plotly.io.to_json method does not convert large numbers correctly

[jimholl-dev]

Hi, I have some some code here, as below (edited to remove extra logs). I'm converting a plotly figure into json, and then loading it with json loads. You would expect that to preserve the original data.

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However, as you can see, the "y" data (which had previously been an array of large numbers) are wrongly converted into this "bdata" thing instead.

I was able to solve this and get the data in the format I wanted by going from 6.0.1 -> 5.24.1, which was the last stable build I was using. I think this is a pretty fundamental issue, so let me know if there's anything else I can share.

[miraculixx]

This may not solve your issue, however I had a similar issue in a client application, rendering the json object using the plotly.js library.

It turned out I was using an outdated plotly javascript library, which in versions prior to v2.28 did not know about bdata (base64 encoded). Once I upgraded to the latest version of plotly.js it worked fine.

[gvwilson]

@marthacryan suggests adding a base64: bool argument to plotly.io.to_json (similar to pretty: bool) that would control whether data is base64'd or not.

[marthacryan]

For some context on implementation: the BaseFigure class does the conversion to base64 in the to_dict function here: https://github.com/plotly/plotly.py/blob/1ec864bbed58ee2834a879d323ade4b53bfde364/plotly/basedatatypes.py#L3344. So this is the call stack:

1. to_json calls validate_coerce_fig_to_dict here
2. validate_coerce_fig_to_dict calls BaseFigure.to_dict here.

So, we'd have to add a flag to plotly.io.to_json and validate_coerce_fig_to_dict and BaseFigure.to_dict.