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  1. 13
      CHANGELOG.md
  2. 19
      Cargo.toml
  3. 66
      README.md
  4. 59
      examples/dog_list/main.rs
  5. 28
      examples/minimal/main.rs
  6. 73
      examples/visit_counter/main.rs
  7. 332
      src/lib.rs
  8. 206
      src/session.rs

@ -0,0 +1,13 @@
# [0.3.0]
- Update dependencies
- Added new example
- Port to rocket `0.5.0-rc.2`
# [0.2.2]
- Update dependencies
# [0.2.1]
- change from `thread_rng` to `OsRng` for better session ID entropy

@ -1,12 +1,21 @@
[package] [package]
name = "rocket_session" name = "rocket_session"
version = "0.1.0" version = "0.3.0"
authors = ["Ondřej Hruška <ondra@ondrovo.com>"] authors = ["Ondřej Hruška <ondra@ondrovo.com>"]
edition = "2018" edition = "2021"
license = "MIT"
description = "Rocket.rs plug-in for cookie-based sessions holding arbitrary data"
repository = "https://git.ondrovo.com/packages/rocket_session"
readme = "README.md"
keywords = ["rocket", "rocket-rs", "session", "cookie"]
categories = [
"web-programming",
"web-programming::http-server"
]
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies] [dependencies]
rand = "0.7.2" rand = "0.8"
rocket = "0.4.2" rocket = "0.5.0-rc.2"
parking_lot = "0.10.0" parking_lot = "0.12"

@ -2,54 +2,82 @@
Adding cookie-based sessions to a rocket application is extremely simple with this crate. Adding cookie-based sessions to a rocket application is extremely simple with this crate.
Sessions are used to share data between related requests, such as user authentication, shopping basket,
form values that failed validation for re-filling, etc.
## Configuration
The implementation is generic to support any type as session data: a custom struct, `String`, The implementation is generic to support any type as session data: a custom struct, `String`,
`HashMap`, or perhaps `serde_json::Value`. You're free to choose. `HashMap`, or perhaps `serde_json::Value`. You're free to choose.
The session expiry time is configurable through the Fairing. When a session expires, The session lifetime, cookie name, and other parameters can be configured by calling chained
the data associated with it is dropped. methods on the fairing. When a session expires, the data associated with it is dropped.
Example: `Session::fairing().with_lifetime(Duration::from_secs(15))`
## Usage
To use session in a route, first make sure you have the fairing attached by calling
`rocket.attach(Session::fairing())` at start-up, and then add something like `session : Session`
to the parameter list of your route(s). Everything else--session init, expiration, cookie
management--is done for you behind the scenes.
Session data is accessed in a closure run in the session context, using the `session.tap()`
method. This closure runs inside a per-session mutex, avoiding simultaneous mutation
from different requests. Try to *avoid lengthy operations inside the closure*,
as it effectively blocks any other request to session-enabled routes by the client.
## Basic example Every request to a session-enabled route extends the session's lifetime to the full
configured time (defaults to 1 hour). Automatic clean-up removes expired sessions to make sure
the session list does not waste memory.
## Examples
More examples are in the "examples" folder - run with `cargo run --example=NAME`
### Basic Example
This simple example uses u64 as the session variable; note that it can be a struct, map, or anything else, This simple example uses u64 as the session variable; note that it can be a struct, map, or anything else,
it just needs to implement `Send + Sync + Default`. it just needs to implement `Send + Sync + Default`.
```rust ```rust
#![feature(proc_macro_hygiene, decl_macro)] #[macro_use]
#[macro_use] extern crate rocket; extern crate rocket;
use std::time::Duration; type Session<'a> = rocket_session::Session<'a, u64>;
// It's convenient to define a type alias: #[launch]
pub type Session<'a> = rocket_session::Session<'a, u64>; fn rocket() -> _ {
rocket::build()
fn main() { .attach(Session::fairing())
rocket::ignite()
.attach(Session::fairing(Duration::from_secs(3600)))
.mount("/", routes![index]) .mount("/", routes![index])
.launch();
} }
#[get("/")] #[get("/")]
fn index(session: Session) -> String { fn index(session: Session) -> String {
let count = session.tap(|n| { let count = session.tap(|n| {
// Change the stored value (it is &mut) // Change the stored value (it is &mut)
*n += 1; *n += 1;
// Return something to the caller. // Return something to the caller.
// This can be any type, 'tap' is generic. // This can be any type, 'tap' is generic.
