provide user-agent

Author: rok

python/pyarrow/util.py

@@ -231,8 +231,9 @@ def _break_traceback_cycle_from_frame(frame):
 
 
 def _download_urllib(url, out_path):
-    from urllib.request import urlopen
-    with urlopen(url) as response:
+    from urllib.request import urlopen, Request
+    req = Request(url, headers={'User-Agent': 'pyarrow'})
+    with urlopen(req) as response:
         with open(out_path, 'wb') as f:
             f.write(response.read())