Lib.rs

› Template engine | WebAssembly › UIBeam
#web-ui #html-template-engine #jsx #html

macro uibeam_macros

proc macros for UIBeam - A lightweight, JSX-style Web UI library for Rust

Owned by kanarus, ohkami-rs.

12 unstable releases (3 breaking)

Uses new Rust 2024

0.4.0 Dec 9, 2025
0.3.1 Nov 24, 2025
0.3.0 Aug 28, 2025
0.2.3 May 30, 2025
0.1.4 May 7, 2025

#18 in #html-template-engine


Used in uibeam

MIT license

105KB
1.5K SLoC

UIBeam

A lightweight, JSX-style Web UI library for Rust

License CI status crates.io
  • UI! : JSX-style template syntax with compile-time checks
  • Beam : Component System based on Rust structs

Features

  • Supports client component via island architecture in Wasm. (See Client Component section below)
  • Simply organized API and codebase.
  • Emits efficient template rendering avoiding redundant memory allocations as smartly as possible.
  • HTML completions and hovers in UI! by VSCode extension. ( search "uibeam" from extension marketplace )

Usage

[dependencies]
uibeam = "0.4"

When using uibeam just as a template engine, disabling client default feature is recommended to eliminate useless dependencies:

[dependencies]
uibeam = { version = "0.4", default-features = false }

UI! syntax

use uibeam::UI;

fn main() {
    let user_name = "foo";

    let style = "
        color: red; \
        font-size: 20px; \
    ";
    
    let ui: UI = UI! {
        <p class="hello" style={style}>
            "Welcome to the world of UIBeam!"
            <br>
            "こんにちは"
            <a
                class="user"
                style="color: blue;"
                data-user-id="123"
                href="https://example-chatapp.com/users/123"
            >
                "@"{user_name}"!"
            </a>
        </p>
    };

    println!("{}", uibeam::shoot(ui));
}

unsafely insert HTML string

raw string literal ( r#"..."# ) or unsafe block contents are rendered without HTML-escape :

use uibeam::UI;

fn main() {
    println!("{}", uibeam::shoot(UI! {
        <html>
            <body>
                /* ↓ wrong here: scripts are html-escaped... */

                <script>
                    "console.log('1 << 3 =', 1 << 3);"
                </script>

                <script>
                    {include_str!("index.js")}
                </script>

                /* ↓ scripts are NOT html-escaped, rendered as they are */

                <script>
                    r#"console.log('1 << 3 =', 1 << 3);"#
                </script>

                <script>
                    unsafe {include_str!("index.js")}
                </script>

                <script>
                    unsafe {"console.log('1 << 3 =', 1 << 3);"}
                </script>
            </body>
        </html>
    }));
}

conditional & iterative rendering

{} at node-position in UI! can render, in addition to Display-able values, any impl IntoIterator<Item = UI>. This includes Option<UI> or any other iterators yielding UIs !

use uibeam::{UI, Beam};

struct Task {
    id: u64,
    title: String,
    subtasks: Vec<String>,
    completed: bool,
}

fn main() {
    let t = Task {
        id: 42,
        title: "try uibeam".to_string(),
        subtasks: vec![],
        completed: false,
    };

    let ui = UI! {
        <div id={format!("task-{}", t.id)}>
            <h2>{t.title}</h2>

            <h3>"subtasks"</h3>
            <ul>
                {t.subtasks.iter().map(|s| UI! {
                    <li>{s}</li>
                })}
            </ul>

            {t.completed.then_some(UI! {
                <i><strong>"completed"</strong></i>
            })}
        </div>
    };

    println!("{}", uibeam::shoot(ui));
}

Beam - Component with Rust struct and JSX-like syntax

use uibeam::{Beam, UI};

struct Layout {
    title: String,
    children: UI,  // `children` field
}

impl Beam for Layout {
    fn render(self) -> UI {
        UI! {
            <html>
                <head>
                    <title>{self.title}</title>
                    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/tailwindcss@2.2.19/dist/tailwind.min.css">
                </head>
                <body class="bg-gray-100">
                    {self.children}
                </body>
            </html>
        }
    }
}

struct AdminPage {}

impl Beam for AdminPage {
    fn render(self) -> UI {
        UI! {
            <main class="container mx-auto flex-grow py-8 px-4">
                <section class="bg-white shadow-md rounded-lg p-6">
                    <h1 class="text-2xl font-bold text-gray-800 mb-6">
                        "Password"
                    </h1>
                    <form method="post" action="" class="w-full">
                        <div class="flex flex-col gap-4">
                            <div class="flex flex-col">
                                <label for="adminPassword" class="text-gray-700 text-sm font-bold mb-1">
                                    "password"
                                </label>
                                <input
                                    required
                                    type="password"
                                    id="adminPassword"
                                    name="adminPassword"
                                    class="py-2 px-3 border border-gray-400 rounded focus:outline-none focus:shadow-outline"
                                />
                            </div>
                        </div>
                        <div class="mt-6">
                            <button
                                type="submit"
                                class="bg-purple-500 hover:bg-purple-700 text-white py-2 px-4 rounded focus:outline-none focus:shadow-outline"
                            >
                                "Send"
                            </button>
                        </div>
                    </form>
                </section>
            </main>
        }
    }
}

fn main() {
    let ui = UI! {
        <Layout title="admin page">  // title: ("admin page").into()
            <AdminPage />  // children: (AdminPage {}).render()
        </Layout>
    };

    println!("{}", uibeam::shoot(ui));
}

Client Component - WASM islands

overview

#[client] makes Beam a WASM island : initially rendered on server, sent with serialized props, and hydrated with deserialized props on browser.

