Creating new files with custom ContentsManager

#1

Hello.

I’m writing a custom ContentsManager manager for Jupyter Notebooks and gotten to creating new files.

Originally my file_exists function always returned True and I’ve gotten Cannot POST to files, use PUT instead error, same as this issue.

Following that I amended file_exists function to return False, however now Jupyter is stuck in the loop calling file_exists with:

/dir
/dir/Untitled.ipynb
/dir/Untitled1.ipynb
/dir/Untitled2.ipynb
...

My question is - what should I return from file_exists so that notebook creation goes along?

I though maybe get or save get called after file_exists but that doesn’t seem to be the case.

#2

Is your file_exists method always returning a fixed value? What happens if you change it so it returns True if the file exists and False if it doesn’t?

#3

Originally, yes, but now I’m just trying to understand what it must return so file creation goes along.

I thought so at first, but Jupyter seems to check file_exists once per file.
The sequence seem not to be:

check if file exist
do something
check if file exist again

But rather:

check if file exist
check if file2 exist
....

So I don’t understand what must I answer on a first file_exist.

#4

I recently wrote my own ContentsManager and the file_exists method is implemented as you’d expect. Is your code visible in a public repository?

#6

Notebook creation fails through. I think notebook creation happens here and it seems like file_exists should always return true and dir_exists should always return false yet this configuration causes infinite loop described above.

#7

What are you using for your Checkpoints? When I wrote my ContentsManager I also needed to write a Checkpoints class before saving notebooks would work properly.

#8

Ooh, I’m not using checkpoints for now. Is it a requirement?

I’ll write a small checkpoints wrapper and see if it helps.

Thanks for the idea.

Docs don’t specify that checkpoints class is required,so I thought they are optional.

#9

I’m not sure if it’s strictly required, it might be possible to disable it but I couldn’t figure out how so ended up writing my own.

#10

@manics checkpoints don’t matter, but thank you for the advice. Here’s the answer:
exist - false
exist_dir for dir - true
exist_dir for file - false
That’s the ticket

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