OXYGENHUB
# de505df5cf8d oxygenhub / crates / hub / src / auth / viewer.rs
2.8 KiB · Rust · last changed Milestone 0.2: accounts and access 1 month ago source blame history raw
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//! Who is asking: the session cookie resolved to an account, as an axum
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//! extractor every page handler takes.
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use super::{csrf_token, mac_equal, session_value, SESSION_COOKIE};
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use crate::db::{self, accounts::Account};
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use crate::Shared;
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use axum::extract::FromRequestParts;
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use axum::http::request::Parts;
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use axum::http::{header, HeaderMap};
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use std::convert::Infallible;
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#[derive(Clone, Debug)]
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pub struct ViewerAccount {
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    pub account: Account,
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    /// The cookie value, which CSRF tokens are bound to.
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    pub session: String,
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    pub csrf: String,
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}
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/// The signed-in account, if any. Never fails: anonymous is a valid viewer.
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#[derive(Clone, Debug, Default)]
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pub struct Viewer(pub Option<ViewerAccount>);
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impl Viewer {
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    pub fn account(&self) -> Option<&Account> {
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        self.0.as_ref().map(|v| &v.account)
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    }
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    pub fn signed_in(&self) -> bool {
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        self.0.is_some()
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    }
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    pub fn is_admin(&self) -> bool {
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        self.account().is_some_and(|a| a.is_admin)
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    }
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    pub fn csrf(&self) -> &str {
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        self.0.as_ref().map(|v| v.csrf.as_str()).unwrap_or("")
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    }
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    /// Whether a submitted CSRF token belongs to this session.
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    pub fn csrf_ok(&self, token: &str) -> bool {
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        self.0.as_ref().is_some_and(|v| mac_equal(&v.csrf, token))
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    }
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}
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/// The value of a named cookie in the request.
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pub fn cookie(headers: &HeaderMap, name: &str) -> Option<String> {
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    headers.get_all(header::COOKIE).iter().filter_map(|v| v.to_str().ok()).flat_map(|line| line.split(';')).find_map(|kv| {
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        let (k, v) = kv.trim().split_once('=')?;
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        (k == name).then(|| v.trim().to_string())
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    })
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}
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/// Resolve a session cookie value to its account.
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pub async fn resolve(app: &Shared, value: &str) -> Option<ViewerAccount> {
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    let (username, mac) = value.rsplit_once('.')?;
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    let account = db::accounts::account_by_name(&app.db, username).await.ok()??;
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    if account.banned {
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        return None;
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    }
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    let expected = session_value(&app.cookie_key, &account.username, &account.session_salt);
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    let (_, expected_mac) = expected.rsplit_once('.')?;
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    if !mac_equal(expected_mac, mac) {
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        return None;
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    }
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    let csrf = csrf_token(&app.cookie_key, &expected);
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    Some(ViewerAccount { account, session: expected, csrf })
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}
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impl FromRequestParts<Shared> for Viewer {
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    type Rejection = Infallible;
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    async fn from_request_parts(parts: &mut Parts, app: &Shared) -> Result<Viewer, Infallible> {
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        let Some(value) = cookie(&parts.headers, SESSION_COOKIE) else { return Ok(Viewer(None)) };
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        let viewer = resolve(app, &value).await;
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        if let Some(v) = &viewer {
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            let pool = app.db.clone();
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            let id = v.account.id;
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            tokio::spawn(async move {
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                let _ = db::accounts::touch_seen(&pool, id).await;
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            });
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        }
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        Ok(Viewer(viewer))
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    }
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}