vendor assets with versionning

src/assets.rs

@@ -0,0 +1,79 @@
+use std::collections::HashMap;
+use std::sync::LazyLock;
+
+use sha2::{Digest, Sha256};
+
+/// A single static asset: its embedded bytes and a content hash used to
+/// version its URL.
+pub struct StaticAsset {
+    pub data: &'static [u8],
+    pub hash: String,
+}
+
+/// A registry of the app's static assets, keyed by filename. Each asset's
+/// content hash is computed once on first use and cached, so the versioned URL
+/// changes automatically whenever the underlying file changes.
+pub struct StaticAssetStore {
+    assets: HashMap<&'static str, StaticAsset>,
+}
+
+impl StaticAssetStore {
+    fn new(entries: &[(&'static str, &'static [u8])]) -> Self {
+        let assets = entries
+            .iter()
+            .map(|(name, data)| {
+                let hash = content_hash(data);
+                (*name, StaticAsset { data, hash })
+            })
+            .collect();
+        Self { assets }
+    }
+
+    /// Looks up an asset by its filename (e.g. `"style.css"`).
+    pub fn get(&self, name: &str) -> Option<&StaticAsset> {
+        self.assets.get(name)
+    }
+
+    /// Returns the versioned URL for an asset, e.g. `/static/style.css?v=<hash>`.
+    pub fn url(&self, name: &str) -> Option<String> {
+        self.assets
+            .get(name)
+            .map(|asset| format!("/static/{name}?v={}", asset.hash))
+    }
+}
+
+fn content_hash(data: &[u8]) -> String {
+    let mut hasher = Sha256::new();
+    hasher.update(data);
+    hex::encode(hasher.finalize())
+}
+
+/// Constructs a `StaticAssetStore` from `name => path` pairs, embedding each
+/// file's bytes at compile time via `include_bytes!`.
+macro_rules! static_assets {
+    ($($name:literal => $path:literal),* $(,)?) => {
+        StaticAssetStore::new(&[
+            $(($name, include_bytes!($path))),*
+        ])
+    };
+}
+
+/// The app's static assets, loaded once on first use.
+pub static STORE: LazyLock<StaticAssetStore> = LazyLock::new(|| {
+    static_assets! {
+        "style.css" => "../static/style.css",
+        "passkey-login.js" => "../static/passkey-login.js",
+        "passkey-register.js" => "../static/passkey-register.js",
+        "password-toggle.js" => "../static/password-toggle.js",
+        "htmx.min.js" => "../static/htmx.min.js",
+        "htmx-ws.min.js" => "../static/htmx-ws.min.js",
+    }
+});
+
+/// Returns the versioned URL for a known asset, panicking if the name isn't
+/// registered (a programmer error, since these are compile-time constants).
+pub fn url(name: &str) -> String {
+    STORE
+        .url(name)
+        .unwrap_or_else(|| panic!("unknown static asset: {name}"))
+}

src/http.rs

@@ -20,19 +20,13 @@ use thiserror::Error;
 use tower_http::trace::{DefaultMakeSpan, DefaultOnResponse, TraceLayer};
 use tracing::{Level, error, warn};
 
+use crate::assets;
 use crate::domain::{DomainError, SessionUser};
 use crate::ports::{HubEvent, RealtimeNotifier};
 use crate::services::{AuthService, InvitationService, ListService, MealService};
 use crate::views;
 use crate::webauthn::WebAuthnService;
 
-/// The contents of `static/`, embedded into the binary at compile time so the
-/// app can be shipped as a single executable without a separate static directory.
-const STYLE_CSS: &[u8] = include_bytes!("../static/style.css");
-const PASSKEY_LOGIN_JS: &[u8] = include_bytes!("../static/passkey-login.js");
-const PASSKEY_REGISTER_JS: &[u8] = include_bytes!("../static/passkey-register.js");
-const PASSWORD_TOGGLE_JS: &[u8] = include_bytes!("../static/password-toggle.js");
-
 #[derive(Clone)]
 pub struct AppState {
     pub auth: Arc<AuthService>,
@@ -340,15 +334,24 @@ async fn home() -> Redirect {
 }
 
