Public access of files over https seems to be broken with xrootd

[matthewfeickert]

In

https://github.com/iris-hep/uscms-idap-training/blob/437edaf5ef9cf961e047cadc16721d77d144e907/coffea/coffea-challenge-samplegame.ipynb

the following patch for people without access should have worked for @nsmith-'s example

prefix = 'https://xrootd-local.unl.edu:1094//store/user/AGC/samplegame/'
samples = [
    NanoEventsFactory.from_root(f"sample{i}.root").events()
    for i in range(6)
]

but is broken at the moment. The following hack around worked,

import os
_url = "https://xrootd-local.unl.edu:1094//store/user/AGC/samplegame"
[os.system(f"curl -sLO {_url}/sample{file_idx}.root") for file_idx in range(6)]

samples = [
    NanoEventsFactory.from_root(f"sample{i}.root").events()
    for i in range(6)
]

but this is not what should be done generally.

[lgray]

After talking with @oshadura we showed this fails with uproot alone as well.

So this may be an fsspec or uproot issue.

[matthewfeickert]

What uproot version? Though I see that @oshadura is writing an uproot Issue, so maybe she can link that here when she's done.

[oshadura]

scikit-hep/uproot5#1233