Crate leptos_router

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Leptos Router

Leptos Router is a router and state management tool for web applications written in Rust using the Leptos web framework. It is ”isomorphic,” i.e., it can be used for client-side applications/single-page apps (SPAs), server-side rendering/multi-page apps (MPAs), or to synchronize state between the two.

Note: This is a work in progress. The feature to pass client-side route State in History.state, in particular, is incomplete.

Philosophy

Leptos Router is built on a few simple principles:

  1. URL drives state. For web applications, the URL should be the ultimate source of truth for most of your app’s state. (It’s called a Universal Resource Locator for a reason!)

  2. Nested routing. A URL can match multiple routes that exist in a nested tree and are rendered by different components. This means you can navigate between siblings in this tree without re-rendering or triggering any change in the parent routes.

  3. Route-based data loading. Each route should know exactly which data it needs to render itself when the route is defined. This allows each route’s data to be reloaded independently, and allows data from nested routes to be loaded in parallel, avoiding waterfalls.

  4. Progressive enhancement. The A and Form components resolve any relative nested routes, render actual <a> and <form> elements, and (when possible) upgrading them to handle those navigations with client-side routing. If you’re using them with server-side rendering (with or without hydration), they just work, whether JS/WASM have loaded or not.

Example


use leptos::*;
use leptos_router::*;

#[component]
pub fn RouterExample(cx: Scope) -> impl IntoView {
  view! {
    cx,
    <div id="root">
      // we wrap the whole app in a <Router/> to allow client-side navigation
      // from our nav links below
      <Router>
        // <nav> and <main> will show on every route
        <nav>
          // LR will enhance the active <a> link with the [aria-current] attribute
          // we can use this for styling them with CSS like `[aria-current] { font-weight: bold; }`
          <A href="contacts">"Contacts"</A>
          <A href="about">"About"</A>
          <A href="settings">"Settings"</A>
        </nav>
        <main>
          // <Routes/> both defines our routes and shows them on the page
          <Routes>
            // our root route: the contact list is always shown
            <Route
              path=""
              view=move |cx| view! { cx,  <ContactList/> }
            >
              // users like /gbj or /bob
              <Route
                path=":id"
                view=move |cx| view! { cx,  <Contact/> }
              />
              // a fallback if the /:id segment is missing from the URL
              <Route
                path=""
                view=move |_| view! { cx,  <p class="contact">"Select a contact."</p> }
              />
            </Route>
            // LR will automatically use this for /about, not the /:id match above
            <Route
              path="about"
              view=move |cx| view! { cx,  <About/> }
            />
          </Routes>
        </main>
      </Router>
    </div>
  }
}

type ContactSummary = (); // TODO!
type Contact = (); // TODO!()

// contact_data reruns whenever the :id param changes
async fn contact_data(id: String) -> Contact {
  todo!()
}

// contact_list_data *doesn't* rerun when the :id changes,
// because that param is nested lower than the <ContactList/> route
async fn contact_list_data() -> Vec<ContactSummary> {
  todo!()
}

#[component]
fn ContactList(cx: Scope) -> impl IntoView {
  // loads the contact list data once; doesn't reload when nested routes change
  let contacts = create_resource(cx, || (), |_| contact_list_data());
  view! {
    cx,
    <div>
      // show the contacts
      <ul>
        {move || contacts.read().map(|contacts| view! { cx, <li>"todo contact info"</li> } )}
      </ul>

      // insert the nested child route here
      <Outlet/>
    </div>
  }
}

#[component]
fn Contact(cx: Scope) -> impl IntoView {
  let params = use_params_map(cx);
  let data = create_resource(
    cx,
    move || params.with(|p| p.get("id").cloned().unwrap_or_default()),
    move |id| contact_data(id)
  );
  todo!()
}

#[component]
fn About(cx: Scope) -> impl IntoView {
  todo!()
}

Module Route Definitions

Routes can also be modularized and nested by defining them in separate components, which can be located in and imported from other modules. Components that return <Route/> should be marked #[component(transparent)], as in this example:

use leptos::*;
use leptos_router::*;

