feat(core): fallback to {path}.html in Tauri protocol loader ref #3887

 (#3939)

.changes/asset-default-ext-fallback.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch
+---
+
+Fallback to `{path}.html` when `{path}` is not found in the Tauri custom protocol handler.

core/tauri/src/manager.rs

@@ -751,14 +751,26 @@ impl<R: Runtime> WindowManager<R> {
     let asset_response = assets
       .get(&path.as_str().into())
       .or_else(|| {
+        eprintln!("Asset `{}` not found; fallback to {}.html", path, path);
+        let fallback = format!("{}.html", path.as_str()).into();
+        let asset = assets.get(&fallback);
+        asset_path = fallback;
+        asset
+      })
+      .or_else(|| {
+        #[cfg(debug_assertions)]
+        eprintln!(
+          "Asset `{}` not found; fallback to {}/index.html",
+          path, path
+        );
         let fallback = format!("{}/index.html", path.as_str()).into();
         let asset = assets.get(&fallback);
         asset_path = fallback;
         asset
       })
       .or_else(|| {
         #[cfg(debug_assertions)]
-        eprintln!("Asset `{}` not found; fallback to index.html", path); // TODO log::error!
+        eprintln!("Asset `{}` not found; fallback to index.html", path);
         let fallback = AssetKey::from("index.html");
         let asset = assets.get(&fallback);
         asset_path = fallback;