Cookies

rustdocs

The trillium-cookies crate parses inbound Cookie request headers and accumulates outbound Set-Cookie response headers. It provides a CookiesHandler that must be placed in the handler chain before any handler that reads or writes cookies, and a CookiesConnExt trait that extends Conn with cookie access methods.

Setup

use trillium_cookies::{CookiesConnExt, CookiesHandler};

fn main() {
    trillium_smol::run((
        CookiesHandler::new(),
        |conn: trillium::Conn| async move {
            // cookies are now available
            conn.ok("handled")
        },
    ));
}

❗ CookiesHandler must come before any handler that calls conn.cookies() or conn.with_cookie(). If the session handler is also in use, it must come after CookiesHandler.

Reading cookies

conn.cookies() returns a reference to the CookieJar for the current request:

use trillium_cookies::CookiesConnExt;

async fn handler(conn: trillium::Conn) -> trillium::Conn {
    let greeting = if let Some(name) = conn.cookies().get("user_name") {
        format!("welcome back, {}!", name.value())
    } else {
        "hello, stranger!".into()
    };
    conn.ok(greeting)
}

Setting cookies

conn.with_cookie(cookie) queues a Set-Cookie header for the response. The simplest form takes a (name, value) tuple:

use trillium_cookies::CookiesConnExt;
// ...
conn.with_cookie(("session_id", "abc123"))

For cookies with attributes, use Cookie::build from the re-exported cookie crate:

use trillium_cookies::{CookiesConnExt, cookie::{Cookie, SameSite}};

let cookie = Cookie::build(("preferences", "theme=dark"))
    .path("/")
    .secure(true)
    .http_only(true)
    .same_site(SameSite::Strict)
    .build();

conn.with_cookie(cookie)

Removing cookies

To delete a cookie, build a removal cookie.

conn.with_cookie(Cookie::build("session_id").removal().build())

Full example

use trillium::Conn;
use trillium_cookies::{CookiesConnExt, CookiesHandler};

pub fn main() {
    env_logger::init();

    trillium_smol::run((CookiesHandler::new(), |conn: Conn| async move {
        if let Some(cookie_value) = conn.cookies().get("some_cookie") {
            println!("current cookie value: {}", cookie_value.value());
        }

        conn.with_cookie(("some_cookie", "some-cookie-value"))
            .ok("ok!")
    }));
}