Crate servable

Crate servable 

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§Servable: a simple web framework

CI Cargo API reference

A minimal, convenient web micro-framework built around htmx, Axum, and Maud.
This powers my homepage. See example usage here.

§Features

servable provides abstractions that implement common utilities needed by an http server.

  • response headers and cache-busting utilities
  • client device detection (mobile / desktop)
  • server-side image optimization (see the image feature below)
  • ergonomic htmx integration (see htmx-* features below)

§Quick Start

ⓘ
use servable::{ServableRouter, servable::StaticAsset, mime::MimeType};

#[tokio::main]
async fn main() {
	let route = ServableRouter::new()
		.add_page(
			"/hello",
			StaticAsset {
				bytes: b"Hello, World!",
				mime: MimeType::Text,
			},
		);

	// usual axum startup routine
	let app = route.into_router();
	let listener = tokio::net::TcpListener::bind("0.0.0.0:3000")
		.await
		.unwrap();

	axum::serve(listener, app).await.unwrap();
}

§Core Concepts

§The Servable trait

The Servable trait is the foundation of this stack.
servable provides implementations for a few common servables:

  • StaticAsset, for static files like CSS, JavaScript, images, or plain bytes:

    use servable::{StaticAsset, mime::MimeType};

let asset = StaticAsset {
	bytes: b"body { color: red; }",
	mime: MimeType::Css,
	ttl: StaticAsset::DEFAULT_TTL
};

  • Redirect, for simple http redirects:

    use servable::Redirect;

let redirect = Redirect::new("/new-location").unwrap();

  • HtmlPage, for dynamically-rendered HTML pages

    use servable::{HtmlPage, PageMetadata};
use maud::html;
use std::pin::Pin;

let page = HtmlPage::default()
	.with_meta(PageMetadata {
		title: "My Page".into(),
		description: Some("A great page".into()),
		..Default::default()
	})
	.with_render(|_page, ctx| {
		Box::pin(async move {
			html! {
				h1 { "Welcome!" }
				p { "Route: " (ctx.route) }
			}
		})
	});

    HtmlPage automatically generates a <head> and wraps its rendered html in <html><body>.

§ServableRouter

A ServableRouter exposes a collection of Servables under different routes. It implements tower’s Service trait, and can be easily be converted into an Axum Router. Construct one as follows:

let route = ServableRouter::new()
	.add_page("/", home_page)
	.add_page("/about", about_page)
	.add_page("/style.css", stylesheet)
	.with_404(custom_404_page); // override default 404

§Features

  • image: enable image transformation via query parameters. This makes tokio a dependency.
    When this is enabled, all StaticAssets with a valid mimetype can take an optional t= query parameter.
    See the TransformerEnum in this crate’s documentation for details.

    When image is enabled, the image below…

    let route = ServableRouter::new()
	.add_page(
		"/image.png",
		StaticAsset {
			bytes: b"fake image data",
			mime: MimeType::Png,
			ttl: StaticAsset::DEFAULT_TTL
		}
	);

    …may be accessed as follows:

    # Original image
GET /image.png

# Resize to max 800px on longest side
GET /image.png?t=maxdim(800,800)

# Crop to a 400x400 square at the center of the image
GET /image.png?t=crop(400,400,c)

# Chain transformations and transcode
GET /image.png?t=maxdim(800,800);crop(400,400);format(webp)

  • htmx-2.0.8: Include htmx sources in the compiled executable.
    Use as follows:

    let route = ServableRouter::new()
	.add_page("/htmx.js", servable::HTMX_2_0_8)
	.add_page("/htmx-json-enc.js", servable::EXT_JSON_1_19_12);

§Caching and cache-busting

Control caching behavior per servable:

use chrono::TimeDelta;
use servable::HtmlPage;

let page = HtmlPage::default()
	.with_ttl(Some(TimeDelta::hours(1)))
	.with_private(false);

Headers are automatically generated:

  • Cache-Control: public, max-age=3600 (default)
  • Cache-Control: private, max-age=31536000 (if private is true)

We also provide a static CACHE_BUST_STR, which may be formatted into urls to force cache refresh whenever the server is restarted:

use chrono::TimeDelta;
use servable::{HtmlPage, CACHE_BUST_STR, ServableWithRoute, StaticAsset, ServableRouter};
use servable::mime::MimeType;

pub static HTMX: ServableWithRoute<StaticAsset> = ServableWithRoute::new(
	|| format!("/{}/main.css", *CACHE_BUST_STR),
	StaticAsset {
		bytes: "div{}".as_bytes(),
		mime: MimeType::Css,
		ttl: StaticAsset::DEFAULT_TTL,
	},
);


let route = HTMX.route();
println!("Css is at {route}");

let router = ServableRouter::new()
	.add_page_with_route(&HTMX);

§TODO:

  • cache-busting fonts in css is not possible, we need to dynamic replace urls

Modules§

mime
Strongly-typed MIME types via MimeType.

Structs§

ClientInfo
Inferred information about the client that requested a certain route.
HtmlPage
A complete, dynamically-rendered blob of HTML.
PageMetadata
Redirect
A simple http edirect
RenderContext
Additional context available to crate::servable::Servables when generating their content
Rendered
An asset to return from an http route
ServableRouter
A set of related Servables under one route.
ServableWithRoute
A Servable and the route it is available at
StaticAsset
A static blob of bytes

Enums§

DeviceType
The type of device that requested a page
RedirectCode
RenderedBody
The contents of a response produced by a crate::servable::Servable
ScriptSource

Statics§

CACHE_BUST_STR
A unique string that can be used for cache-busting.

Traits§

RenderedBodyType
A utility trait, used to control the kind of body Rendered contains.
Servable
Something that may be served over http. If implementing this trait, refer to sample implementations in redirect::Redirect, asset::StaticAsset and html::HtmlPage.