#[component]
pub fn App(cx: Scope) -> impl IntoView {
  view! { cx,
    <Router>
      <Routes>
        <Route path="/" view=move |cx| {
          view! { cx, "-> /" }
        }/>
        <ExternallyDefinedRoute/>
      </Routes>
    </Router>
  }
}

// `transparent` here marks the component as returning data (a RouteDefinition), not a view
#[component(transparent)]
pub fn ExternallyDefinedRoute(cx: Scope) -> impl IntoView {
  view! { cx,
    <Route path="/some-area" view=move |cx| {
      view! { cx, <div>
        <h2>"Some Area"</h2>
        <Outlet/>
      </div> }
    }>
      <Route path="/path-a/:id" view=move |cx| {
        view! { cx, <p>"Path A"</p> }
      }/>
      <Route path="/path-b/:id" view=move |cx| {
        view! { cx, <p>"Path B"</p> }
      }/>
    </Route>
  }
}

Feature Flags

  • csr Client-side rendering: Generate DOM nodes in the browser
  • ssr Server-side rendering: Generate an HTML string (typically on the server)
  • hydrate Hydration: use this to add interactivity to an SSRed Leptos app
  • stable By default, Leptos requires nightly Rust, which is what allows the ergonomics of calling signals as functions. Enable this feature to support stable Rust.

Important Note: You must enable one of csr, hydrate, or ssr to tell Leptos which mode your app is operating in.

Re-exports

pub use matching::*;

Macros

A declarative way of creating a ParamsMap.

Structs

Props for the [A] component.
Builder for AProps instances.
Props for the ActionForm component.
The default integration when you are running in the browser, which uses the History API.
Props for the [Form] component.
Builder for FormProps instances.
A reactive description of the current URL, containing equivalents to the local parts of the browser’s Location.
A description of a navigation.
Props for the MultiActionForm component.
Options that can be used to configure a navigation. Used with use_navigate.
Props for the Outlet component.
Builder for OutletProps instances.
A key-value map of the current named route params and their values.
Context to contain all possible routes.
Context type that contains information about the current, matched route.
Props for the Route component.
Builder for RouteProps instances.
Context type that contains information about the current router state.
The wrapper type that the Router uses to interact with a History. This is automatically provided in the browser. For the server, it should be provided as a context.
Props for the Router component.
Builder for RouterProps instances.
Props for the Routes component.
Builder for RoutesProps instances.
A generic router integration for the server side. All its need is the current path.

Enums

An error that occurs during navigation.
Errors that can occur while parsing params using Params.

Traits

The Router relies on a RouterIntegrationContext, which tells the router how to find things like the current URL, and how to navigate to a new page. The History trait can be implemented on any type to provide this information.
A simple method of deserializing key-value data (like route params or URL search) into a concrete data type. Self should typically be a struct in which each field’s type implements FromStr.
Describes a value that is either a static or a reactive URL, i.e., a String, a &str, or a reactive Fn() -> String.

Functions

An HTML a progressively enhanced to use client-side routing.
Automatically turns a server Action into an HTML form progressively enhanced to use client-side routing.
An HTML form progressively enhanced to use client-side routing.
Automatically turns a server MultiAction into an HTML form progressively enhanced to use client-side routing.
Displays the child route nested in a parent route, allowing you to control exactly where that child route is displayed. Renders nothing if there is no nested child.
Describes a portion of the nested layout of the app, specifying the route it should match, the element it should display, and data that should be loaded alongside the route.
Provides for client-side and server-side routing. This should usually be somewhere near the root of the application.
Contains route definitions and manages the actual routing process.
Creates a reactive location from the given path and state.
Generates a list of all routes this application could possibly serve. This returns the raw routes in the leptos_router format. Odds are you want generate_route_list() from either the actix or axum integrations if you want to work with their router
Returns the current Location, which contains reactive variables
Returns a function that can be used to navigate to a new route.
Returns the current route params, parsed into the given type, or an error.
Returns a raw key-value map of route params.
Returns the current URL search query, parsed into the given type, or an error.
Returns a raw key-value map of the URL search query.
Resolves the given path relative to the current route.
Returns the current RouteContext, containing information about the matched route.
Returns the current RouterContext, containing information about the router’s state.