merge: v2/1560-downloadfile (#1586)

clients/web/src/lib/downloadFile.ts

@@ -2,22 +2,23 @@
  * Browser-side helpers for triggering file downloads from in-memory content.
  *
  * Centralized so the temp-anchor incantation (`appendChild` for Firefox,
- * try/finally to keep cleanup bulletproof, `revokeObjectURL` to release the
- * object URL) lives in one place — and so the wiring is unit-testable
- * under happy-dom without dragging React along.
+ * deferred `revokeObjectURL` so the scheduled download can read the blob)
+ * lives in one place — and so the wiring is unit-testable under happy-dom
+ * without dragging React along.
  */
 
 /**
- * Download an in-memory string as a JSON file. Uses a temporary anchor
+ * Download an in-memory {@link Blob} as `filename`. Uses a temporary anchor
  * element to trigger the browser's save dialog. The append-to-body step is
  * for older Firefox versions that wouldn't fire `click()` on a detached
  * anchor; modern browsers don't require it but it stays as the safe path.
  *
- * The cleanup (removeChild + revokeObjectURL) runs in a `finally` so even
- * a thrown `click()` doesn't leak the DOM node or the object URL.
+ * The object-URL revoke is deferred to a task: `link.click()` only schedules
+ * the download, and revoking the URL synchronously can abort it before the
+ * browser reads the blob (Firefox/Safari, intermittently Chrome for larger
+ * blobs).
  */
-export function downloadJsonFile(filename: string, json: string): void {
-  const blob = new Blob([json], { type: "application/json" });
+export function downloadBlob(filename: string, blob: Blob): void {
   const url = URL.createObjectURL(blob);
   const anchor = document.createElement("a");
   anchor.href = url;
@@ -27,7 +28,43 @@ export function downloadJsonFile(filename: string, json: string): void {
     anchor.click();
   } finally {
     document.body.removeChild(anchor);
-    URL.revokeObjectURL(url);
+    setTimeout(() => URL.revokeObjectURL(url), 0);
+  }
+}
+
+/** Download an in-memory JSON string as `filename`. */
+export function downloadJsonFile(filename: string, json: string): void {
+  downloadBlob(filename, new Blob([json], { type: "application/json" }));
+}
+
+/**
+ * Derive a safe suggested filename from a resource URI: the last path segment,
+ * stripped of control/format characters, path separators, and characters
+ * disallowed in filenames on common platforms. Falls back to `"download"` when
+ * nothing usable remains.
+ */
+export function fileNameFromUri(uri: string): string {
+  const tail = uri.split(/[\\/]/).pop() ?? "";
+  const safe = tail
+    .replace(/[\p{Cc}\p{Cf}]+/gu, "")
+    .replace(/[\\/:*?"<>|]+/g, "_")
+    .trim();
+  return safe.length > 0 ? safe.slice(0, 255) : "download";
+}
+
+/**
+ * Parse `url` and return it only if its scheme is `http:` or `https:`;
+ * otherwise null. Shared http(s)-only allowlist for opening or downloading
+ * server-supplied URLs.
+ */
+export function isHttpUrl(url: string): URL | null {
+  try {
+    const parsed = new URL(url);
+    return parsed.protocol === "https:" || parsed.protocol === "http:"
+      ? parsed
+      : null;
+  } catch {
+    return null;
   }
 }