Manganis

Manganis is a tool for submitting assets and native source files to the program linker. It makes it easy to self-host assets and native plugins that are distributed throughout your libraries.

Assets

Including assets is as simple as using the asset!() macro:

use manganis::{Asset, asset};
const STYLE: Asset = asset!("/assets/style.css");

After cargo builds your app, the asset path is embedded directly in the data section. A tool like the Dioxus CLI can extract this metadata and post-process these assets.

use manganis::{ImageFormat, Asset, asset, ImageSize, AssetOptions};
// You can collect arbitrary files. Absolute paths are resolved relative to the package root
const _: Asset = asset!("/assets/script.js");

// You can collect images which will be automatically optimized
pub const PNG_ASSET: Asset =
    asset!("/assets/image.png");
// Resize the image at compile time to make the assets smaller
pub const RESIZED_PNG_ASSET: Asset =
    asset!("/assets/image.png", AssetOptions::image().with_size(ImageSize::Manual { width: 52, height: 52 }));
// Or convert the image at compile time to a web friendly format
pub const AVIF_ASSET: Asset = asset!("/assets/image.png", AssetOptions::image().with_format(ImageFormat::Avif));

option_asset

If you have assets that may not always be bundled, you can fall back gracefully with option_asset!:

use manganis::{Asset, asset, option_asset};
const REQUIRED: Asset = asset!("/assets/style.css");
const OPTIONAL: Option<Asset> = option_asset!("/assets/missing.css");

JavaScript assets

The CLI auto-detects whether each .js asset is an ES module (top-level import/export or import.meta) or a classic script and processes it accordingly.

• with_minify(true) (default): the file is minified in place. Classic scripts are minified verbatim with their format preserved (no IIFE re-wrapping). ES modules are minified and bundled — local relative imports are inlined into a single ESM file, while http:// / https:// imports remain as external import statements for the browser to resolve at runtime.
• with_minify(false): the file is copied byte-for-byte. Use this when shipping pre-built third-party libraries you do not want re-processed.
• with_static_head(true): appends a <script> tag to the document head pointing at the asset. The CLI emits <script type="module" ...> when the file is detected (or declared) as an ES module, and a classic <script> otherwise.
• with_preload(true): emits a <link rel="preload" as="script"> for the asset.
• with_module(true): forces the file to be treated as an ES module even when auto-detection would say otherwise. Useful when you author a side-effect-only module without top-level import/export declarations. Files named *.mjs are always treated as modules; files named *.cjs are always treated as classic.

use manganis::{asset, Asset, AssetOptions};

// Vendored UMD library: copy verbatim, emitted as a classic <script>.
const SWEETALERT: Asset = asset!(
    "/assets/sweetalert2.all.min.js",
    AssetOptions::js().with_minify(false).with_static_head(true)
);

// Authored ES module with local imports: auto-detected from the top-level
// `import`/`export`, bundled and minified into a single ESM file, emitted as
// `<script type="module">`.
const APP: Asset = asset!(
    "/assets/app.js",
    AssetOptions::js().with_static_head(true)
);

Native FFI Bindings

Manganis provides the #[ffi] attribute macro for generating direct FFI bindings between Rust and native platforms (Swift/Kotlin). See the geolocation-native-plugin example for usage.