2 stable releases
6.0.3 | Feb 14, 2024 |
---|---|
6.0.2 | Feb 13, 2024 |
#5 in #n-api
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ohos-node-bindgen
兼容华为鸿蒙ArkTS N-API
如何实现兼容
在原作者伟大作品的基础上,我做了三项工作使node-bindgen
支持华为鸿蒙ArkTS N-API
开发
- 将封装了nodejs N-API的内部子工程
nj-sys
·替换为·包装了【鸿蒙ArkTS N-API
】的外部依赖项oh-napi-sys。- 一方面,
node-bindgen
原作者的代码设计非常科学合理,所以对核心模块*-sys crate
的替换工作很省心。 - 另一方面,【鸿蒙
ArkTS N-API
】与nodejs N-API
的相似度极高。所以,模块替换后的适配工作量少之又少。
- 一方面,
- 添加【编译条件】 — 这算是一处适配点
- 原因:【
C
无符号长整类型unsigned long
】在鸿蒙armv7
架构上是32bit
,而在鸿蒙aarch64
与x86_64
架构上却是64bit
。所以,若既不搞【条件编译】又不预备多套代码,那么rustc
就会交叉编译失败。感谢Rust
的【条件编译】语言支持,让Cpp
开发都哭去吧! - 打广告了:在该基建之上做鸿蒙
ArkTS N-API
开发的中国同胞们就不用再分心考虑这类【架构差异】的技术细节了。这些破事实在太糟心!
- 原因:【
- 修改包名从
node-bindgen
至ohos-node-bindgen
。
就目前而言,【鸿蒙ArkTS N-API
】与nodejs N-API
大约是95%
相似。但是,我相信随着【鸿蒙操作系统】的后续发展,ArkTS N-API
会引入越来越多与外国同类产品(比如,nodejs / Deno
)不同的内容。
ohos-node-bindgen
用法
新/旧用法差异不在代码调用,而全部集中于Cargo.toml
工程配置中
-
不再需要向
[build-dependencies]
配置表添加node-bindgen = { version = "6.0", default-features = false, features = ["build"] }
依赖项了,因为【编译时链接】已完全委托给外部依赖项oh-napi-sys完成了。 -
输出链接库的编码格式不再是
cdylib
,而是dylib
。即,[lib] crate-type = ["dylib"]
ohos-node-bindgen
还不能被直接使用
起因是ohos-node-bindgen
的间接依赖项socket2 v0.4.10
不兼容【华为鸿蒙操作系统】(— 别急,有得解)。依赖图如下
socket2 v0.4.10
├── async-io v1.13.0
│ ├── async-std v1.12.0
│ │ └── fluvio-future v0.6.2
│ │ └── nj-core v6.0.1
│ │ └── ohos-node-bindgen v6.0.2
虽然依赖“血缘”关系隔了四层之远,但它仍会阻塞交叉编译。我亲测的解决方案:
-
【我已做,大家不用做】我已经
fork
了socket2@0.4.x分支,并解了其对【华为鸿蒙操作系统】的兼容缺陷。所以, -
大家直接克隆我的
fork
版本至本地硬盘,和切分支至v0.4.x
git clone git@github.com:stuartZhang/socket2.git git checkout v0.4.x
-
重写(
Override
)调用端工程的【依赖图】,以指示Cargo
优先加载本地的socket2:0.4.10
依赖项,而不是从crates.io
下载。即,向Cargo.toml
文件增补如下配置表[dependencies] socket2 = "0.4.10" [patch.crates-io] socket2 = { path = "<指向 socket2 本地克隆复本的完整路径>" }
然后,就能绕过线上的残次socket2 crate
和成功交叉编译了。
Features
- Easy: Just write idiomatic Rust code, node-bindgen take care of generating Node.js FFI wrapper codes.
- Safe: Node.js arguments are checked automatically based on Rust types.
- Async: Support Async Rust. Async codes are translated into Node.js promises.
- Class: Rust struct can be accessed using Node.js classes.
- Stream: Implement Node.js stream using Rust
- N-API: Use Node.js N-API, which means you don't have to recompile your module.
