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use std::{collections::HashMap, fmt, future::Future, pin::Pin, rc::Rc};
use actix_utils::future::{ready, Ready};
use actix_web::{
body::MessageBody,
cookie::{Cookie, CookieJar, Key},
dev::{forward_ready, ResponseHead, Service, ServiceRequest, ServiceResponse, Transform},
http::header::{HeaderValue, SET_COOKIE},
HttpResponse,
};
use anyhow::Context;
use crate::{
config::{
self, Configuration, CookieConfiguration, CookieContentSecurity, SessionMiddlewareBuilder,
TtlExtensionPolicy,
},
storage::{LoadError, SessionKey, SessionStore},
Session, SessionStatus,
};
/// A middleware for session management in Actix Web applications.
///
/// [`SessionMiddleware`] takes care of a few jobs:
///
/// - Instructs the session storage backend to create/update/delete/retrieve the state attached to
/// a session according to its status and the operations that have been performed against it;
/// - Set/remove a cookie, on the client side, to enable a user to be consistently associated with
/// the same session across multiple HTTP requests.
///
/// Use [`SessionMiddleware::new`] to initialize the session framework using the default parameters.
/// To create a new instance of [`SessionMiddleware`] you need to provide:
///
/// - an instance of the session storage backend you wish to use (i.e. an implementation of
/// [`SessionStore`]);
/// - a secret key, to sign or encrypt the content of client-side session cookie.
///
/// # How did we choose defaults?
/// You should not regret adding `actix-session` to your dependencies and going to production using
/// the default configuration. That is why, when in doubt, we opt to use the most secure option for
/// each configuration parameter.
///
/// We expose knobs to change the default to suit your needs—i.e., if you know what you are doing,
/// we will not stop you. But being a subject-matter expert should not be a requirement to deploy
/// reasonably secure implementation of sessions.
///
/// # Examples
/// ```no_run
/// use actix_web::{web, App, HttpServer, HttpResponse, Error};
/// use actix_session::{Session, SessionMiddleware, storage::RedisActorSessionStore};
/// use actix_web::cookie::Key;
///
/// // The secret key would usually be read from a configuration file/environment variables.
/// fn get_secret_key() -> Key {
/// # todo!()
/// // [...]
/// }
///
/// #[actix_web::main]
/// async fn main() -> std::io::Result<()> {
/// let secret_key = get_secret_key();
/// let redis_connection_string = "127.0.0.1:6379";
/// HttpServer::new(move ||
/// App::new()
/// // Add session management to your application using Redis for session state storage
/// .wrap(
/// SessionMiddleware::new(
/// RedisActorSessionStore::new(redis_connection_string),
/// secret_key.clone()
/// )
/// )
/// .default_service(web::to(|| HttpResponse::Ok())))
/// .bind(("127.0.0.1", 8080))?
/// .run()
/// .await
/// }
/// ```
///
/// If you want to customise use [`builder`](Self::builder) instead of [`new`](Self::new):
///
/// ```no_run
/// use actix_web::{App, cookie::{Key, time}, Error, HttpResponse, HttpServer, web};
/// use actix_session::{Session, SessionMiddleware, storage::RedisActorSessionStore};
/// use actix_session::config::PersistentSession;
///
/// // The secret key would usually be read from a configuration file/environment variables.
/// fn get_secret_key() -> Key {
/// # todo!()
/// // [...]
/// }
///
/// #[actix_web::main]
/// async fn main() -> std::io::Result<()> {
/// let secret_key = get_secret_key();
/// let redis_connection_string = "127.0.0.1:6379";
/// HttpServer::new(move ||
/// App::new()
/// // Customise session length!
/// .wrap(
/// SessionMiddleware::builder(
/// RedisActorSessionStore::new(redis_connection_string),
/// secret_key.clone()
/// )
/// .session_lifecycle(
/// PersistentSession::default()
/// .session_ttl(time::Duration::days(5))
/// )
/// .build(),
/// )
/// .default_service(web::to(|| HttpResponse::Ok())))
/// .bind(("127.0.0.1", 8080))?
/// .run()
/// .await
/// }
/// ```
#[derive(Clone)]
pub struct SessionMiddleware<Store: SessionStore> {
storage_backend: Rc<Store>,
configuration: Rc<Configuration>,
}
impl<Store: SessionStore> SessionMiddleware<Store> {
/// Use [`SessionMiddleware::new`] to initialize the session framework using the default
/// parameters.
///
/// To create a new instance of [`SessionMiddleware`] you need to provide:
/// - an instance of the session storage backend you wish to use (i.e. an implementation of
/// [`SessionStore`]);
/// - a secret key, to sign or encrypt the content of client-side session cookie.
pub fn new(store: Store, key: Key) -> Self {
Self::builder(store, key).build()
}
/// A fluent API to configure [`SessionMiddleware`].
