How to provide single query string param without HashMap<_,_>?

[Kimishu]

Summary

I need to provide a uuid variable to my /test route. And also I noticed that the only available way is to creating a HashMap with params (like <String, String>) and then in handler function get them and check, does them fits or no.

#[tokio::main]
async fn main() {
    let router = axum::Router::new()
    .route("/test", get(test));

    let listener = tokio::net::TcpListener::bind("0.0.0.0:8000").await.unwrap();
    axum::serve(listener, router).await.unwrap()
}

pub async fn test(
    Query(id): Query<Uuid>
) -> impl IntoResponse {
    println!("query value is: {}", id)
}

Error: Failed to deserialize query string: invalid type: map, expected a UUID string
Will there be an easier option for this in the future?

axum version

0.8.1

[Turbo87]

query parameters are essentially key-value pairs. how would you expect Query<Uuid> to work since it only specifies a single data type for the value, but not the key that it corresponds to?

[Kimishu]

It's a bit tricky to explain, but it can be done more obviously.
Like, we can check handler params and create a concrete route with n params, all other cases will be ignored and returned 404.

[Turbo87]

I'm still not sure what kind of URL you expect to work with this route definition. since it seems like a somewhat exotic use case it might be easier to write a custom extractor instead.

[Kimishu]

Yep, i'll try to create custom extractor later.

UPD: By the way, I expected something like that:

async fn test_handler(
    first_param: Query<Option<u64>>,
    second_param: Query<Option<u64>>
) -> impl IntoResponse { ... }

[jplatte]

If your entire query string is just a UUID, you can use RawQuery and parse it inside your handler function, or make your own extractor.

If you want to parse id=<uuid>, create a struct like

#[derive(Deserialize)]
struct TestParams {
    id: Uuid,
}

and use Query<TestParams>.

[Kimishu]

RawQuery fits for me, thanks, I'll try it!