Rust调用JS函数(很方便)

从 JavaScript 打印

fn main() {
    js_sandbox::eval_json("console.log('Hello Rust from JS')").expect("JS runs");
}

调用一个JS函数

triple()一个非常基本的应用程序从 Rust调用一个 JavaScript 函数。它传递一个参数并接受一个返回值，两者都通过 JSON 序列化：

use js_sandbox::{Script, AnyError};

fn main() -> Result<(), AnyError> {
    let js_code = "function sub(a, b) { return a - b; }";
    let mut script = Script::from_string(js_code)?;

    let result: i32 = script.call("sub", (7, 5))?;

    assert_eq!(result, 2);
    Ok(())
}

序列化 JSON 对象 (Rust -> JS) 并格式化字符串 (JS -> Rust) 的示例：

use js_sandbox::{Script, AnyError};
use serde::Serialize;

#[derive(Serialize)]
struct Person {
    name: String,
    age: u8,
}

fn main() -> Result<(), AnyError> {
    let src = r#"
        function toString(person) {
            return "A person named " + person.name + " of age " + person.age;
        }"#;

    let mut script = Script::from_string(src)
        .expect("Initialization succeeds");

    let person = Person { name: "Roger".to_string(), age: 42 };
    let result: String = script.call("toString", (person,)).unwrap();

    assert_eq!(result, "A person named Roger of age 42");
    Ok(())
}

加载 JS 文件

use js_sandbox::Script;

fn main() {
    let mut script = Script::from_file("script.js").expect("Load + init succeeds");
    // or, at compile time:
    let code: &'static str = include_str!("script.js");
    let mut script = Script::from_string(code).expect("Init succeeds");

    // use script as usual
}

可以初始化有状态的 JS 脚本，然后使用函数随着时间的推移修改该状态。此示例在两次调用中附加一个字符串，然后在第三次调用中获取结果

use js_sandbox::{Script, AnyError};

fn main() -> Result<(), AnyError> {
    let src = r#"
        var total = '';
        function append(str) { total += str; }
        function get()       { return total; }"#;

    let mut script = Script::from_string(src)?;

    let _: () = script.call("append", ("hello",))?;
    let _: () = script.call("append", (" world",))?;
    let result: String = script.call("get", ())?;

    assert_eq!(result, "hello world");
    Ok(())
}

使用超时调用脚本

JS 代码可能包含长时间或永远运行的循环，这些循环会阻塞 Rust 代码。可以设置一个超时，之后 JS 脚本执行被中止。

use js_sandbox::{Script, AnyError};

fn main() -> Result<(), AnyError> {
    use std::time::Duration;
    let js_code = "function run_forever() { for(;;){} }";
    let mut script = Script::from_string(js_code)?
        .with_timeout(Duration::from_millis(1000));

    let result: Result<String, AnyError> = script.call("run_forever", ());

    assert_eq!(
        result.unwrap_err().to_string(),
        "Uncaught Error: execution terminated".to_string()
    );

    Ok(())
}

将以下内容添加到项目的 Cargo.toml 文件中

[dependencies]
js-sandbox="0.2.0-rc.0"