Fix #4546 (#4548)

* Refactor download

* emoji type

src/misc/detect-url-mine.ts

@@ -0,0 +1,15 @@
+import { createTemp } from './create-temp';
+import { downloadUrl } from './donwload-url';
+import { detectMine } from './detect-mine';
+
+export async function detectUrlMine(url: string) {
+	const [path, cleanup] = await createTemp();
+
+	try {
+		await downloadUrl(url, path);
+		const [type] = await detectMine(path);
+		return type;
+	} finally {
+		cleanup();
+	}
+}