Greenhorn

Write desktop and web applications in pure server-side rust

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Greenhorn is a rust library for building desktop and web applications with web technologies in (almost) pure rust.

This is accomplished by separating the application into a server-side process (the backend) and web view implemented in javascript (the frontend). While most HTML-based desktop applications leave state synchronization up to the application logic, this library synchronizes its state at DOM-level. Thus, the user may implement the application logic purely in the backend using rust. This facilitates the integration of a desktop GUI with system services and simplifies application development considerably.

Features

• Elm-like architecture
• Components support fine-grained update/render cycle
• Components are owned by the application state and may interact with each other using events
• Macros to write SVG and HTML in-line with Rust code
• Most tasks can be accomplished using pure-rust. If required, injecting and calling js is supported.
• Built-in performance metrics
• Spawning system dialogs
• This crate does not itself implement a frontend. A frontend is implemented in greenhorn_web_view. It makes use of web_view and tinyfiledialogs-rs.

Example

use greenhorn::prelude::*;
use greenhorn::html;

struct MyApp {
    text: String,
}

enum MyMsg {
    Clicked(DomEvent),
    KeyDown(DomEvent),
}

impl Render for MyApp {
    type Message = MyMsg;

    fn render(&self) -> Node<Self::Message> {
        html!(
            <div #my-app>
                <button type="button"
                        @keydown={MyMsg::KeyDown}
                        @mousedown={MyMsg::Clicked}>
                    {&self.text}
                </>
            </>
        ).into()
    }
}

impl App for MyApp {
    fn update(&mut self,msg: Self::Message,ctx: Context<Self::Message>) -> Updated {
        match msg {
            MyMsg::Clicked(evt) => self.text = "Button clicked!".into(),
            MyMsg::KeyDown(evt) => self.text = "Button keypress!".into()
        }
        Updated::yes()
    }

}

Acknowledgments

The concpet of this library is not at all new. It was already implemented before at least by the Threepenny-GUI library. The API was inspired by the many great rust frontend libraries:

• Yew
• Seed-rs