Signal, computed, effect, batch, untracked are available in them.

note

Currently UIBeam's client component system is built upon Preact. This may be rewritten in pure Rust in the future, but may not because of potential reduction in the final .wasm size.

usage

working example: examples/counter

  1. Activate "client" feature, and add serde to your dependencies:

    [dependencies]
uibeam = { version = "0.4" }
serde  = { version = "1", features = ["derive"] }

  2. Configure to export all your client components from a specific library crate. (e.g. lib.rs entrypoint, or another member crate of a workspace)

    (There's no problem if including ordinary Beams, not only client ones, in the lib crate.)

    Additionally, specify crate-type = ["cdylib", "rlib"] for the crate:

    [lib]
crate-type = ["cdylib", "rlib"]

  3. Define and use your client components:

    /* islands/src/lib.rs */

use uibeam::{UI, Beam};
use uibeam::{client, Signal, callback};
use serde::{Serialize, Deserialize};

// Client component located at **island boundary**
// must be `Serialize + for<'de> Deserialize<'de>`. (see NOTE below)
#[derive(Serialize, Deserialize)]
pub struct Counter;

// `#[client]` makes Beam a Wasm island.
// `(island)` means this beam is **island boundary**.
#[client(island)]
impl Beam for Counter {
    fn render(self) -> UI {
        let count = Signal::new(0);

        // `callback!` - a thin utility for callbacks over signals.
        let increment = callback!(
            // [dependent_signals, ...]
            [count],
            // closure depending on the signals
            |_| count.set(*count + 1)
        );
        /* << expanded >>

        let increment = {
            let count = count.clone();
            move |_| count.set(*count + 1)
        };
        
        */

        let decrement = callback!([count], |_| {
            count.set(*count - 1)
        });

        UI! {
            <p>"Count: "{*count}</p>
            <button onclick={increment}>"+"</button>
            <button onclick={decrement}>"-"</button>
        }
    }
}

    /* server/src/main.rs */

use islands::Counter;
use uibeam::UI;

async fn index() -> UI {
    UI! {
        <Counter />
    }
}

    NOTE: Client Beam at island boundary must be Serialize + for<'de> Deserialize<'de> for the Wasm island architecture. In contrast, #[client] components without (island), e.g. having children: UI or on_something: Box<dyn FnOnce(Event)> as props, can NOT implement Serialize nor Deserialize and can only be used internally in UI! of another client component. Especially note that client components at island boundary can't have children.

  4. Compile the lib crate into Wasm by wasm-pack build with RUSTFLAGS='--cfg hydrate' and --out-name hydrate --target web:

    # example when naming the lib crate `islands`

cd islands
RUSTFLAGS='--cfg hydrate' wasm-pack build --out-name 'hydrate' --target web

    # in a hot-reloading loop, `--dev` flag is recommended:

cd islands
RUSTFLAGS='--cfg hydrate' wasm-pack build --out-name 'hydrate' --target web --dev

    NOTE: Both hydrate cfg (not feature!) and hydrate out-name are required here. This restriction may be relaxted in future versions.

  5. Make sure that your server responds with a complete HTML consist of one <html></html> containing your page contents.

    Then, setup your server to serve the output directory (default: pkg) at /.uibeam route:

    /* axum example */

use axum::Router;
use tower_http::services::ServeDir;

fn app() -> Router {
    Router::new()
        .nest_service(
            "/.uibeam",
            ServeDir::new("./islands/pkg")
        )
        // ...
}

    (as a result, generated {crate name}/pkg/hydrate.js is served at /.uibeam/hydrate.js route, which is automatically loaded together with corresponding .wasm file in the hydration step on browser.)

Integrations with web frameworks

Enables UI to be returned directly as a HTML response.

Axum - by "axum" feature

axum = { version = "0.8" }
uibeam = { version = "0.4", features = ["axum"] }

use axum::{routing::get, Router};
use uibeam::UI;

async fn handler() -> UI {
    UI! {
        <h1>"Hello, Axum!"</h1>
    }
}

#[tokio::main]
async fn main() {
    let app = Router::new()
        .route("/", get(handler));

    let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();
    axum::serve(listener, app).await.unwrap();
}

Actix Web - by "actix-web" feature

actix-web = { version = "4.12" }
uibeam = { version = "0.4", features = ["actix-web"] }

use actix_web::{HttpServer, App, get};
use uibeam::UI;

#[get("/")]
async fn handler() -> UI {
    UI! {
        <h1>"Hello, Actix Web!"</h1>
    }
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
    HttpServer::new(||
        App::new()
            .service(handler)
    )
    .bind(("127.0.0.1", 8080))?
    .run()
    .await
}

Ohkami - by "ohkami" feature

  • UIBeam v0.3 is compatible with Ohkami v0.24.
  • Ohkami's openapi feature is supported via UIBeam's openapi feature flag.
  • UIBeam itself is runtime-agnostic and available with any async runtimes supported by Ohkami.
[dependencies]
tokio = { version = "1.48", features = ["full"] }
ohkami = { version = "0.24", features = ["rt_tokio"] }
uibeam = { version = "0.4", features = ["ohkami"] }
# when using ohkami's "openapi" feature,
# activate also uibeam's "openapi" feature.

use ohkami::{Ohkami, Route};
use uibeam::UI;

async fn handler() -> UI {
    UI! {
        <h1>"Hello, Ohkami!"</h1>
    }
}

#[tokio::main]
async fn main() {
    Ohkami::new((
        "/".GET(handler),
    ))
    .howl("localhost:5000")
    .await
}

License

UIBeam is licensed under MIT LICENSE.

Dependencies

~145–550KB
~13K SLoC