expect("Could not get a value!");

There are a few other utilities included, such as rustyscript::validate and rustyscript::resolve_path

A more detailed version of the crate's usage can be seen below, which breaks down the steps instead of using the one-liner Runtime::execute_module:

use rustyscript::{json_args, Runtime, RuntimeOptions, Module, Error, Undefined};
use std::time::Duration;

let module = Module::new(
    "test.js",
    "
    let internalValue = 0;
    export const load = (value) => internalValue = value;
    export const getValue = () => internalValue;
    "
);

// Create a new runtime
let mut runtime = Runtime::new(RuntimeOptions {
    timeout: Duration::from_millis(50), // Stop execution by force after 50ms
    default_entrypoint: Some("load".to_string()), // Run this as the entrypoint function if none is registered
    ..Default::default()
})?;

// The handle returned is used to get exported functions and values from that module.
// We then call the entrypoint function, but do not need a return value.
//Load can be called multiple times, and modules can import other loaded modules
// Using `import './filename.js'`
let module_handle = runtime.load_module(&module)?;
runtime.call_entrypoint::<Undefined>(&module_handle, json_args!(2))?;

// Functions don't need to be the entrypoint to be callable!
let internal_value: i64 = runtime.call_function(&module_handle, "getValue", json_args!())?;

Utility Functions

These functions provide simple one-liner access to common features of this crate:

• evaluate; Evaluate a single JS expression and return the resulting value
• import; Get a handle to a JS module from which you can get exported values and functions
• resolve_path; Resolve a relative path to the current working dir
• validate; Validate the syntax of a JS expression

Crate features

• console (deno_console); Add the deno_console crate, providing console.* functionality from JS
• url (deno_url, deno_webidl); Provides the WebIDL, URL, and URLPattern APIs from within JS
• web = (deno_webidl, deno_web, deno_crypto, deno_fetch); Provides the Event, TextEncoder, TextDecoder, File, Web Cryptography, and fetch APIs from within JS
• default (console, url); Provides only those extensions that preserve sandboxing between the host and runtime
• no_extensions; Disable all optional extensions to the runtime
• all (console, url, web)

Please also check out @Bromeon/js_sandbox, another great crate in this niche

For an example of this crate in use, please check out lavendeux-parser

License: MIT OR Apache-2.0