Function leptos::create_blocking_resource

source · 
pub fn create_blocking_resource<S, T, Fu>(
    source: impl Fn() -> S + 'static,
    fetcher: impl Fn(S) -> Fu + 'static
) -> Resource<S, T>
where
    S: PartialEq + Clone + 'static,
    T: Serializable + 'static,
    Fu: Future<Output = T> + 'static,
Expand description

Creates a “blocking” Resource. When server-side rendering is used, this resource will cause any <Suspense/> you read it under to block the initial chunk of HTML from being sent to the client. This means that if you set things like HTTP headers or <head> metadata in that <Suspense/>, that header material will be included in the server’s original response.

This causes a slow time to first byte (TTFB) but is very useful for loading data that is essential to the first load. For example, a blog post page that needs to include the title of the blog post in the page’s initial HTML <title> tag for SEO reasons might use a blocking resource to load blog post metadata, which will prevent the page from returning until that data has loaded.

Note: This is not “blocking” in the sense that it blocks the current thread. Rather, it is blocking in the sense that it blocks the server from sending a response.

When used with the leptos_router and SsrMode::PartiallyBlocked, a blocking resource will ensure <Suspense/> blocks depending on the resource are fully rendered on the server side, without requiring JavaScript or WebAssembly on the client.