*n *n
}); });
format!("{} visits", count) format!("{} visits", count)
} }
``` ```
## Extending by a trait ## Extending Session by a Trait
The `tap` method is powerful, but sometimes you may wish for something more convenient. The `.tap()` method is powerful, but sometimes you may wish for something more convenient.
Here is an example of using a custom trait and the `json_dotpath` crate to implement Here is an example of using a custom trait and the `json_dotpath` crate to implement
a polymorphic store based on serde serialization: a polymorphic store based on serde serialization.
Note that this approach is prone to data races if you're accessing the session object multiple times per request,
since every method contains its own `.tap()`. It may be safer to simply call the `.dot_*()` methods manually in one shared closure.
```rust ```rust
use serde_json::Value; use serde_json::Value;

@ -0,0 +1,59 @@
#[macro_use]
extern crate rocket;
use rocket::response::content::RawHtml;
use rocket::response::Redirect;
type Session<'a> = rocket_session::Session<'a, Vec<String>>;
#[launch]
fn rocket() -> _ {
rocket::build()
.attach(Session::fairing())
.mount("/", routes![index, add, remove])
}
#[get("/")]
fn index(session: Session) -> RawHtml<String> {
let mut page = String::new();
page.push_str(
r#"
<!DOCTYPE html>
<h1>My Dogs</h1>
<form method="POST" action="/add">
Add Dog: <input type="text" name="name"> <input type="submit" value="Add">
</form>
<ul>
"#,
);
session.tap(|sess| {
for (n, dog) in sess.iter().enumerate() {
page.push_str(&format!(
r#"<li>&#x1F436; {} <a href="/remove/{}">Remove</a></li>"#,
dog, n
));
}
});
page.push_str("</ul>");
RawHtml(page)
}
#[post("/add", data = "<dog>")]
fn add(session: Session, dog: String) -> Redirect {
session.tap(move |sess| {
sess.push(dog);
});
Redirect::found("/")
}
#[get("/remove/<dog>")]
fn remove(session: Session, dog: usize) -> Redirect {
session.tap(|sess| {
if dog < sess.len() {
sess.remove(dog);
}
});
Redirect::found("/")
}

@ -0,0 +1,28 @@
#[macro_use]
extern crate rocket;
use std::time::Duration;
type Session<'a> = rocket_session::Session<'a, u64>;
#[launch]
fn rocket() -> _ {
// This session expires in 15 seconds as a demonstration of session configuration
rocket::build()
.attach(Session::fairing().with_lifetime(Duration::from_secs(15)))
.mount("/", routes![index])
}
#[get("/")]
fn index(session: Session) -> String {
let count = session.tap(|n| {
// Change the stored value (it is &mut)
*n += 1;
// Return something to the caller.
// This can be any type, 'tap' is generic.
*n
});
format!("{} visits", count)
}

@ -0,0 +1,73 @@
//! This demo is a page visit counter, with a custom cookie name, length, and expiry time.
//!
//! The expiry time is set to 10 seconds to illustrate how a session is cleared if inactive.
#[macro_use]
extern crate rocket;
use rocket::response::content::RawHtml;
use std::time::Duration;
#[derive(Default, Clone)]
struct SessionData {
visits1: usize,
visits2: usize,
}
// It's convenient to define a type alias:
type Session<'a> = rocket_session::Session<'a, SessionData>;
#[launch]
fn rocket() -> _ {
rocket::build()
.attach(
Session::fairing()
// 10 seconds of inactivity until session expires
// (wait 10s and refresh, the numbers will reset)
.with_lifetime(Duration::from_secs(10))
// custom cookie name and length
.with_cookie_name("my_cookie")
.with_cookie_len(20),
)
.mount("/", routes![index, about])
}
#[get("/")]
fn index(session: Session) -> RawHtml<String> {
// Here we build the entire response inside the 'tap' closure.
// While inside, the session is locked to parallel changes, e.g.
// from a different browser tab.
