feat(axum): expose hashed runtime asset path

Generate a SHA-256 content hash for the embedded hemx runtime, expose the hashed path from hemx-axum, serve immutable runtime headers, and update examples to load the hemx-owned path instead of fixed /hemx.js URLs.

req: axum_integration/005

hemx-axum/src/lib.rs

@@ -27,6 +27,16 @@ pub const fn runtime_js() -> RuntimeJs {
     RuntimeJs
 }
 
+// req: axum_integration/005
+pub const fn runtime_js_hash() -> &'static str {
+    hemx_js::RUNTIME_JS_HASH
+}
+
+// req: axum_integration/005
+pub const fn runtime_js_path() -> &'static str {
+    hemx_js::RUNTIME_JS_PATH
+}
+
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub enum PageMode {
     Full,
@@ -1382,6 +1392,16 @@ impl IntoResponse for RuntimeJs {
             header::CACHE_CONTROL,
             HeaderValue::from_static("public, max-age=31536000, immutable"),
         );
+        response.headers_mut().insert(
+            header::ETAG,
+            HeaderValue::from_str(&format!("\"{}\"", runtime_js_hash()))
+                .expect("runtime hash is a valid ETag"),
+        );
+        response.headers_mut().insert(
+            header::CONTENT_LENGTH,
+            HeaderValue::from_str(hemx_js::RUNTIME_JS.len().to_string().as_str())
+                .expect("runtime length is a valid header value"),
+        );
         response
     }
 }
@@ -1390,6 +1410,14 @@ pub fn runtime_js_source() -> &'static str {
     hemx_js::RUNTIME_JS
 }
 
+pub fn runtime_js_script_src() -> &'static str {
+    runtime_js_path()
+}
+
+pub fn runtime_js_route_path() -> &'static str {
+    runtime_js_path()
+}
+
 // req: push/001, req: push/003, req: push/004
 pub fn sse<S, E>(batches: S) -> Sse<impl Stream<Item = Result<Event, E>> + Send>
 where

hemx-axum/tests/response.rs

@@ -2,9 +2,10 @@ use axum::extract::State;
 use axum::http::{header, HeaderMap};
 use axum::response::IntoResponse;
 use hemx_axum::{
-    interactions, runtime_js, DispatchRejection, EffectResponse, Form, HandlerErrorContext,
-    HandlerFailure, InteractionForm, InteractionFormRejection, InteractionRequest,
-    IntoHandlerFailure, PageMode, PageRequest, PageResponse, HEMX_CONTENT_TYPE,
+    interactions, runtime_js, runtime_js_hash, runtime_js_path, runtime_js_route_path,
+    runtime_js_script_src, runtime_js_source, DispatchRejection, EffectResponse, Form,
+    HandlerErrorContext, HandlerFailure, InteractionForm, InteractionFormRejection,
+    InteractionRequest, IntoHandlerFailure, PageMode, PageRequest, PageResponse, HEMX_CONTENT_TYPE,
     HEMX_FINGERPRINT_HEADER, HEMX_PARTIAL_HEADER, HEMX_RUNTIME_CONTENT_TYPE, HEMX_TITLE_HEADER,
 };
 use hemx_core::{push, BuildFingerprint, Handle, IntoEffect, SafeHtml, Slot};
@@ -480,5 +481,29 @@ fn runtime_js_response_serves_embedded_runtime() {
         response.headers()[header::CONTENT_TYPE],
         HEMX_RUNTIME_CONTENT_TYPE
     );
-    assert!(response.headers().contains_key(header::CACHE_CONTROL));
+    assert_eq!(
+        response.headers()[header::CACHE_CONTROL],
+        "public, max-age=31536000, immutable"
+    );
+    assert_eq!(
+        response.headers()[header::ETAG],
+        format!("\"{}\"", runtime_js_hash())
+    );
+    assert_eq!(
+        response.headers()[header::CONTENT_LENGTH],
+        runtime_js_source().len().to_string()
+    );
+}
+
+// req: axum_integration/005
+#[test]
+fn runtime_js_path_is_content_hashed() {
+    let path = runtime_js_path();
+
+    assert!(path.starts_with("/hemx."));
+    assert!(path.ends_with(".js"));
+    assert!(path.contains(runtime_js_hash()));
+    assert_eq!(runtime_js_script_src(), path);
+    assert_eq!(runtime_js_route_path(), path);
+    assert_eq!(runtime_js_hash().len(), 64);
 }