Tonight

server-rs/src/main.rs

@@ -19,6 +19,7 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use anyhow::{bail, Context};
+use axum::http::{header, HeaderValue};
 use axum::middleware;
 use axum::routing::{any, get, patch, post};
 use axum::Router;
@@ -37,6 +38,67 @@ use tracing_subscriber::EnvFilter;
 
 use state::{AppState, SharedState};
 
+fn is_api_path(path: &str) -> bool {
+    path.starts_with("/api/")
+        || path.starts_with("/pb/")
+        || path.starts_with("/s/")
+        || matches!(path, "/health" | "/metrics")
+}
+
+fn is_fingerprinted_asset(path: &str) -> bool {
+    let Some(filename) = path.rsplit('/').next() else {
+        return false;
+    };
+    let Some((stem, extension)) = filename.rsplit_once('.') else {
+        return false;
+    };
+    if !matches!(extension, "css" | "js") {
+        return false;
+    }
+    let Some((_, hash)) = stem.rsplit_once('.') else {
+        return false;
+    };
+    hash.len() >= 8 && hash.bytes().all(|byte| byte.is_ascii_hexdigit())
+}
+
+fn is_static_asset_path(path: &str) -> bool {
+    path.rsplit('/')
+        .next()
+        .is_some_and(|segment| segment.contains('.'))
+}
+
+async fn static_cache_headers(
+    request: axum::extract::Request,
+    next: middleware::Next,
+) -> axum::response::Response {
+    let path = request.uri().path().to_string();
+    let mut response = next.run(request).await;
+
+    if is_api_path(&path) || response.headers().contains_key(header::CACHE_CONTROL) {
+        return response;
+    }
+
+    let cache_control = response
+        .headers()
+        .get(header::CONTENT_TYPE)
+        .and_then(|value| value.to_str().ok())
+        .filter(|content_type| content_type.contains("text/html"))
+        .map(|_| HeaderValue::from_static("no-cache, must-revalidate"))
+        .or_else(|| {
+            is_fingerprinted_asset(&path)
+                .then(|| HeaderValue::from_static("public, max-age=31536000, immutable"))
+        })
+        .or_else(|| {
+            is_static_asset_path(&path).then(|| HeaderValue::from_static("public, max-age=3600"))
+        });
+
+    if let Some(value) = cache_control {
+        response.headers_mut().insert(header::CACHE_CONTROL, value);
+    }
+
+    response
+}
+
 #[cfg(target_os = "linux")]
 fn resident_memory_kib() -> Option<u64> {
     let status = std::fs::read_to_string("/proc/self/status").ok()?;
@@ -558,6 +620,7 @@ async fn main() -> anyhow::Result<()> {
             }
         },
     ))
+    .layer(middleware::from_fn(static_cache_headers))
     .layer(cors)
     .layer(CompressionLayer::new().zstd(true).gzip(true))
     .layer(TraceLayer::new_for_http());