mirror of
https://github.com/actix/actix-website
synced 2024-11-30 19:14:36 +01:00
48 lines
2.0 KiB
Markdown
48 lines
2.0 KiB
Markdown
---
|
|
title: Databases
|
|
menu: docs_patterns
|
|
weight: 1010
|
|
---
|
|
|
|
# Async Options
|
|
|
|
We have several example projects showing use of async database adapters:
|
|
|
|
- Postgres: https://github.com/actix/examples/tree/master/databases/postgres
|
|
- SQLite: https://github.com/actix/examples/tree/master/databases/sqlite
|
|
- MongoDB: https://github.com/actix/examples/tree/master/databases/mongodb
|
|
|
|
# Diesel
|
|
|
|
The current version of Diesel (v1) does not support asynchronous operations, so it is important to
|
|
use the [`web::block`][web-block] function to offload your database operations to the Actix runtime
|
|
thread-pool.
|
|
|
|
You can create action functions that correspond to all the operations your app will perform on the
|
|
database.
|
|
|
|
{{< include-example example="databases" file="main.rs" section="handler" >}}
|
|
|
|
Now you should set up the database pool using a crate such as `r2d2`, which makes many DB
|
|
connections available to your app. This means that multiple handlers can manipulate the DB at the
|
|
same time, and still accept new connections. Simply, the pool in your app state. (In this case, it's
|
|
beneficial not to use a state wrapper struct because the pool handles shared access for you.)
|
|
|
|
{{< include-example example="databases" file="main.rs" section="main" >}}
|
|
|
|
Now, in a request handler, use the `Data<T>` extractor to get the pool from app state and get a
|
|
connection from it. This provides an owned database connection that can be passed into a
|
|
[`web::block`][web-block] closure. Then just call the action function with the necessary arguments
|
|
and `.await` the result.
|
|
|
|
This example also maps the error to an `HttpResponse` before using the `?` operator but this is not
|
|
necessary if your return error type implements [`ResponseError`][response-error].
|
|
|
|
{{< include-example example="databases" file="main.rs" section="index" >}}
|
|
|
|
That's it! See the full example here:
|
|
https://github.com/actix/examples/tree/master/databases/diesel
|
|
|
|
[web-block]: https://docs.rs/actix-web/3/actix_web/web/fn.block.html
|
|
[response-error]: https://docs.rs/actix-web/3/actix_web/trait.ResponseError.html
|