///
/// It takes as input the two required inputs to create a new instance of [`SessionMiddleware`]:
/// - an instance of the session storage backend you wish to use (i.e. an implementation of
/// [`SessionStore`]);
/// - a secret key, to sign or encrypt the content of client-side session cookie.
pub fn builder(store: Store, key: Key) -> SessionMiddlewareBuilder<Store> {
SessionMiddlewareBuilder::new(store, config::default_configuration(key))
}
pub(crate) fn from_parts(store: Store, configuration: Configuration) -> Self {
Self {
storage_backend: Rc::new(store),
configuration: Rc::new(configuration),
}
}
}
impl<S, B, Store> Transform<S, ServiceRequest> for SessionMiddleware<Store>
where
S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = actix_web::Error> + 'static,
S::Future: 'static,
B: MessageBody + 'static,
Store: SessionStore + 'static,
{
type Response = ServiceResponse<B>;
type Error = actix_web::Error;
type Transform = InnerSessionMiddleware<S, Store>;
type InitError = ();
type Future = Ready<Result<Self::Transform, Self::InitError>>;
fn new_transform(&self, service: S) -> Self::Future {
ready(Ok(InnerSessionMiddleware {
service: Rc::new(service),
configuration: Rc::clone(&self.configuration),
storage_backend: Rc::clone(&self.storage_backend),
}))
}
}
/// Short-hand to create an `actix_web::Error` instance that will result in an `Internal Server
/// Error` response while preserving the error root cause (e.g. in logs).
fn e500<E: fmt::Debug + fmt::Display + 'static>(err: E) -> actix_web::Error {
// We do not use `actix_web::error::ErrorInternalServerError` because we do not want to
// leak internal implementation details to the caller.
//
// `actix_web::error::ErrorInternalServerError` includes the error Display representation
// as body of the error responses, leading to messages like "There was an issue persisting
// the session state" reaching API clients. We don't want that, we want opaque 500s.
actix_web::error::InternalError::from_response(
err,
HttpResponse::InternalServerError().finish(),
)
.into()
}
#[doc(hidden)]
#[non_exhaustive]
pub struct InnerSessionMiddleware<S, Store: SessionStore + 'static> {
service: Rc<S>,
configuration: Rc<Configuration>,
storage_backend: Rc<Store>,
}
impl<S, B, Store> Service<ServiceRequest> for InnerSessionMiddleware<S, Store>
where
S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = actix_web::Error> + 'static,
S::Future: 'static,
Store: SessionStore + 'static,
{
type Response = ServiceResponse<B>;
type Error = actix_web::Error;
#[allow(clippy::type_complexity)]
type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>>>>;
forward_ready!(service);
fn call(&self, mut req: ServiceRequest) -> Self::Future {
let service = Rc::clone(&self.service);
let storage_backend = Rc::clone(&self.storage_backend);
let configuration = Rc::clone(&self.configuration);
Box::pin(async move {
let session_key = extract_session_key(&req, &configuration.cookie);
let (session_key, session_state) =
load_session_state(session_key, storage_backend.as_ref()).await?;
Session::set_session(&mut req, session_state);
let mut res = service.call(req).await?;
let (status, session_state) = Session::get_changes(&mut res);
match session_key {
None => {
// we do not create an entry in the session store if there is no state attached
// to a fresh session
if !session_state.is_empty() {
let session_key = storage_backend
.save(session_state, &configuration.session.state_ttl)
.await
.map_err(e500)?;
set_session_cookie(
res.response_mut().head_mut(),
session_key,
&configuration.cookie,
)
.map_err(e500)?;
}
}
Some(session_key) => {
match status {
SessionStatus::Changed => {
let session_key = storage_backend
.update(
session_key,
session_state,
&configuration.session.state_ttl,
)
.await
.map_err(e500)?;
set_session_cookie(
res.response_mut().head_mut(),
session_key,
&configuration.cookie,
)
.map_err(e500)?;
}
SessionStatus::Purged => {
storage_backend.delete(&session_key).await.map_err(e500)?;
delete_session_cookie(
res.response_mut().head_mut(),
&configuration.cookie,
)
.map_err(e500)?;
}
SessionStatus::Renewed => {
storage_backend.delete(&session_key).await.map_err(e500)?;
let session_key = storage_backend
.save(session_state, &configuration.session.state_ttl)
.await
.map_err(e500)?;
set_session_cookie(
res.response_mut().head_mut(),
session_key,
&configuration.cookie,
)
.map_err(e500)?;
}
SessionStatus::Unchanged => {
if matches!(
configuration.ttl_extension_policy,
TtlExtensionPolicy::OnEveryRequest
) {
storage_backend
.update_ttl(&session_key, &configuration.session.state_ttl)
.await
.map_err(e500)?;
if configuration.cookie.max_age.is_some() {
set_session_cookie(
res.response_mut().head_mut(),
session_key,
&configuration.cookie,
)
.map_err(e500)?;
}
}
}
};
}
}
Ok(res)
})
}
}
/// Examines the session cookie attached to the incoming request, if there is one, and tries
/// to extract the session key.