session.tap(|sess| {
sess.visits1 += 1;
RawHtml(format!(
r##"
<!DOCTYPE html>
<h1>Home</h1>
<a href="/">Refresh</a> &bull; <a href="/about/">go to About</a>
<p>Visits: home {}, about {}</p>
"##,
sess.visits1, sess.visits2
))
})
}
#[get("/about")]
fn about(session: Session) -> RawHtml<String> {
// Here we return a value from the tap function and use it below
let count = session.tap(|sess| {
sess.visits2 += 1;
sess.visits2
});
RawHtml(format!(
r##"
<!DOCTYPE html>
<h1>About</h1>
<a href="/about">Refresh</a> &bull; <a href="/">go home</a>
<p>Page visits: {}</p>
"##,
count
))
}

@ -1,2 +1,330 @@
mod session; use std::borrow::Cow;
pub use session::Session; use std::collections::HashMap;
use std::fmt::{self, Display, Formatter};
use std::marker::PhantomData;
use std::ops::Add;
use std::time::{Duration, Instant};
use parking_lot::{Mutex, RwLock, RwLockUpgradableReadGuard};
use rand::{rngs::OsRng, Rng};
use rocket::{
fairing::{self, Fairing, Info},
http::{Cookie, Status},
outcome::Outcome,
request::FromRequest,
Build, Request, Response, Rocket, State,
};
/// Session store (shared state)
#[derive(Debug)]
pub struct SessionStore<D>
where
D: 'static + Sync + Send + Default,
{
/// The internally mutable map of sessions
inner: RwLock<StoreInner<D>>,
// Session config
config: SessionConfig,
}
/// Session config object
#[derive(Debug, Clone)]
struct SessionConfig {
/// Sessions lifespan
lifespan: Duration,
/// Session cookie name
cookie_name: Cow<'static, str>,
/// Session cookie path
cookie_path: Cow<'static, str>,
/// Session ID character length
cookie_len: usize,
}
impl Default for SessionConfig {
fn default() -> Self {
Self {
lifespan: Duration::from_secs(3600),
cookie_name: "rocket_session".into(),
cookie_path: "/".into(),
cookie_len: 16,
}
}
}
/// Mutable object stored inside SessionStore behind a RwLock
#[derive(Debug)]
struct StoreInner<D>
where
D: 'static + Sync + Send + Default,
{
sessions: HashMap<String, Mutex<SessionInstance<D>>>,
last_expiry_sweep: Instant,
}
impl<D> Default for StoreInner<D>
where
D: 'static + Sync + Send + Default,
{
fn default() -> Self {
Self {
sessions: Default::default(),
// the first expiry sweep is scheduled one lifetime from start-up
last_expiry_sweep: Instant::now(),
}
}
}
/// Session, as stored in the sessions store
#[derive(Debug)]
struct SessionInstance<D>
where
D: 'static + Sync + Send + Default,
{
/// Data object
data: D,
/// Expiry
expires: Instant,
}
/// Session ID newtype for rocket's "local_cache"
#[derive(Clone, Debug)]
struct SessionID(String);
impl SessionID {
fn as_str(&self) -> &str {
self.0.as_str()
}
}
impl Display for SessionID {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
f.write_str(&self.0)
}
}
/// Session instance
///
/// To access the active session, simply add it as an argument to a route function.
///
/// Sessions are started, restored, or expired in the `FromRequest::from_request()` method
/// when a `Session` is prepared for one of the route functions.
#[derive(Debug)]
pub struct Session<'a, D>
where
D: 'static + Sync + Send + Default,
{
/// The shared state reference
store: &'a State<SessionStore<D>>,
/// Session ID
id: &'a SessionID,
}
#[rocket::async_trait]
impl<'r, D> FromRequest<'r> for Session<'r, D>
where
D: 'static + Sync + Send + Default,
{
type Error = ();
async fn from_request(request: &'r Request<'_>) -> Outcome<Self, (Status, Self::Error), ()> {
let store = request.guard::<&State<SessionStore<D>>>().await.unwrap();
Outcome::Success(Session {
id: request.local_cache(|| {
let store_ug = store.inner.upgradable_read();
// Resolve session ID
let id = request
.cookies()
.get(&store.config.cookie_name)
.map(|cookie| SessionID(cookie.value().to_string()));
let expires = Instant::now().add(store.config.lifespan);
if let Some(m) = id
.as_ref()
.and_then(|token| store_ug.sessions.get(token.as_str()))
{
// --- ID obtained from a cookie && session found in the store ---
let mut inner = m.lock();
if inner.expires <= Instant::now() {
// Session expired, reuse the ID but drop data.
