lucasfernog / neon-serde

Simplify running rust in nodejs

Neon-serde

This crate is a utility to easily convert values between

A Handle<JsValue> from the neon crate and any value implementing serde::{Serialize, Deserialize}

Versions support

neon-serde is tested on node 8 10 12

Usage

neon_serde::from_value

Convert a Handle<js::JsValue> to a type implementing serde::Deserialize

neon_serde::to_value˚

Convert a value implementing serde::Serialize to a Handle<JsValue>

Export Macro example

The export! macro allows you to quickly define functions automatically convert thier arguments

#[macro_use]
extern crate neon;
#[macro_use]
extern crate neon_serde;
#[macro_use]
extern crate serde_derive;
extern crate serde_bytes;

#[derive(Deserialize)]
struct User {
    name: String,
    age: u16,
}

export! {

    /// Say hello based on a persons name
    fn say_hello(name: String) -> String {
        format!("Hello, {}!", name)
    }

    /// Say how old someone is
    fn greet(user: User) -> String {
        format!("{} is {} years old", user.name, user.age)
    }

    /// Say how old someone is, if they exist
    fn maybe_say_hello(user: Option<User>) -> Option<String> {
        user.map(greet)
    }

    /// Sorts the bytes in a string
    /// use `serde_bytes::ByteBuf` to return a `Buffer` in node
    /// a `Vec<u8>` will be an array
    fn sort_utf8_bytes(str: String) -> serde_bytes::ByteBuf {
        let mut bytes = str.into_bytes();
        bytes.sort();
        serde_bytes::ByteBuf::from(bytes)
    }

    /// using `serde_bytes::ByteBuf` will make passing an array
    /// of numbers an error
    ///
    /// note: `-> ()` is NOT optional
    fn expect_buffer_only(_buff: serde_bytes::ByteBuf) -> () {
        // code
    }

    /// using `Vec<u8>` not accept a buffer
    fn expect_array(_buff: Vec<u8>) -> () {
        // code
    }

    /// calculate fibonacci recursively
    fn fibonacci(n: i32) -> i32 {
        match n {
            1 | 2 => 1,
            n => fibonacci(n - 1) + fibonacci(n - 2)
        }
    }
}

Direct Usage Example

extern crate neon_serde;
extern crate neon;
#[macro_use]
extern crate serde_derive;

use neon::prelude::*;

#[derive(Serialize, Debug, Deserialize)]
struct AnObject {
    a: u32,
    b: Vec<f64>,
    c: String,
}

fn deserialize_something(mut cx: FunctionContext) -> JsResult<JsValue> {
    let arg0 = cx.argument::<JsValue>(0)?;

    let arg0_value :AnObject = neon_serde::from_value(&mut cx, arg0)?;
    println!("{:?}", arg0_value);

    Ok(JsUndefined::new().upcast())
}

fn serialize_something(mut cx: FunctionContext) -> JsResult<JsValue> {
    let value = AnObject {
        a: 1,
        b: vec![2f64, 3f64, 4f64],
        c: "a string".into()
    };

    let js_value = neon_serde::to_value(&mut cx, &value)?;
    Ok(js_value)
}

Limitations

Data ownership

All Deserialize Values must own all their data (they must have the trait serde::DererializeOwned)