Crate diesel_async

Diesel-async provides async variants of diesel related query functionality

diesel-async is an extension to diesel itself. It is designed to be used together with the main diesel crate. It only provides async variants of core diesel traits, that perform actual io-work. This includes async counterparts the following traits:

• diesel::prelude::RunQueryDsl -> diesel_async::RunQueryDsl
• diesel::connection::Connection -> diesel_async::AsyncConnection
• diesel::query_dsl::UpdateAndFetchResults -> diesel_async::UpdateAndFetchResults

These traits closely mirror their diesel counter parts while providing async functionality.

In addition to these core traits 3 fully async connection implementations are provided by diesel-async:

• AsyncMysqlConnection (enabled by the mysql feature)
• AsyncPgConnection (enabled by the postgres feature)
• [SyncConnectionWrapper] (enabled by the sync-connection-wrapper/sqlite feature)

Ordinary usage of diesel-async assumes that you just replace the corresponding sync trait method calls and connections with their async counterparts.

use diesel::prelude::*;
use diesel_async::{RunQueryDsl, AsyncConnection};

diesel::table! {
   users(id) {
       id -> Integer,
       name -> Text,
   }
}

use crate::users::dsl::*;

let mut connection = AsyncPgConnection::establish(std::env::var("DATABASE_URL")?).await?;
let data = users
    // use ordinary diesel query dsl here
    .filter(id.gt(0))
    // execute the query via the provided
    // async variant of `diesel_async::RunQueryDsl`
    .load::<(i32, String)>(&mut connection)
    .await?;
let expected_data = vec![
    (1, String::from("Sean")),
    (2, String::from("Tess")),
];
assert_eq!(expected_data, data);

Re-exports

pub use scoped_futures;

Modules

async_connection_wrapperasync-connection-wrapper

This module contains an wrapper type that provides a diesel::Connection implementation for types that implement crate::AsyncConnection. Using this type might be useful for the following usecases:

methods

The traits used by QueryDsl.

pgpostgres

Provides types and functions related to working with PostgreSQL

pooled_connectionpool

This module contains support using diesel-async with various async rust connection pooling solutions

return_futures

The return types produced by the various RunQueryDsl methods

sync_connection_wrappersync-connection-wrapper

This module contains a wrapper type that provides a crate::AsyncConnection implementation for types that implement diesel::Connection. Using this type might be useful for the following usecases:

Structs

AnsiTransactionManager

An implementation of TransactionManager which can be used for backends which use ANSI standard syntax for savepoints such as SQLite and PostgreSQL.

AsyncMysqlConnectionmysql

A connection to a MySQL database. Connection URLs should be in the form mysql://[user[:password]@]host/database_name

AsyncPgConnectionpostgres

A connection to a PostgreSQL database.

Traits

AsyncConnection

An async connection to a database

RunQueryDsl

Methods used to execute queries.

SaveChangesDsl

Sugar for types which implement both AsChangeset and Identifiable

SimpleAsyncConnection

Perform simple operations on a backend.

TransactionManager

Manages the internal transaction state for a connection.

UpdateAndFetchResults

A trait defining how to update a record and fetch the updated entry on a certain backend.