Cannot open ROOT over HTTPS

[jonas-eschle]

I cannot open a ROOT file over HTTPS with uproot4 while it works with uproot

import uproot4
_ = uproot4.open('https://cern.ch/starterkit/data/advanced-python-2019/dalitzdata.root')

It fails with

OSError: remote server does not support HTTP range requests
for URL https://cern.ch/starterkit/data/advanced-python-2019/dalitzdata.root

Do you have any ideas what may goes wrong?

Full StackTrace:

OSError                                   Traceback (most recent call last)
<ipython-input-3-2fc8249c41b5> in <module>
----> 1 _ = uproot4.open('https://cern.ch/starterkit/data/advanced-python-2019/dalitzdata.root')

~/anaconda3/envs/starterkit38/lib/python3.8/site-packages/uproot4/reading.py in open(path, object_cache, array_cache, custom_classes, **options)
    134         )
    135 
--> 136     file = ReadOnlyFile(
    137         file_path,
    138         object_cache=object_cache,

~/anaconda3/envs/starterkit38/lib/python3.8/site-packages/uproot4/reading.py in __init__(self, file_path, object_cache, array_cache, custom_classes, **options)
    565             self._fUUID_version,
    566             self._fUUID,
--> 567         ) = uproot4.source.cursor.Cursor(0).fields(
    568             self._begin_chunk, _file_header_fields_small, {}
    569         )

~/anaconda3/envs/starterkit38/lib/python3.8/site-packages/uproot4/source/cursor.py in fields(self, chunk, format, context, move)
    193         if move:
    194             self._index = stop
--> 195         return format.unpack(chunk.get(start, stop, self, context))
    196 
    197     def field(self, chunk, format, context, move=True):

~/anaconda3/envs/starterkit38/lib/python3.8/site-packages/uproot4/source/chunk.py in get(self, start, stop, cursor, context)
    360         already.
    361         """
--> 362         self.wait()
    363 
    364         if (start, stop) in self:

~/anaconda3/envs/starterkit38/lib/python3.8/site-packages/uproot4/source/chunk.py in wait(self)
    314         """
    315         if self._raw_data is None:
--> 316             self._raw_data = numpy.frombuffer(self._future.result(), dtype=self._dtype)
    317             if len(self._raw_data) != self._stop - self._start:
    318                 raise OSError(

~/anaconda3/envs/starterkit38/lib/python3.8/site-packages/uproot4/source/futures.py in result(self, timeout)
    124             return self._result
    125         else:
--> 126             delayed_raise(*self._excinfo)
    127 
    128     def _run(self):

~/anaconda3/envs/starterkit38/lib/python3.8/site-packages/uproot4/source/futures.py in delayed_raise(exception_class, exception_value, traceback)
     44         exec("raise exception_class, exception_value, traceback")
     45     else:
---> 46         raise exception_value.with_traceback(traceback)
     47 
     48 

~/anaconda3/envs/starterkit38/lib/python3.8/site-packages/uproot4/source/futures.py in _run(self, resource)
    281     def _run(self, resource):
    282         try:
--> 283             self._result = self._task(resource)
    284         except Exception:
    285             self._excinfo = sys.exc_info()

~/anaconda3/envs/starterkit38/lib/python3.8/site-packages/uproot4/source/http.py in task(resource)
    199 
    200         def task(resource):
--> 201             return resource.get(connection, start, stop)
    202 
    203         return uproot4.source.futures.ResourceFuture(task)

~/anaconda3/envs/starterkit38/lib/python3.8/site-packages/uproot4/source/http.py in get(self, connection, start, stop)
    167         if response.status != 206:
    168             connection.close()
--> 169             raise OSError(
    170                 """remote server does not support HTTP range requests
    171 for URL {0}""".format(

OSError: remote server does not support HTTP range requests
for URL https://cern.ch/starterkit/data/advanced-python-2019/dalitzdata.root

[jpivarski]

I haven't tested it, but this might be related to #121.

[jonas-eschle]

In fact, you're right! Thanks! closing
Update: sorry, not quite

[jonas-eschle]

Actually, the opening works, but then it fails again (while working for uproot)

command:
uproot4.open('https://starterkit.web.cern.ch/starterkit/data/advanced-python-2019/dalitzdata.root')['tree'].arrays()

Error:

OSError: found 0 of 156 expected headers in HTTP multipart
for URL https://starterkit.web.cern.ch/starterkit/data/advanced-python-2019/dalitzdata.root

[chrisburr]

It looks like something with multipart HTTP requests was broken between v0.0.17 and v0.0.20

[jonas-eschle]

Reopened, as it seems to me that this was not entirely fixed. The snippet above still errors:
Actually, the opening works, but then it fails again (while working for uproot)

file = uproot4.open('https://starterkit.web.cern.ch/starterkit/data/advanced-python-2019/dalitzdata.root')
_ = file['tree'].arrays()  # fails here

It fails "later" though than the fix I assume, so I've rearranged the example.

Error:

OSError: found 0 of 156 expected headers in HTTP multipart
for URL https://starterkit.web.cern.ch/starterkit/data/advanced-python-2019/dalitzdata.root

[jpivarski]

Darn: the test only checked

data = f["tree/Y1"].array()

which works. I'm looking into the issue with multiple branches.