notebook=6.1.3 download files with spaces gives a 404

[AbdealiLoKo]

I was earlier using notebook==6.0.3 and have recently shifted to notebook==6.1.3.
I find that with the newer version, when I try to download files with spaces - it fails witha 404 error.

I run jupyter notebook with jupyter notebook. No special configs have been set.

When I create a file called my file.ipynb and:

• Download (gives 404): http://localhost:8888/files/my%2520file.ipynb?download=1
• View (works fine): http://localhost:8888/notebooks/my%20file.ipynb

In jupyter 6.0.3 - When I create a file called my file.ipynb and:

• Download (works fine): http://localhost:8888/files/my%20file.ipynb?download=1
• View (works fine): http://localhost:8888/notebooks/my%20file.ipynb

It looks like when we download a file with spaces in it - the URL is different now (it has a extra %25 in it)

The same issue occurs if the folder has spaces instead of the file

NOTE: When I try this on try-jupyter https://jupyter.org/try it works fine - It seems to be using 6.0.3

[kevin-bates]

😞 Looks like this update is leading to a double-encoding: <sp> -> %20 -> %2520

cc: @berendjan @Zsailer

[Zsailer]

Thanks for raising this issue, @AbdealiJK.

Indeed—there's a double encoding happening. Fixed in #5720