inner.data = D::default();
}
// Session is extended by making a request with valid ID
inner.expires = expires;
id.unwrap()
} else {
// --- ID missing or session not found ---
// Get exclusive write access to the map
let mut store_wg = RwLockUpgradableReadGuard::upgrade(store_ug);
// This branch runs less often, and we already have write access,
// let's check if any sessions expired. We don't want to hog memory
// forever by abandoned sessions (e.g. when a client lost their cookie)
// Throttle by lifespan - e.g. sweep every hour
if store_wg.last_expiry_sweep.elapsed() > store.config.lifespan {
let now = Instant::now();
store_wg.sessions.retain(|_k, v| v.lock().expires > now);
store_wg.last_expiry_sweep = now;
}
// Find a new unique ID - we are still safely inside the write guard
let new_id = SessionID(loop {
let token: String = OsRng
.sample_iter(&rand::distributions::Alphanumeric)
.take(store.config.cookie_len)
.map(char::from)
.collect();
if !store_wg.sessions.contains_key(&token) {
break token;
}
});
store_wg.sessions.insert(
new_id.to_string(),
Mutex::new(SessionInstance {
data: Default::default(),
expires,
}),
);
new_id
}
}),
store,
})
}
}
impl<'a, D> Session<'a, D>
where
D: 'static + Sync + Send + Default,
{
/// Create the session fairing.
///
/// You can configure the session store by calling chained methods on the returned value
/// before passing it to `rocket.attach()`
pub fn fairing() -> SessionFairing<D> {
SessionFairing::<D>::new()
}
/// Clear session data (replace the value with default)
pub fn clear(&self) {
self.tap(|m| {
*m = D::default();
})
}
/// Access the session's data using a closure.
///
/// The closure is called with the data value as a mutable argument,
/// and can return any value to be is passed up to the caller.
pub fn tap<T>(&self, func: impl FnOnce(&mut D) -> T) -> T {
// Use a read guard, so other already active sessions are not blocked
// from accessing the store. New incoming clients may be blocked until
// the tap() call finishes
let store_rg = self.store.inner.read();
// Unlock the session's mutex.
// Expiry was checked and prolonged at the beginning of the request
let mut instance = store_rg
.sessions
.get(self.id.as_str())
.expect("Session data unexpectedly missing")
.lock();
func(&mut instance.data)
}
}
/// Fairing struct
#[derive(Default)]
pub struct SessionFairing<D>
where
D: 'static + Sync + Send + Default,
{
config: SessionConfig,
phantom: PhantomData<D>,
}
impl<D> SessionFairing<D>
where
D: 'static + Sync + Send + Default,
{
fn new() -> Self {
Self::default()
}
/// Set session lifetime (expiration time).
///
/// Call on the fairing before passing it to `rocket.attach()`
pub fn with_lifetime(mut self, time: Duration) -> Self {
self.config.lifespan = time;
self
}
/// Set session cookie name and length
///
/// Call on the fairing before passing it to `rocket.attach()`
pub fn with_cookie_name(mut self, name: impl Into<Cow<'static, str>>) -> Self {
self.config.cookie_name = name.into();
self
}
/// Set session cookie name and length
///
/// Call on the fairing before passing it to `rocket.attach()`
pub fn with_cookie_len(mut self, length: usize) -> Self {
self.config.cookie_len = length;
self
}
/// Set session cookie name and length
///
/// Call on the fairing before passing it to `rocket.attach()`
pub fn with_cookie_path(mut self, path: impl Into<Cow<'static, str>>) -> Self {
self.config.cookie_path = path.into();
self
}
}
#[rocket::async_trait]
impl<D> Fairing for SessionFairing<D>
where
D: 'static + Sync + Send + Default,
{
fn info(&self) -> Info {
Info {
name: "Session",
kind: fairing::Kind::Ignite | fairing::Kind::Response,
}
}
async fn on_ignite(&self, rocket: Rocket<Build>) -> Result<Rocket<Build>, Rocket<Build>> {
// install the store singleton
Ok(rocket.manage(SessionStore::<D> {
inner: Default::default(),
config: self.config.clone(),
}))
}
async fn on_response<'r>(&self, request: &'r Request<'_>, response: &mut Response) {
// send the session cookie, if session started
let session = request.local_cache(|| SessionID("".to_string()));
if !session.0.is_empty() {
response.adjoin_header(
Cookie::build(self.config.cookie_name.clone(), session.to_string())
.path("/")
.finish(),
);
}
}
}

@ -1,206 +0,0 @@
use parking_lot::RwLock;
use rand::Rng;
use rocket::{
fairing::{self, Fairing, Info},
http::{Cookie, Status},
request::FromRequest,
Outcome, Request, Response, Rocket, State,
};
use std::collections::HashMap;
use std::marker::PhantomData;
use std::ops::Add;
use std::time::{Duration, Instant};
const SESSION_COOKIE: &str = "SESSID";
const SESSION_ID_LEN: usize = 16;
/// Session, as stored in the sessions store
#[derive(Debug)]
struct SessionInstance<D>
where
D: 'static + Sync + Send + Default,
{
/// Data object
data: D,
/// Expiry
expires: Instant,
}
/// Session store (shared state)
#[derive(Default, Debug)]
pub struct SessionStore<D>
where
D: 'static + Sync + Send + Default,
{
/// The internaly mutable map of sessions
inner: RwLock<HashMap<String, SessionInstance<D>>>,
/// Sessions lifespan
lifespan: Duration,
}
impl<D> SessionStore<D>
where
D: 'static + Sync + Send + Default,
{
/// Remove all expired sessions
pub fn remove_expired(&self) {
let now = Instant::now();
self.inner.write().retain(|_k, v| v.expires > now);
}
}
/// Session ID newtype for rocket's "local_cache"
#[derive(PartialEq, Hash, Clone, Debug)]
struct SessionID(String);
impl<'a, 'r> FromRequest<'a, 'r> for &'a SessionID {
type Error = ();
fn from_request(request: &'a Request<'r>) -> Outcome<Self, (Status, Self::Error), ()> {
Outcome::Success(request.local_cache(|| {
if let Some(cookie) = request.cookies().get(SESSION_COOKIE) {
SessionID(cookie.value().to_string()) // FIXME avoid cloning (cow?)