///
/// It returns `None` if there is no session cookie or if the session cookie is considered invalid
/// (e.g., when failing a signature check).
fn extract_session_key(req: &ServiceRequest, config: &CookieConfiguration) -> Option<SessionKey> {
let cookies = req.cookies().ok()?;
let session_cookie = cookies
.iter()
.find(|&cookie| cookie.name() == config.name)?;
let mut jar = CookieJar::new();
jar.add_original(session_cookie.clone());
let verification_result = match config.content_security {
CookieContentSecurity::Signed => jar.signed(&config.key).get(&config.name),
CookieContentSecurity::Private => jar.private(&config.key).get(&config.name),
};
if verification_result.is_none() {
tracing::warn!(
"The session cookie attached to the incoming request failed to pass cryptographic \
checks (signature verification/decryption)."
);
}
match verification_result?.value().to_owned().try_into() {
Ok(session_key) => Some(session_key),
Err(err) => {
tracing::warn!(
error.message = %err,
error.cause_chain = ?err,
"Invalid session key, ignoring."
);
None
}
}
}
async fn load_session_state<Store: SessionStore>(
session_key: Option<SessionKey>,
storage_backend: &Store,
) -> Result<(Option<SessionKey>, HashMap<String, String>), actix_web::Error> {
if let Some(session_key) = session_key {
match storage_backend.load(&session_key).await {
Ok(state) => {
if let Some(state) = state {
Ok((Some(session_key), state))
} else {
// We discard the existing session key given that the state attached to it can
// no longer be found (e.g. it expired or we suffered some data loss in the
// storage). Regenerating the session key will trigger the `save` workflow
// instead of the `update` workflow if the session state is modified during the
// lifecycle of the current request.
tracing::info!(
"No session state has been found for a valid session key, creating a new \
empty session."
);
Ok((None, HashMap::new()))
}
}
Err(err) => match err {
LoadError::Deserialization(err) => {
tracing::warn!(
error.message = %err,
error.cause_chain = ?err,
"Invalid session state, creating a new empty session."
);
Ok((Some(session_key), HashMap::new()))
}
LoadError::Other(err) => Err(e500(err)),
},
}
} else {
Ok((None, HashMap::new()))
}
}
fn set_session_cookie(
response: &mut ResponseHead,
session_key: SessionKey,
config: &CookieConfiguration,
) -> Result<(), anyhow::Error> {
let value: String = session_key.into();
let mut cookie = Cookie::new(config.name.clone(), value);
cookie.set_secure(config.secure);
cookie.set_http_only(config.http_only);
cookie.set_same_site(config.same_site);
cookie.set_path(config.path.clone());
if let Some(max_age) = config.max_age {
cookie.set_max_age(max_age);
}
if let Some(ref domain) = config.domain {
cookie.set_domain(domain.clone());
}
let mut jar = CookieJar::new();
match config.content_security {
CookieContentSecurity::Signed => jar.signed_mut(&config.key).add(cookie),
CookieContentSecurity::Private => jar.private_mut(&config.key).add(cookie),
}
// set cookie
let cookie = jar.delta().next().unwrap();
let val = HeaderValue::from_str(&cookie.encoded().to_string())
.context("Failed to attach a session cookie to the outgoing response")?;
response.headers_mut().append(SET_COOKIE, val);
Ok(())
}
fn delete_session_cookie(
response: &mut ResponseHead,
config: &CookieConfiguration,
) -> Result<(), anyhow::Error> {
let removal_cookie = Cookie::build(config.name.clone(), "")
.path(config.path.clone())
.secure(config.secure)
.http_only(config.http_only)
.same_site(config.same_site);
let mut removal_cookie = if let Some(ref domain) = config.domain {
removal_cookie.domain(domain)
} else {
removal_cookie
}
.finish();
removal_cookie.make_removal();
let val = HeaderValue::from_str(&removal_cookie.to_string())
.context("Failed to attach a session removal cookie to the outgoing response")?;
response.headers_mut().append(SET_COOKIE, val);
Ok(())
}