Example with connection state AND JSON payload

[nsallis]

Summary

We have several examples of passing connections/pools via state (I love this feature!). However, there doesn't seem to be an example of a handler that takes both a connection from state AND a JSON payload. Initial attempts to do this seem to make our functions no longer qualified as handlers. I wonder if there's a nice way of doing this without having to write implementations for every combination of payload and connection. If someone can guide me I would be happy to update the examples for this. I'm specifically looking at the sqlx example

axum/examples/sqlx-postgres/src/main.rs

Line 65 in dd8d4a4

State(pool): State<PgPool>,

.

axum version

0.8.4

[mladedav]

What did you try and how did it fail?

[nsallis]

I followed the AppSate as it is in the examples (AppState just holds my pool):
pub async fn create_entity(State(state): State<AppState>, Json(payload): Json<SharedTypes::CreateEntity> ) -> (StatusCode, String) {

However, when I attempt to add this to a router (ideally with .nest since it's in a separate file that should define its own routes) I keep getting error messages about the trait bound for<'a> Router: tower_service::Service<IncomingStream<'a, tokio::net::TcpListener>> is not satisfied. I don't see any implementations for the router in the examples that fixes this, so I'm assuming this is something I'm doing wrong, but the error message is not helpful at all.

[nsallis]

Ideally I would have a separate "service" file with a getRoutes function that would return a router. Then in main, I would .nest those routes. However, as soon as I add AppState to my handlers that fails with the above error.

[mladedav]

What you did should work. Can you post the relevant code and error messages?

[nsallis]

Ahh something that was not clear to me (maybe should have been): with_state needs to specifically be on the routes/nests that take that state. I had falsely assumed that just applied to the entire app/router and the error message wasn't super clear as a new-comer.

[mladedav]

It does apply to the whole router, but you need to call it after the routes, not before. Specifically Router<AppState> needs AppState, it does not provide the given state.