Compatibility with Node.js version
This project uses the v8 of Node N-API. Please see following compatibility matrix.
Following OS are supported:
- Linux
- MacOs
- Windows
Why node-bindgen?
Writing native node-js requires lots of boilerplate code. Node-bindgen generates external "C" glue code from rust code, including native module registration. node-bindgen make it writing node-js module easy and fun.
Getting started
CLI Installation
Install nj-cli command line, which will be used to generate the native library.
cargo install nj-cli
This is a one time step.
Configuring Cargo.toml
Add two dependencies to your projects' Cargo.toml
.
Add node-bindgen
as a regular dependency (as below):
[dependencies]
node-bindgen = { version = "6.0" }
Then update crate type to dylib
to generate node.js compatible native module:
[lib]
crate-type = ["dylib"]
Finally, add build.rs
at the top of the project with following content:
fn main() {
ohos_node_bindgen::build::configure();
}
Example
Here is a function that adds two numbers. Note that you don't need to worry about JS conversion.
use ohos_node_bindgen::derive::node_bindgen;
/// add two integer
#[ohos_node_bindgen]
fn sum(first: i32, second: i32) -> i32 {
first + second
}
Building native library
To build node.js library, using nj-cli
to build:
nj-cli build
This will generate Node.js module in "./dist" folder.
To build a release version:
nj-cli build --release
Watching ./src
for Changes
While developing your native module, you may want to watch for file changes and run a command when a change occurs, for example cargo check
or cargo build
.
For this, we can use nj-cli watch
.
nj-cli watch
installs [if it does not exist] and passes arguments to cargo watch
. By default, nj-cli watch
will run cargo check
against your ./src
files.
To see all available methods for nj-cli watch
, run the following command:
nj-cli watch -- --help
Using in Node.js
Then in the Node.js, rust function can be invoked as normal node.js function:
$ node
Welcome to Node.js v18.18.0.
Type ".help" for more information.
> let addon = require('./dist');
undefined
> addon.sum(2,3)
5
>
Features
Function name or method can be renamed instead of default mapping
#[node_bindgen(name="multiply")]
fn mul(first: i32,second: i32) -> i32 {
first * second
}
Rust function mul is re-mapped as multiply
Optional argument
Argument can be skipped if it is marked as optional
#[ohos_node_bindgen]
fn sum(first: i32, second: Option<i32>) -> i32 {
first + second.unwrap_or(0)
}
Then sum can be invoked as
sum(10)
or sum(10,20)
Callback
JS callback are mapped as Rust closure.
#[ohos_node_bindgen]
fn hello<F: Fn(String)>(first: f64, second: F) {
let msg = format!("argument is: {}", first);
second(msg);
}
from node:
let addon = require('./dist');
addon.hello(2,function(msg){
assert.equal(msg,"argument is: 2");
console.log(msg); // print out argument is 2
});
Callback are supported in Async rust as well.
Support for Async Rust
Async rust function is mapped to Node.js promise.
use std::time::Duration;
use flv_future_aio::time::sleep;
use ohos_node_bindgen::derive::node_bindgen;
#[ohos_node_bindgen]
async fn hello(arg: f64) -> f64 {
println!("sleeping");
sleep(Duration::from_secs(1)).await;
println!("woke and adding 10.0");
arg + 10.0
}
let addon = require('./dist');
addon.hello(5).then((val) => {
console.log("future value is %s",val);
});
Struct serialization
Structs, including generic structs, can have have the to-JS conversion boilerplate autogenerated.
Just apply the node_bindgen
macro to your struct:
#[ohos_node_bindgen]
struct MyJson {
some_name: String,
a_number: i64
}
#[ohos_node_bindgen]
fn my_json() -> MyJson {
MyJson {
some_name: "John".to_owned(),
a_number: 1337
}
}
let addon = require('./dist');
assert.deepStrictEqual(addon.my_json(), {
someName: "John",
aNumber: 1337
});
Note that the fields must implement
ohos_node_bindgen::core::TryIntoJs
themselves.
Any references must also implement Clone
.
Field names will be converted to camelCase.
