Type Alias AsyncConnectionWrapper

pub type AsyncConnectionWrapper<C, B = Tokio> = AsyncConnectionWrapper<C, B>;

A helper type that wraps an AsyncConnection to provide a sync diesel::Connection implementation.

Internally this wrapper type will use block_on to wait for the execution of futures from the inner connection. This implies you cannot use functions of this type in a scope with an already existing tokio runtime. If you are in a situation where you want to use this connection wrapper in the scope of an existing tokio runtime (for example for running migrations via diesel_migration) you need to wrap the relevant code block into a tokio::task::spawn_blocking task.

Examples

use schema::users;
use diesel_async::async_connection_wrapper::AsyncConnectionWrapper;
use diesel::prelude::{RunQueryDsl, Connection};
let mut conn = AsyncConnectionWrapper::<DbConnection>::establish(&database_url)?;

let all_users = users::table.load::<(i32, String)>(&mut conn)?;

If you are in the scope of an existing tokio runtime you need to use tokio::task::spawn_blocking to encapsulate the blocking tasks

use schema::users;
use diesel_async::async_connection_wrapper::AsyncConnectionWrapper;

async fn some_async_fn() {
     // need to use `spawn_blocking` to execute
     // a blocking task in the scope of an existing runtime
     let res = tokio::task::spawn_blocking(move || {
         use diesel::prelude::{RunQueryDsl, Connection};
         let mut conn = AsyncConnectionWrapper::<DbConnection>::establish(&database_url)?;

         let all_users = users::table.load::<(i32, String)>(&mut conn)?;
         Ok::<_, Box<dyn std::error::Error + Send + Sync>>(())
     }).await;

}

Aliased Type

struct AsyncConnectionWrapper<C, B = Tokio> { /* private fields */ }