How to define a static variable and use it elsewhere?"

[callmeitachi]

Hi, I've been trying to build a website using Rust's Leptos framework with SurrealDB, but I've encountered an issue. I defined a global DB variable but can't use it elsewhere. How can I solve this problem? Here's how I defined my DB variable：

              #[tokio::main]
              async fn main() {
                  use axum::Router;
                  use leptos::logging::log;
                  use leptos::prelude::*;
                  use leptos_axum::{generate_route_list, LeptosRoutes};
                  use bs_web::app::*;

-                   use std::sync::LazyLock;
-                   use surrealdb::{Surreal,engine::remote::ws::{Client,Ws},opt::auth::Root};
-                   static DB:LazyLock<Surreal<Client>>=LazyLock::new(Surreal::init);
-                   DB.connect::<Ws>("localhost:8000").await.unwrap();
-                   DB.signin(Root {
-                       username:"root",
-                       password:"root",
-                   })
-                   .await.unwrap();
-                   DB.use_ns("test").use_db("test").await.unwrap();

                  .........................
                 }

[gbj]

I defined a global DB variable

No, you defined a static but it is not global: it is scoped to the main function, because that is where you defined it, just like any other variable. If you want it to be global you need to defined it in a global scope, above the main function, and make it pub so it can be imported elsewhere. There is nothing Leptos-specific here; you can consult general Rust language resources for further help.

[callmeitachi]

Oh, thanks, this issue has been resolved. But when I execute cargo leptos build, the surrealdb crate reports an error. I'm not sure where it went wrong. Here's how I imported this crate:

        surrealdb= { version = "2.3.7", optional = true }
        ssr = [
            "dep:axum",
            "dep:tokio",
            "dep:leptos_axum",
            "dep:surrealdb",
            "dep:dotenv",
            "leptos/ssr",
            "leptos_meta/ssr",
            "leptos_router/ssr",
        ]~~~
failed to resolve: use of unresolved module or unlinked crate `surrealdb`
 --> src\pages\register.rs:4:5
  |
4 | use surrealdb::opt::auth::Record;
  |     ^^^^^^^^^ use of unresolved module or unlinked crate `surrealdb`

[gbj]

Right, because you're probably now defining a global that uses surrealdb (only available on ssr) but defining that global in a place that is compiled for both client and server.

Try

#[cfg(feature = "ssr)]
static DB: LazyLock /* etc */;

[callmeitachi]

Oh, it's perfectly resolved now. Guess I still need to brush up on Rust.