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|
use chrono::TimeDelta;
use futures::{
future,
stream::{self, StreamExt as _},
Stream,
};
use sqlx::sqlite::SqlitePool;
use super::{
repo::auth::Provider as _, repo::Provider as _, Broadcaster, Event as TokenEvent, Id, Secret,
};
use crate::{
clock::DateTime,
db::NotFound as _,
login::{Login, Password},
};
pub struct Tokens<'a> {
db: &'a SqlitePool,
token_events: &'a Broadcaster,
}
impl<'a> Tokens<'a> {
pub const fn new(db: &'a SqlitePool, token_events: &'a Broadcaster) -> Self {
Self { db, token_events }
}
pub async fn login(
&self,
name: &str,
password: &Password,
login_at: &DateTime,
) -> Result<(Login, Secret), LoginError> {
let mut tx = self.db.begin().await?;
let (login, stored_hash) = tx
.auth()
.for_name(name)
.await
.optional()?
.ok_or(LoginError::Rejected)?;
// Split the transaction here to avoid holding the tx open (potentially blocking
// other writes) while we do the fairly expensive task of verifying the
// password. It's okay if the token issuance transaction happens some notional
// amount of time after retrieving the login, as inserting the token will fail
// if the account is deleted during that time.
tx.commit().await?;
let snapshot = login.as_snapshot().ok_or(LoginError::Rejected)?;
let token = if stored_hash.verify(password)? {
let mut tx = self.db.begin().await?;
let token = tx.tokens().issue(&login, login_at).await?;
tx.commit().await?;
token
} else {
Err(LoginError::Rejected)?
};
Ok((snapshot, token))
}
pub async fn validate(
&self,
secret: &Secret,
used_at: &DateTime,
) -> Result<(Id, Login), ValidateError> {
let mut tx = self.db.begin().await?;
let login = tx
.tokens()
.validate(secret, used_at)
.await
.not_found(|| ValidateError::InvalidToken)?;
tx.commit().await?;
Ok(login)
}
pub async fn limit_stream<E>(
&self,
token: Id,
events: impl Stream<Item = E> + std::fmt::Debug,
) -> Result<impl Stream<Item = E> + std::fmt::Debug, ValidateError>
where
E: std::fmt::Debug,
{
// Subscribe, first.
let token_events = self.token_events.subscribe();
// Check that the token is valid at this point in time, second. If it is, then
// any future revocations will appear in the subscription. If not, bail now.
//
// It's possible, otherwise, to get to this point with a token that _was_ valid
// at the start of the request, but which was invalided _before_ the
// `subscribe()` call. In that case, the corresponding revocation event will
// simply be missed, since the `token_events` stream subscribed after the fact.
// This check cancels guarding the stream here.
//
// Yes, this is a weird niche edge case. Most things don't double-check, because
// they aren't expected to run long enough for the token's revocation to
// matter. Supervising a stream, on the other hand, will run for a
// _long_ time; if we miss the race here, we'll never actually carry out the
// supervision.
let mut tx = self.db.begin().await?;
tx.tokens()
.require(&token)
.await
.not_found(|| ValidateError::InvalidToken)?;
tx.commit().await?;
// Then construct the guarded stream. First, project both streams into
// `GuardedEvent`.
let token_events = token_events
.filter(move |event| {
future::ready(matches!(event, TokenEvent::Revoked(id) if id == &token))
})
.map(|_| GuardedEvent::TokenRevoked);
let events = events.map(|event| GuardedEvent::Event(event));
// Merge the two streams, then unproject them, stopping at
// `GuardedEvent::TokenRevoked`.
let stream = stream::select(token_events, events).scan((), |(), event| {
future::ready(match event {
GuardedEvent::Event(event) => Some(event),
GuardedEvent::TokenRevoked => None,
})
});
Ok(stream)
}
pub async fn expire(&self, relative_to: &DateTime) -> Result<(), sqlx::Error> {
// Somewhat arbitrarily, expire after 7 days.
let expire_at = relative_to.to_owned() - TimeDelta::days(7);
let mut tx = self.db.begin().await?;
let tokens = tx.tokens().expire(&expire_at).await?;
tx.commit().await?;
for event in tokens.into_iter().map(TokenEvent::Revoked) {
self.token_events.broadcast(event);
}
Ok(())
}
pub async fn logout(&self, token: &Id) -> Result<(), ValidateError> {
let mut tx = self.db.begin().await?;
tx.tokens().revoke(token).await?;
tx.commit().await?;
self.token_events
.broadcast(TokenEvent::Revoked(token.clone()));
Ok(())
}
}
#[derive(Debug, thiserror::Error)]
pub enum LoginError {
#[error("invalid login")]
Rejected,
#[error(transparent)]
Database(#[from] sqlx::Error),
#[error(transparent)]
PasswordHash(#[from] password_hash::Error),
}
#[derive(Debug, thiserror::Error)]
pub enum ValidateError {
#[error("invalid token")]
InvalidToken,
#[error(transparent)]
Database(#[from] sqlx::Error),
}
#[derive(Debug)]
enum GuardedEvent<E> {
TokenRevoked,
Event(E),
}
|