 /// Serves a file embedded in the binary from the `static/` folder.
+///
+/// Every asset is served with an immutable, long-lived cache header. Because
+/// the HTML references each asset under a URL that is versioned by its content
+/// hash, a changed file gets a new URL and the cache is never stale.
 async fn static_asset(Path(path): Path<String>) -> Response {
-    let (mime, data) = match path.as_str() {
-        "style.css" => ("text/css", STYLE_CSS),
-        "passkey-login.js" => ("application/javascript", PASSKEY_LOGIN_JS),
-        "passkey-register.js" => ("application/javascript", PASSKEY_REGISTER_JS),
-        "password-toggle.js" => ("application/javascript", PASSWORD_TOGGLE_JS),
-        _ => return StatusCode::NOT_FOUND.into_response(),
+    let Some(asset) = assets::STORE.get(&path) else {
+        return StatusCode::NOT_FOUND.into_response();
     };
-    ([(header::CONTENT_TYPE, mime)], data).into_response()
+    let mime = match path.as_str() {
+        "style.css" => "text/css",
+        _ => "application/javascript",
+    };
+    let mut response = ([(header::CONTENT_TYPE, mime)], asset.data).into_response();
+    response.headers_mut().insert(
+        header::CACHE_CONTROL,
+        HeaderValue::from_static("public, max-age=31536000, immutable"),
+    );
+    response
 }
 
 async fn log_response_status(request: Request, next: Next) -> Response {

src/main.rs

@@ -1,3 +1,4 @@
+mod assets;
 mod domain;
 mod http;
 mod hub;

src/views.rs

@@ -37,8 +37,8 @@ pub fn login_page(error: Option<&str>, invite: Option<&str>) -> Markup {
                 button id="passkey-login" class="button button-secondary" type="button" { "Sign in with a passkey" }
                 p class="auth-switch" { "Need an account? " a href="/register" { "Create one" } }
             }
-            script src="/static/password-toggle.js" {}
-            script src="/static/passkey-login.js" {}
+            script src=(crate::assets::url("password-toggle.js")) {}
+            script src=(crate::assets::url("passkey-login.js")) {}
         },
     )
 }
@@ -72,7 +72,7 @@ pub fn register_page(error: Option<&str>, invite: Option<&str>) -> Markup {
                 }
                 p class="auth-switch" { "Already have an account? " a href="/login" { "Sign in" } }
             }
-            script src="/static/password-toggle.js" {}
+            script src=(crate::assets::url("password-toggle.js")) {}
         },
     )
 }
@@ -164,8 +164,8 @@ pub fn account_page(
                     }
                 }
             }
-            script src="/static/password-toggle.js" {}
-            script src="/static/passkey-register.js" {}
+            script src=(crate::assets::url("password-toggle.js")) {}
+            script src=(crate::assets::url("passkey-register.js")) {}
         },
     )
 }
@@ -1308,9 +1308,9 @@ fn page(title: &str, user: Option<&User>, content: Markup) -> Markup {
                 meta charset="utf-8";
                 meta name="viewport" content="width=device-width, initial-scale=1";
                 title { (title) " · Sustenance" }
-                link rel="stylesheet" href="/static/style.css";
-                script src="https://unpkg.com/htmx.org@2.0.10" {}
-                script src="https://unpkg.com/htmx-ext-ws@2.0.4/ws.js" {}
+                link rel="stylesheet" href=(crate::assets::url("style.css"));
+                script src=(crate::assets::url("htmx.min.js")) {}
+                script src=(crate::assets::url("htmx-ws.min.js")) {}
             }
             body hx-boost="true" {
                 header class="site-header" {