/wasm_renderer

Primary LanguageRust

An application that renders text:

  • written in Rust
  • plugin-based design
  • plugins are wasm modules

Based on wasmlink demo of the wit-bindgen project.

Goal

A Rust plugin-based app that renders text, where the plugins are wasm modules.

Design

  • The renderer API is defined by renderer.wit.
  • The app will search for plugins in the plugins directory.

Building

Let us build the plugin that renders markdown into html.

Prerequisites

We use cargo-wasi to compile the plugin. Install it using cargo:

$ cargo install cargo-wasi

Building the markdown plugin

The renderer.wit defines the structure of a plugin: a render function that takes a string (the Markdown) as an argument and returns a string (the rendered HTML).

To build the markdown plugin:

  • Go to the markdown directory.
  • Build using cargo wasi build

Adding the plugin to the app

Take the resulting markdown.wasm file (in markdown\target\wasm32-wasi\debug\markdown.wasm) and put it into app\plugins, so that the app can find it. You may run something like cp markdown\target\wasm32-wasi\debug\markdown.wasm app\plugins.

Running

Let us run our app. (For now it will run only the markdown plugin)

  • Go to the app directory.
  • Use cargo run.

Notes

  • Check that markdown.wasm is under the plugins folder.
  • Note that the renderer.wit is also needed for the app to interpret this wasm file.