transfer: download 保存路径是目录时自动拼服务端文件名 (修复 IsADirectoryError); 测试 58 项

tests/test_transfer.py

@@ -231,6 +231,14 @@ class TestListDownload(TransferTestBase):
         self.assertEqual(got.read_bytes(), b"hello")
         got.unlink()
 
+    def test_download_to_dir(self):
+        # dest 是目录 -> 自动拼服务端文件名
+        dest_dir = self.tmp / "dl"
+        dest_dir.mkdir()
+        got = self.client.download("F-1", dest_dir)
+        self.assertEqual(got, dest_dir / "报告.pdf")
+        self.assertEqual(got.read_bytes(), b"hello")
+
     def test_download_unknown_404(self):
         with self.assertRaises(TransferError):
             self.client.download("NOPE")

transfer.py

@@ -119,19 +119,22 @@ class TransferClient:
         return payload.get("files", [])
 
     def download(self, file_id: str, dest: Path | None = None) -> Path:
-        """GET /api/files/{id}: 流式下载, 实时进度。dest 缺省用服务端文件名。"""
+        """GET /api/files/{id}: 流式下载, 实时进度。dest 缺省用服务端文件名; 是目录则拼文件名。"""
         req = urlrequest.Request(self.base_url + f"/api/files/{file_id}", method="GET")
         try:
             with urlrequest.urlopen(req, timeout=self.timeout) as resp:
+                # 从 Content-Disposition 取文件名 (filename*=utf-8''... 或 filename=...)
+                cd = resp.headers.get("Content-Disposition") or ""
+                name = "download.bin"
+                if "filename*=utf-8''" in cd:
+                    name = urlparse.unquote(cd.split("filename*=utf-8''")[1].split(";")[0])
+                elif "filename=" in cd:
+                    name = cd.split("filename=")[1].split(";")[0].strip('"')
                 if dest is None:
-                    # 从 Content-Disposition 取文件名 (filename*=utf-8''... 或 filename=...)
-                    cd = resp.headers.get("Content-Disposition") or ""
-                    name = "download.bin"
-                    if "filename*=utf-8''" in cd:
-                        name = urlparse.unquote(cd.split("filename*=utf-8''")[1].split(";")[0])
-                    elif "filename=" in cd:
-                        name = cd.split("filename=")[1].split(";")[0].strip('"')
                     dest = Path(name)
+                elif dest.is_dir():
+                    dest = dest / name
+                assert dest is not None
                 total = int(resp.headers.get("Content-Length") or 0)
                 done = 0
                 with open(dest, "wb") as f: