Use C ABI files (zig, rust, c/c++, c#, nim, kotlin...)

If you need to utilize files from different C ABI languages (Zig, Rust, C/C++, C#, Nim, Kotlin, etc.), you can achieve this as follows:

Create Your Zig, Rust, or Other File:

Zig:

// add.zig
pub export fn add(a: i32, b: i32) i32 {
  return a + b;
}

or with Rust:

// add.rs
#[no_mangle]
pub extern "C" fn add(a: isize, b: isize) -> isize {
    a + b
}

If you are using node or deno as output, this documentation does not apply. You need to find the equivalent in the specific JS runtime.

Compile Your Files

You need to compile it before using it in your Brisa app.

Zig:

zig build-lib add.zig -dynamic -OReleaseFast

or with Rust:

rustc --crate-type cdylib add.rs

Then, we need to move the generated files inside the prebuild folder.

This prebuild folder is used during brisa dev and brisa build where all the prebuild files are copied inside build/prebuild, to be able to use them later in runtime.

Example of script inside package.json to compile inside prebuild folder:

{
  "scripts": {
    "dev": "brisa dev",
    "build": "brisa build",
    "start": "brisa start",
    "build:zig": "cd prebuild && bun run build:zig:for-your-computer && bun run build:zig:docker:oven/bun && cd ..",
    "build:zig:for-your-computer": "zig build-lib ../src/zig/add.zig -dynamic -OReleaseFast",
    "build:zig:docker:oven/bun": "zig build-lib ../src/zig/add.zig -dynamic -OReleaseFast -target x86_64-linux-musl"
  }
}

If you do not have the prebuild folder you must create it.

Create a JS/TS Bridge

Develop a JavaScript/TypeScript file to bridge to the compiled file.

// src/utils/add.ts
import { dlopen, FFIType, suffix } from "bun:ffi";
import path from "node:path";

const compileFilePath = path.join(
  // You can use BRISA_BUILD_FOLDER env to access to the build folder
  Bun.env.BRISA_BUILD_FOLDER,
  // "prebuild" folder during build time is copied inside the build folder
  "prebuild",
  // `suffix` is either "dylib", "so", or "dll" depending on the platform
  // you don't have to use "suffix", it's just there for convenience
  `libadd.${suffix}`,
);

const lib = dlopen(compileFilePath, {
  add: {
    args: [FFIType.i32, FFIType.i32],
    returns: FFIType.i32,
  },
});

export default lib.symbols.add;

Ensure correct typing for the args and the return.

Access the environment variable BRISA_BUILD_FOLDER via process.env.BRISA_BUILD_FOLDER or Bun.env.BRISA_BUILD_FOLDER. This represents the path to the build folder, where the prebuild files are located.

Bun.env.BRISA_BUILD_FOLDER works in development and production.

Consume it in Your Server Code

Now, you can use it in any server file: components, layout, middleware, API, response headers, etc.

// src/pages/index.tsx
import add from "@/utils/add";

export default function HomePage() {
  return <div>5+5 is {add(5, 5)}</div>;
}

For more details, such as dealing with pointers, refer to Bun's FFI documentation.