Function axum::routing::nest

pub fn nest<S, B>(description: &str, svc: S) -> Nested<S, EmptyRouter<S::Error>> where
    S: Service<Request<B>> + Clone, 

Nest a group of routes (or a Service) at some path.

This allows you to break your application into smaller pieces and compose them together. This will strip the matching prefix from the URL so the nested route will only see the part of URL:

use axum::{routing::nest, prelude::*};
use http::Uri;

async fn users_get(uri: Uri) {
    // `users_get` doesn't see the whole URL. `nest` will strip the matching
    // `/api` prefix.
    assert_eq!(uri.path(), "/users");
}

async fn users_post() {}

async fn careers() {}

let users_api = route("/users", get(users_get).post(users_post));

let app = nest("/api", users_api).route("/careers", get(careers));

Take care when using nest together with dynamic routes as nesting also captures from the outer routes:

use axum::{routing::nest, prelude::*};

async fn users_get(params: extract::UrlParamsMap) {
    // Both `version` and `id` were captured even though `users_api` only
    // explicitly captures `id`.
    let version = params.get("version");
    let id = params.get("id");
}

let users_api = route("/users/:id", get(users_get));

let app = nest("/:version/api", users_api);

nest also accepts any Service. This can for example be used with tower_http::services::ServeDir to serve static files from a directory:

use axum::{
    routing::nest, service::{get, ServiceExt}, prelude::*,
};
use tower_http::services::ServeDir;

// Serves files inside the `public` directory at `GET /public/*`
let serve_dir_service = ServeDir::new("public");

let app = nest("/public", get(serve_dir_service));

If necessary you can use RoutingDsl::boxed to box a group of routes making the type easier to name. This is sometimes useful when working with nest.