Unlock the Power of Deno Plugins with Rust

Why Choose Rust for Deno Plugins?

Rust plugins offer superior performance and access to a vast array of tools, making them ideal for heavy tasks like image processing. By leveraging Rust’s high-quality crates, you can expand the Deno ecosystem and create plugins that cater to specific needs.

Plugin Project Structure

The plugin project structure mirrors that of a standard Deno module. We’ll use a boilerplate to get started, which includes a Rust project in the native directory and a Deno module in the root.

Building a Rust Project

The Rust project compiles a dynamic library that’s loaded by the Deno runtime. The compiled file type and name vary depending on the operating system. Our boilerplate supports Linux, macOS, and Windows.

Adding Rust Code

Let’s create a PNG optimizer using the oxipng crate. Every Deno plugin must export the denoplugininit function and register all exported methods. We’ll use the #[no_mangle] attribute to ensure the function name remains unchanged.

#[no_mangle]
pub extern "C" fn denoplugininit() {
    // Register exported methods
}

Creating the Optimizer Function

Each exported function has a specific signature, and Deno plugins can only export functions. These functions can be sync or async, depending on the return type. We’ll create an optimizer function that takes a file as input, processes it, and returns the result as a Box.

#[no_mangle]
pub extern "C" fn optimize_image(file: &str) -> Box<[u8]> {
    // Optimize image logic
    // Return optimized image as a Box
}

Loading a Rust Plugin in Deno

Now that our plugin is compiled, let’s load it using Deno. We’ll use the openPlugin method to load the plugin and the ops method to get the method identifier. The dispatch function is used to run the code exported by the native plugin.

const plugin = await Deno.openPlugin("path/to/plugin");
const ops = plugin.ops();
const optimizer = ops.optimize_image;

const result = await optimizer("path/to/image.png");
console.log(result);

Writing Async Plugins

To avoid blocking the main thread, Deno allows you to return a future from the native function. We’ll create a future using the async block and return it as a boxed future. Deno handles the completion of the future and informs the Deno side of the plugin.

#[no_mangle]
pub extern "C" fn optimize_image_async(file: &str) -> Box<Future<Result<&[u8], std::io::Error>>> {
    async move {
        // Optimize image logic
        // Return optimized image as a Future
    }.boxed()
}

Unlocking the Full Potential of Deno Plugins

By leveraging Rust’s ecosystem and creating plugins, you can expand the Deno ecosystem and access a wide range of tools. Whether it’s image processing, database connectors, or more, Rust plugins offer unparalleled flexibility and performance.

• Image processing: Use Rust crates like oxipng to optimize images.
• Database connectors: Create plugins to interact with databases like PostgreSQL or MySQL.
• And more: Explore the vast ecosystem of Rust crates to unlock new possibilities.