🥠 Sessions as a `tower` and `axum` middleware.

This crate provides sessions, key-value pairs associated with a site visitor, as a tower middleware.

It offers:

• Pluggable Storage Backends: Bring your own backend simply by implementing the SessionStore trait, fully decoupling sessions from their storage.
• Minimal Overhead: Sessions are only loaded from their backing stores when they're actually used and only in e.g. the handler they're used in. That means this middleware can be installed anywhere in your route graph with minimal overhead.
• An axum Extractor for Session: Applications built with axum can use Session as an extractor directly in their handlers. This makes using sessions as easy as including Session in your handler.
• Simple Key-Value Interface: Sessions offer a key-value interface that supports native Rust types. So long as these types are Serialize and can be converted to JSON, it's straightforward to insert, get, and remove any value.
• Strongly-Typed Sessions: Strong typing guarantees are easy to layer on top of this foundational key-value interface.

This crate's session implementation is inspired by the Django sessions middleware and it provides a transliteration of those semantics.

Session data persistence is managed by user-provided types that implement SessionStore. What this means is that applications can and should implement session stores to fit their specific needs.

That said, a number of session store implmentations already exist and may be useful starting points.

Have a store to add? Please open a PR adding it.

To facilitate authentication and authorization, we've built axum-login on top of this crate. Please check it out if you're looking for a generalized auth solution.

To use the crate in your project, add the following to your Cargo.toml file:

[dependencies]
tower-sessions = "0.12.2"

use std::net::SocketAddr;

use axum::{response::IntoResponse, routing::get, Router};
use serde::{Deserialize, Serialize};
use time::Duration;
use tower_sessions::{Expiry, MemoryStore, Session, SessionManagerLayer};

const COUNTER_KEY: &str = "counter";

#[derive(Default, Deserialize, Serialize)]
struct Counter(usize);

async fn handler(session: Session) -> impl IntoResponse {
    let counter: Counter = session.get(COUNTER_KEY).await.unwrap().unwrap_or_default();
    session.insert(COUNTER_KEY, counter.0 + 1).await.unwrap();
    format!("Current count: {}", counter.0)
}

#[tokio::main]
async fn main() {
    let session_store = MemoryStore::default();
    let session_layer = SessionManagerLayer::new(session_store)
        .with_secure(false)
        .with_expiry(Expiry::OnInactivity(Duration::seconds(10)));

    let app = Router::new().route("/", get(handler)).layer(session_layer);

    let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
    let listener = tokio::net::TcpListener::bind(&addr).await.unwrap();
    axum::serve(listener, app.into_make_service())
        .await
        .unwrap();
}

You can find this example as well as other example projects in the example directory.

This crate uses #![forbid(unsafe_code)] to ensure everything is implemented in 100% safe Rust.

We've put together a number of examples to help get you started. You're also welcome to open a discussion and ask additional questions you might have.

We appreciate all kinds of contributions, thank you!