Leptos Query

About

Leptos Query is a robust asynchronous state management library for Leptos, providing simplified data fetching, integrated reactivity, server-side rendering support, and intelligent cache management.

Heavily inspired by Tanstack Query.

Read the introduction article here: The Forging of Leptos Query

Why Choose Leptos Query?

Leptos Query focuses on simplifying your data fetching process and keeping your application's state effortlessly synchronized and up-to-date. Here's how it's done:

Key Features

Configurable Caching & SWR: Queries are cached by default, ensuring quick access to your data. You can configure your stale and cache times per query with Stale While Revalidate (SWR) system.
Reactivity at the Core: Leptos Query deeply integrates with Leptos' reactive system to transform asynchronous query fetchers into reactive Signals.
Server-Side Rendering (SSR) Compatibility: Fetch your queries on the server and smoothly serialize them to the client, just as you would with a Leptos Resource.
Efficient De-duplication: No unnecessary fetches here! If you make multiple queries with the same Key, Leptos Query smartly fetches only once.
Manual Invalidation: Control when your queries should be invalidated and refetched for that ultimate flexibility.
Scheduled Refetching: Set up your queries to refetch on a customized schedule, keeping your data fresh as per your needs.
Manual Query Data Mutations: Useful when you have updated a value and you want to manually set it in cache instead of waiting for query to refetch.

Installation

cargo add leptos_query

Then add the relevant feature(s) to your Cargo.toml

[features]
hydrate = [
    "leptos_query/hydrate",
    # ...
]
ssr = [
    "leptos_query/ssr",
    # ...
 ]

Quick Start

If you are using SSR you may have to use supress_query_load in your server's main function. See the FAQ for more information.

In the root of your App, provide a query client:

use leptos_query::*;
use leptos::*;

#[component]
pub fn App() -> impl IntoView {
    // Provides Query Client for entire app.
    provide_query_client();

    // Rest of App...
}

Then make a query function.

 use leptos::*;
 use leptos_query::*;
 use std::time::Duration;
 use serde::*;

 // Data type.
 #[derive(Clone, Deserialize, Serialize)]
 struct Monkey {
     name: String,
 }


 // Monkey fetcher.
 async fn get_monkey(id: String) -> Monkey {
    todo!()
 }

 // Query for a Monkey.
 fn use_monkey_query(id: impl Fn() -> String + 'static) -> QueryResult<Monkey, impl RefetchFn> {
     leptos_query::use_query(
         id,
         get_monkey,
         QueryOptions {
             default_value: None,
             refetch_interval: None,
             resource_option: ResourceOption::NonBlocking,
             // Considered stale after 10 seconds.
             stale_time: Some(Duration::from_secs(10)),
             // Infinite cache time.
             cache_time: None,
         },
     )
 }

Now you can use the query in any component in your app.

#[component]
fn MonkeyView(id: String) -> impl IntoView {
    let QueryResult {
        data,
        is_loading,
        is_fetching,
        is_stale
        ..
    } = use_monkey_query(move || id.clone());

    view! {
      // You can use the query result data here.
      // Everything is reactive.
       <div>
           <div>
               <span>"Loading Status: "</span>
               <span>{move || { if is_loading.get() { "Loading..." } else { "Loaded" } }}</span>
           </div>
           <div>
               <span>"Fetching Status: "</span>
               <span>
                   {move || { if is_fetching.get() { "Fetching..." } else { "Idle" } }}
               </span>
           </div>
           <div>
               <span>"Stale Status: "</span>
               <span>
                   {move || { if is_stale.get() { "Stale" } else { "Fresh" } }}
               </span>
           </div>
           // Query data should be read inside a Transition/Suspense component.
           <Transition
               fallback=move || {
                   view! { <h2>"Loading..."</h2> }
               }>
               {move || {
                   data.get()
                       .map(|monkey| {
                           view! { <h2>{monkey.name}</h2> }
                       })
               }}
           </Transition>
       </div>
    }
}