} else {
SessionID(
rand::thread_rng()
.sample_iter(&rand::distributions::Alphanumeric)
.take(16)
.collect(),
)
}
}))
}
}
/// Session instance
#[derive(Debug)]
pub struct Session<'a, D>
where
D: 'static + Sync + Send + Default,
{
/// The shared state reference
store: State<'a, SessionStore<D>>,
/// Session ID
id: &'a SessionID,
}
impl<'a, 'r, D> FromRequest<'a, 'r> for Session<'a, D>
where
D: 'static + Sync + Send + Default,
{
type Error = ();
fn from_request(request: &'a Request<'r>) -> Outcome<Self, (Status, Self::Error), ()> {
Outcome::Success(Session {
id: request.local_cache(|| {
if let Some(cookie) = request.cookies().get(SESSION_COOKIE) {
SessionID(cookie.value().to_string())
} else {
SessionID(
rand::thread_rng()
.sample_iter(&rand::distributions::Alphanumeric)
.take(SESSION_ID_LEN)
.collect(),
)
}
}),
store: request.guard().unwrap(),
})
}
}
impl<'a, D> Session<'a, D>
where
D: 'static + Sync + Send + Default,
{
/// Get the fairing object
pub fn fairing(lifespan: Duration) -> impl Fairing {
SessionFairing::<D> {
lifespan,
_phantom: PhantomData,
}
}
/// Access the session store
pub fn get_store(&self) -> &SessionStore<D> {
&self.store
}
/// Set the session object to its default state
pub fn reset(&self) {
self.tap(|m| {
*m = D::default();
})
}
/// Renew the session without changing any data
pub fn renew(&self) {
self.tap(|_| ())
}
/// Run a closure with a mutable reference to the session object.
/// The closure's return value is send to the caller.
pub fn tap<T>(&self, func: impl FnOnce(&mut D) -> T) -> T {
let mut wg = self.store.inner.write();
if let Some(instance) = wg.get_mut(&self.id.0) {
// wipe session data if expired
if instance.expires <= Instant::now() {
instance.data = D::default();
}
// update expiry timestamp
instance.expires = Instant::now().add(self.store.lifespan);
func(&mut instance.data)
} else {
// no object in the store yet, start fresh
let mut data = D::default();
let result = func(&mut data);
wg.insert(
self.id.0.clone(),
SessionInstance {
data,
expires: Instant::now().add(self.store.lifespan),
},
);
result
}
}
}
/// Fairing struct
struct SessionFairing<D>
where
D: 'static + Sync + Send + Default,
{
lifespan: Duration,
_phantom: PhantomData<D>,
}
impl<D> Fairing for SessionFairing<D>
where
D: 'static + Sync + Send + Default,
{
fn info(&self) -> Info {
Info {
name: "Session",
kind: fairing::Kind::Attach | fairing::Kind::Response,
}
}
fn on_attach(&self, rocket: Rocket) -> Result<Rocket, Rocket> {
Ok(rocket.manage(SessionStore::<D> {
inner: Default::default(),
lifespan: self.lifespan,
}))
}
fn on_response<'r>(&self, request: &'r Request, response: &mut Response) {
let session = request.local_cache(|| SessionID("".to_string()));
if !session.0.is_empty() {
response.adjoin_header(Cookie::build(SESSION_COOKIE, session.0.clone()).finish());
}
}
}
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