Run HTML preview JavaScript in the desktop app

apps/desktop/src-tauri/src/main.rs

@@ -38,19 +38,26 @@ fn application_url(url: &tauri::Url) -> bool {
 
 fn preview_url(url: &tauri::Url) -> bool {
     // Embedded PDF/HTML previews use blobs minted by the application itself.
-    url.scheme() == "blob"
-        && tauri::Url::parse(url.path()).is_ok_and(|origin| application_url(&origin))
+    // HTML previews with JavaScript load the static oxbit-preview shell.
+    url.scheme() == "oxbit-preview"
+        || url.scheme() == "blob"
+            && tauri::Url::parse(url.path()).is_ok_and(|origin| application_url(&origin))
 }
 
 #[cfg(test)]
 mod preview_tests {
     use super::preview_url;
 
     #[test]
-    fn only_application_blob_urls_can_navigate() {
+    fn only_application_previews_can_navigate() {
         assert!(preview_url(
             &"blob:tauri://localhost/preview".parse().unwrap()
         ));
+        assert!(preview_url(
+            &"oxbit-preview://localhost/preview-shell.html"
+                .parse()
+                .unwrap()
+        ));
         for url in [
             "blob:https://example.com/preview",
             "blob:tauri://other/preview",

tests/desktop/workbench.e2e.mjs

@@ -215,6 +215,32 @@ describe("Oxbit native workbench", () => {
     assert.match(JSON.stringify(result.search), /hello.ts/);
     assert.equal(result.clipboard, "Oxbit native clipboard café");
   });
+  it("runs HTML preview JavaScript through the oxbit-preview shell in a trusted folder", async () => {
+    await browser.execute(async () => {
+      const { filesystem, runtime, workbench } = globalThis.__oxbit;
+      await runtime.trust(true);
+      addEventListener("message", (event) => {
+        if (event.data?.type === "native-preview-script")
+          globalThis.__nativePreviewScript = event.data.text;
+      });
+      await filesystem.write(
+        "preview.html",
+        '<!doctype html><h1 id="title">Static</h1><script>document.getElementById("title").textContent = "Script ran"; parent.postMessage({ type: "native-preview-script", text: document.getElementById("title").textContent }, "*");</script>',
+        { expectedRevision: null },
+      );
+      await workbench.openFile("preview.html", { preview: false });
+      await workbench.run("preview.html");
+    });
+    await browser.waitUntil(
+      () => browser.execute(() => globalThis.__nativePreviewScript),
+      { timeout: 20000, timeoutMsg: "The preview page's script did not run" },
+    );
+    assert.equal(
+      await browser.execute(() => globalThis.__nativePreviewScript),
+      "Script ran",
+    );
+    assert.equal(await $(".html-preview-scripts").isExisting(), false);
+  });
   it("completes TypeScript, cancels a real task, and stages a Git file in the native host", async () => {
     const completion = await browser.execute(async () => {
       const z = globalThis.__oxbit;