Enums
Enums will also have their JS representation autogenerated with the help of ohos_node_bindgen
:
#[ohos_node_bindgen]
enum ErrorType {
WithMessage(String, usize),
WithFields {
val: usize
},
UnitErrorType
}
#[ohos_node_bindgen]
fn with_message() -> ErrorType {
ErrorType::WithMessage("test".to_owned(), 321)
}
#[ohos_node_bindgen]
fn with_fields() -> ErrorType {
ErrorType::WithFields {
val: 123
}
}
#[ohos_node_bindgen]
fn with_unit() -> ErrorType {
ErrorType::UnitErrorType
}
assert.deepStrictEqual(addon.withMessage(), {
withMessage: ["test", 321n]
});
assert.deepStrictEqual(addon.withFields(), {
withFields: {
val: 123n
}
});
assert.deepStrictEqual(addon.withUnit(), "UnitErrorType")
Tuple variants will be converted into lists, struct variants converted to objects, and unit variants converted into strings matching the variant's name in PascalCase. Generics and references are supported, with the same caveats as for structs.
JavaScript class
JavaScript class is supported.
struct MyClass {
val: f64,
}
#[ohos_node_bindgen]
impl MyClass {
#[node_bindgen(constructor)]
fn new(val: f64) -> Self {
Self { val }
}
#[ohos_node_bindgen]
fn plus_one(&self) -> f64 {
self.val + 1.0
}
#[node_bindgen(getter)]
fn value(&self) -> f64 {
self.val
}
}
let addon = require('./dist');
const assert = require('assert');
let obj = new addon.MyObject(10);
assert.equal(obj.value,10,"verify value works");
assert.equal(obj.plusOne(),11);
There are more features in the examples folder.
Preparing npm packages
Node module generated with node-bindgen
can be used directly in any node JS project, just copied index.node
into it. But in case of direct access to a module IDE will not highlight available functions, classes etc. Usually, this is not comfortable and makes the risks of potential bugs higher as soon as the public API of the node module is changed.
To create a full-fledged npm package with TypeScript types definitions and all necessary JavaScript wrappers can be used a crate tslink.
tslink
crate generates files *.d.ts
, *.js
and package.json
with a description of the npm module. Such package could be integrated into an end-project with minimal effort.
In addition, because tslink
generates TypeScript types definitions, any changes on the native node module (index.node
) will be highlighted by TypeScript
compiler and it makes the risk of bugs (related to changed API or public data types) much lower.
For example,
#[macro_use] extern crate tslink;
use tslink::tslink;
use ohos_node_bindgen::derive::node_bindgen;
struct MyScruct {
inc: i32,
}
#[tslink(class)]
#[ohos_node_bindgen]
impl MyScruct {
#[tslink(constructor)]
#[node_bindgen(constructor)]
pub fn new(inc: i32) -> Self {
Self { inc }
}
#[tslink(snake_case_naming)]
#[ohos_node_bindgen]
fn inc_my_number(&self, a: i32) -> i32 {
a + self.inc
}
}
Would be represented (*.d.ts
) as
export declare class MyStruct {
constructor(inc: number);
incMyNumber(a: number): number;
}
Pay your attention, call of #[tslink]
should be always above of call #[ohos_node_bindgen]
.
Also, please note, node-bindgen
by default applies snake case naming to methods. You should use #[tslink(snake_case_naming)]
to consider this moment (see more on crate page).
tslink
requires a configuration in Cargo.toml
(section [tslink]
) of the root of your project. A configuration should include a valid path to the native node module. By default node-bindgen
creates index.node
in ./dist
folder of your root
.
File: ./Cargo.toml
(in a root
of project):
[project]
...
[lib]
...
[tslink]
node = "./dist/index.node"
Full example of usage tslink
and node-bindgen
is here.
See more API documentation on a tslink
crate page.
Note. The node-bindgen's developers are not responsible for the correctness of the work tslink crate. All possible issues and feature requests related to tslink should be addressed to tslink's developers.
Contributing
If you'd like to contribute to the project, please read our Contributing guide.
License
This project is licensed under the Apache license.
Dependencies
~0–15MB
~142K SLoC