Installation

The session machinery is not included in the project scaffolded by pavex new. You need to go through a few steps to set it up.

Dependencies

The core session logic lives in a standalone crate, pavex_session.
Support for different session storage backends is provided by separate crates, such as pavex_session_sqlx and pavex_session_memory_store.

Choose a storage backend that fits your needs and then add the required dependencies to the Cargo.toml of your application crate:

PostgresIn-memory

[dependencies]
# [...]
pavex_session = "0.1"
pavex_session_sqlx = { version = "0.1", features = ["postgres"] }

[dependencies]
# [...]
pavex_session = "0.1"
pavex_session_memory_store = "0.1"

Blueprint

You need to add a few imports and middlewares to your Blueprint to get sessions up and running:

PostgresIn-memory

use pavex::{Blueprint, blueprint::from, cookie::INJECT_RESPONSE_COOKIES};
use pavex_session::FINALIZE_SESSION;

pub fn blueprint() -> Blueprint {
    let mut bp = Blueprint::new();

    bp.import(from![
        // Other imports [..]
        pavex, // (1)!
        pavex_session, // (2)!
        pavex_session_sqlx::postgres // (3)!
    ]);
    bp.post_process(FINALIZE_SESSION); // (4)!
    bp.post_process(INJECT_RESPONSE_COOKIES); // (5)!
    // [...]
}

1. pavex provides the core request/response types as well as cookies.
2. pavex_session provides the Session type and the machinery to manage the session lifecycle.
3. pavex_session_sqlx::postgres provides a Postgres-based session store implementation.
4. finalize_session looks at the current session state and decides whether a session cookie must be set or not on the outgoing response.
5. inject_response_cookies converts ResponseCookies into Set-Cookie headers on the response.
   It must execute after finalize_session, otherwise the session cookie will not be set. If you get the order wrong, the code generation process will fail.

use pavex::{Blueprint, blueprint::from, cookie::INJECT_RESPONSE_COOKIES};
use pavex_session::FINALIZE_SESSION;

pub fn blueprint() -> Blueprint {
    let mut bp = Blueprint::new();

    bp.import(from![
        // Other imports [..]
        pavex, // (1)!
        pavex_session, // (2)!
        pavex_session_memory_store // (3)!
    ]);
    bp.post_process(FINALIZE_SESSION); // (4)!
    bp.post_process(INJECT_RESPONSE_COOKIES); // (5)!
    // [...]
}

1. pavex provides the core request/response types as well as cookies.
2. pavex_session provides the Session type and the machinery to manage the session lifecycle.
3. pavex_session_memory_store provides the in-memory session store implementation.
4. finalize_session looks at the current session state and decides whether a session cookie must be set or not on the outgoing response.
5. inject_response_cookies converts ResponseCookies into Set-Cookie headers on the response.
   It must execute after finalize_session, otherwise the session cookie will not be set. If you get the order wrong, the code generation process will fail.

Sessions are built on top of cookies, so both must be installed for sessions to work correctly.