Parse question and answer from cell metadata

[psychemedia]

When authoring a self-contained notebook for rendering as a Jupyter Book, it's presumably easy enough to put question and answer definitions into a removed code cell in the final book output.

However, if the notebook is used as a notebook, the answers are evident in the code cell.

In such a case, it might be useful to pop the question and answer dictionary into the cell metadata as a JSON object and then render that into the multiple choice widget?

It's a bit of a faff for the notebook author having to edit the metadata cell, but it would keep the notebook self-contained and the answer source hidden to some extent.

[jmshea]

Shouldn't be too hard to implement. I will look into implementing this soon

[jmshea]

Actually, I can't see how to access cell metadata either from Python or from Javascript. It does not seem to be added to the DOM, for instance. Let me know if you have any ideas.

As a less attractive workaround, I could add an option to take in the data as Base64-encoded JSON, which is easy to create but not human readable. Let me know what you think.

[psychemedia]

Yes, I'd suddenly started wondering too about how the introspection would work. It's easy enough to access cell metadata from eg a notebook extension, but that is changing the scope a bit.

From a quick search around, there's a recipe at https://habr.com/en/post/439570/ that shows how to set cell tags using magic, so presumably a complementary approach along the lines of q_and_a = %get_metadata qna to get a cell.metadata.qna object might work?

[psychemedia]

Hmmm... I wonder if that js / magic approach might be limited where it works. Eg would it work in a notebook edited / run in VS Code?

[psychemedia]

Okay, so this is very hacky and riffs on https://habr.com/en/post/439570/ with added an IPython.notebook.kernel.execute() Javascript function call. It may also only work in classic notebook UI (I still haven't migrated away from that!)

In a code cell, run:

%%javascript
define('getCellMetadata', function() {
    return function(element) {
        var cell_element = element.parents('.cell');
        var index = Jupyter.notebook.get_cell_elements().index(cell_element);
        var cell = Jupyter.notebook.get_cell(index);
        var jsonString = JSON.stringify(cell.metadata);
        IPython.notebook.kernel.execute("cell_metadata = '"+jsonString+"'");
    }
});

Alternatively, that can probably just be wrapped in Python code, eg as:

display(Javascript("""
define('getCellMetadata', function() {
    return function(element) {
        var cell_element = element.parents('.cell');
        var index = Jupyter.notebook.get_cell_elements().index(cell_element);
        var cell = Jupyter.notebook.get_cell(index);
        var jsonString = JSON.stringify(cell.metadata);
        IPython.notebook.kernel.execute("my_out = '"+jsonString+"'");
    }
});
"""))

Then define some magic:

def _get_metadata(key):
    display(Javascript(
        """
        require(['getCellMetadata'], function(getCellMetadata) {
            getCellMetadata(element);
        });
        """
    ))


@register_line_cell_magic
def get_metadata(line, cell=None):
    _get_metadata(line)

Then in a code cell that has metadata attached, run the magic:

%get_metadata

Then in another code cell you can reference the stringified metadata:

cell_metadata

I think this needs to be accessed in a cell separate to line magic cell because of the async way in which things get executed?

[jmshea]

"Jupyter" isn't even defined in JupyterLab. I can't find anything equivalent, and I listed out all the local objects in JS.

[psychemedia]

Ah... I still haven't moved to JuptyerLab/RetroLab: too complicated for me. I'm pretty much locked into classic notebook.

[psychemedia]

Possibly related:

• How to update notebook metadata on jupyterlab using javascript? (JupyterLab issue, closed and unresolved)
• Feature suggestion: visually distinguish (color) cells with a tag(JupyterLab issue; stalled?)
• Jupyter Enhancement Project: Pre-Proposal: Transmit Cell Metadata
• Jupyter Enhancement Project: Proposal: Transmit Cell Metadata

[psychemedia]

If you write an extension, then you can get access to cell metadata (for example, the JupyterLab Collapsible_Headings extension uses cell metadata to identify header cells marked as collapsed).

A more elaborate way of making use of an extension might be an extension that supports authoring of example answer tests, cf. cell tests as per the nbcelltests JupyterLab extension. The problem then becomes one of how to disable that view to students whilst still supporting the self-test/formative grading when the cell is run.

[jmshea]

TLDR: I plan to close this issue after adding base64 encoding. Using this plus Collapse Selected Code in JupyterLab seems a good compromise in terms of implementing the behavior you want.

An extension is out of my expertise and interest on this project. I have put some time into trying to find a way to access the cell metadata from either cell JavaScript or Python, and unfortunately I haven't figured out how it can be done in JupyterLab. If you have any knowledge about how to do that, let me know.

I will go ahead and add the ability to read in the questions as base64-encoded stringified JSON as a stopgap. In JupyterLab, you can then set the cell containing that to be "hidden" in JupyterLab via View-> Collapse Selected Code. It can be "uncollapsed", but the questions/answers won't be human readable. I don't know if Collapse carries over to Jupyter notebook. I did some experiments at trying to auto-hide things using JS, but basically all that hiding would go away when the document was reloaded, unless the JS cell was explicitly run.

[psychemedia]

Okay, thanks for exploring this too. I think that there are various discussions around extending the notebook format, as well as proposals regarding the propagation of metadata to kernels in JupyterLab, but actually contributing to those is outside my skillset; I will however maintain a watching brief over them until such a time as they become available and can be easily coopted for use...

[jmshea]

I think I have implemented nearly equivalent behavior to satisfy this request. You can now store a question as either JSON or base64-encoded JSON in a hidden HTML element within a Markdown cell. Then you can show that question using JupyterQuiz by passing the ID of the HTML element.

This works in both Jupyter Notebook and Jupyter Lab.

Please see the notebook HideQuiz.ipynb for examples.

I will update the README.md later to document this feature.

I hope that you find this helpful!