Refactor zero sized file downloading (modelscope#991)

modelscope/hub/file_download.py

@@ -461,17 +461,23 @@ def http_get_model_file(
                 unit='B',
                 unit_scale=True,
                 unit_divisor=1024,
-                total=file_size,
+                total=file_size if file_size > 0 else 1,
                 initial=0,
                 desc='Downloading [' + file_name + ']',
             )
+            if file_size == 0:
+                # Avoid empty file server request
+                with open(temp_file_path, 'w+'):
+                    progress.update(1)
+                    progress.close()
+                    break
             partial_length = 0
             if os.path.exists(
                     temp_file_path):  # download partial, continue download
                 with open(temp_file_path, 'rb') as f:
                     partial_length = f.seek(0, io.SEEK_END)
                     progress.update(partial_length)
-            if partial_length >= file_size > 0:
+            if partial_length >= file_size:
                 break
             # closed range[], from 0.
             get_headers['Range'] = 'bytes=%s-%s' % (partial_length,

tests/hub/test_hub_empty_file.py

@@ -0,0 +1,31 @@
+# Copyright (c) Alibaba, Inc. and its affiliates.
+import os.path
+import shutil
+import tempfile
+import unittest
+
+from modelscope import snapshot_download
+
+
+class HubEmptyFile(unittest.TestCase):
+
+    def setUp(self):
+        temporary_dir = tempfile.mkdtemp()
+        self.work_dir = temporary_dir
+
+    def tearDown(self):
+        shutil.rmtree(self.work_dir, ignore_errors=True)
+
+    def test_download_empty_file(self):
+        model_dir = snapshot_download(
+            'tastelikefeet/test_empty_download', cache_dir=self.work_dir)
+        self.assertTrue(model_dir is not None)
+        self.assertTrue(os.path.exists(os.path.join(model_dir, '1.txt')))
+        self.assertTrue(
+            os.path.exists(os.path.join(model_dir, 'configuration.json')))
+        self.assertTrue(os.path.exists(os.path.join(model_dir, 'init.py')))
+        self.assertTrue(os.path.exists(os.path.join(model_dir, 'README.md')))
+
+
+if __name__ == '__main__':
+    unittest.main()