Axum Rails Cookie Extractor

Extract rails cookies in axum handlers.

Installation

As a dependency of a Rust project:

cargo add axum-rails-cookie

Library Usage

axum-rails-cookie is provided as a crate that you can use in your own code.

Cargo.toml:

[dependencies]
axum = "0.7.7"
tokio = {version = "1.41.0", features=["full"]}
anyhow = "1.0"
axum-macros = "0.4"
axum-rails-cookie = "0.1.0"

main.rs:

use axum::{routing::get, Extension, Router};
use axum_macros::debug_handler;
use axum_rails_cookie::{AppConfig, CookieAlgorithm, RailsCookie};

pub struct AppError(anyhow::Error);

impl axum::response::IntoResponse for AppError {
  fn into_response(self) -> axum::response::Response {
    (
      axum::http::StatusCode::INTERNAL_SERVER_ERROR,
      format!("Something went wrong: {}", self.0),
    )
      .into_response()
  }
}

impl<E> From<E> for AppError
where
  E: Into<anyhow::Error>,
{
  fn from(err: E) -> Self {
    Self(err.into())
  }
}

#[tokio::main]
async fn main() -> anyhow::Result<()> {
  let config = CookieConfig::new(
    "_my_app_session_id", 
    "3e3500446d813ba4be17b9322927e6cdd11fd502777641bffa9ee7b60b82ddeb8315f5fcb01f5399c42eb106d88015c67ccc7499715144eb2700a953daa320a5",
    CookieAlgorithm::AesHmac,
  );

  let app = Router::new()
    .route("/", get(root_handler))
    .layer(Extension(config));

  let listen_address = format!("{}:{}", "0.0.0.0", "8000");
  println!("Listening on {}", listen_address);

  let listener = tokio::net::TcpListener::bind(listen_address).await?;

  axum::serve(listener, app).await?;

  Ok(())
}

#[debug_handler]
async fn root_handler(rails_cookie: RailsCookie) -> Result<String, AppError> {
  if let RailsCookie::Ok(cookie) = rails_cookie {
    return Ok(cookie);
  }

  Ok("No cookie found".into())
}

Inpsiration

I wanted to be able to integrate axum based projects with existing rails applications and share session data between the two.

Security Notes

You should ensure that you never commit or track your secret key in your repository if you choose to use this code to encrypt/decrypt rails session cookies in your code. You could use git ignored configuration files or environment variables to store your secret key to ensure it is never committed.