Extension middleware not added to fallbacks?

[Pranoy1c]

I have the following simple code:

use std::{net::SocketAddr, path::Path};

use axum::{extract::{ConnectInfo, Request, State}, middleware::Next, response::{Html, IntoResponse, Response}, routing::{get, get_service}, Extension};
use tower_http::services::ServeDir;

#[derive(Clone, Debug)]
struct AppState {
    something: String
}

#[tokio::main]
async fn main() {

    let state = AppState {
        something: "Hello world!".to_string()
    };

    let app = axum::Router::new()
        .route("/", get(home_get))
        .nest_service("/assets", get_service(ServeDir::new(Path::new("assets"))))
        .fallback(get(home_get).with_state(state.clone()))
        .route_layer(axum::middleware::from_fn_with_state(state.clone(),info_middleware))
        .with_state(state);

    let listener = tokio::net::TcpListener::bind(":::7070").await.unwrap();
    axum::serve(listener, app.into_make_service_with_connect_info::<SocketAddr>()).await.unwrap();
}

async fn home_get(state: State<AppState>, connection_info: Extension<MyConnectionInfo>) -> Response {
    Html(format!("{} You called from: {}",state.something,connection_info.ip)).into_response()
}

#[derive(Clone, Debug)]
pub struct MyConnectionInfo {
    pub ip: String
}

pub async fn info_middleware(addr: ConnectInfo<SocketAddr>, mut request: Request, next: Next) -> Response {
    request.extensions_mut().insert(MyConnectionInfo {ip: addr.to_string()});
    next.run(request).await
}

In a real world example, my state would contain the database pool from sqlx and the info_middleware would do things like ensure token is valid, extract IP address, User agent etc. and make it available to all handlers.

For routing, basically:

1. "/" is to take user to home_get
2. "/assets/favicon.ico" serves the favicon file in the assets folder, and
3. any other routes is to fallback to home_get.

1 and 2 work well. 3 does not.

For example, "/submit" fails with below 500 Internal error:

Missing request extension: Extension of type `fallbackdemo::MyConnectionInfo` was not found. Perhaps you forgot to add it? See `axum::Extension`.

I think this is because the Extension middleware isn't accessible to fallbacks?

How to make it work? Or some workaround (other than having to specify every single fallback route manually)?

[jplatte]

Your using route_layer, which registers a middleware that only runs when an explicit route is matched. Use layer if you want the middleware to also apply to the fallback.

Also, your with_state call on the fallback MethodRouter seems like a no-op, without it the later with_state call would apply to it and do the same thing.