mismatched types and web:Data<> problem when called from different file

[Leanerz]

Hi all,

I have rust folder like so:

main.rs
api/
- user_api/
-- mod.rs
-- routes.rs
-- user_api.rs

mod.rs:

mod routes;
mod user_api;

pub use routes::init_routes;
pub use user_api::{AddUsers, testOnly};

This function is inside: user_api.rs file:

    pub async fn AddUsers(cgrpc: APIClient<tonic::transport::Channel>, uid: u64) -> Result<TResponse<UserResponse>, Status> {
            let request = tonic::Request::new(UserUID {
                   uid
            });
        

            let response = cgrpc.clone().nuser(request).await;

            println!("RESPONSE={:?}", response);

            response
    }

This one inside routes.rs:

#[post("/adduser")]
async fn add_user(_req: HttpRequest, cgrpc: web::Data<APIClient<tonic::transport::Channel>>) -> HttpResponse {

    user_api::testOnly(1);

    match AddUsers(cgrpc, 1) {
        Ok(result) => HttpResponse::Ok().json(result.unwrap()),
        Err(err) => HttpResponse::Ok().json(err),
    }
}

But I get this error for cgrpc:

mismatched types

expected struct `api::user_api::user_api::client_grpc_api::gateway_client::APIClient`, found struct `actix_web::web::Data`

note: expected struct `api::user_api::user_api::client_grpc_api::gateway_client::APIClient<tonic::transport::Channel>`
         found struct `actix_web::web::Data<api::user_api::routes::client_grpc_api::gateway_client::APIClient<tonic::transport::Channel>>`rustc(E0308)

Inside main.rs:

    ...
    HttpServer::new(move || {
        App::new()
            .data(cgrpc.clone())
            .wrap(middleware::Compress::new(ContentEncoding::Br))
            .wrap(middleware::Logger::default())
            .service(web::scope("/user").configure(api::user_api::init_routes))
    })
    .bind("127.0.0.1:80")?
    .run()
    .await

I can copy paste all functions inside user_api.rs to routes.rs and use directly:

web::Data<APIClient<tonic::transport::Channel>>

But for organization purpose, I need it like so, your help will be appreciated.

Thank you !

[aliemjay]

In add_user, cgrpc is of type Data. You can only get &APIClient<_> from it by either using Data::get_ref or by Deref trait and deref coercion. However, you should modify AddUsers to receive a &APIClient, instead of APIClient (or you can clone it!).

Here is an example.

Modify AddUsers:

pub async fn AddUsers(cgrpc: &APIClient<tonic::transport::Channel> ...

in add_user (you also need to await):

AddUsers(cgrpc.get_ref(), 1).await;
//  or by deref coercion
AddUsers(&cgrpc, 1).await;

[Leanerz]

It compile without a problem when it is before HttpServer::new(move || {, but if it is preferable to put it inside I will do that.

Wondering what is the difference.

🙏 🙏 🙏

[robjtede]

Wondering what is the difference.

https://actix.rs/actix-web/actix_web/struct.App.html#shared-mutable-state

[Leanerz]

Wondering what is the difference.

https://actix.rs/actix-web/actix_web/struct.App.html#shared-mutable-state

In the example you shared it looks like as I've always did, but was curious to know what is the difference if I put the build of grpc client inside HttpServer::new(move || {.

Just by guess, I think in the second case, I don't have to clone the client like in the official example since it's inside and he execute it for each new request (Which is same at the end).

Thank you for giving me the opportunity to learn more about it.

I appreciate it :)

[robjtede]

Put simply:
Created with Arc/Data outside HttpServer: 1 instance
Created inside HttpServer with N workers: N instances

[Leanerz]

Put simply:
Created with Arc/Data outside HttpServer: 1 instance
Created inside HttpServer with N workers: N instances

Got it now ! Thank you !