Exiting a callback

[shoppar]

Out of curiosity is there a protocol for exiting a callback without triggering any other callbacks chained to the current one?

For example if there is no new data and you want to skip the callbacks that refresh your plots.

Thanks

[rad]

This thread seems to be very similar to what you’re trying to work on

Avoid running callback if inputs are the same

I was’t sure what to title this… in my app, I have some API calls which I’d like to minimize for financial implications. The user will have some text boxes to type into, I take those contents and some other options, build an API call and make the request. Currently, I’m using a button as an Input and the dcc.Input boxes are passed via State to avoid the callback trying to fire with every changed character. I’d like to figure out how to only run the API call for changed elements when the button …

[chriddyp]

@shoppar

Out of curiosity is there a protocol for exiting a callback without triggering any other callbacks chained to the current one?

You can raise an exception inside your function.

Here’s where this happens in the code: Any non-200 level will then be ignored by dash’s front-end: dash-renderer/src/actions/index.js at 9992d73303492671d9619c161b9184d35f43faf6 · plotly/dash-renderer · GitHub

[shoppar]

Thanks @rad - I think that thread’s more concerning cacheing callbacks than exiting though.

[shoppar]

Thank you @chriddyp that looks like it could be the best solution

[klnrdknt]

Follow up question: Does this have to be a specific error or any kind? And I just invoke one within the callback function?

[chriddyp]

@klnrdknt

Does this have to be a specific error or any kind? And I just invoke one within the callback function?

Any uncaught exception will work. We recommend the dash.exceptions.PreventUpdate() exception, see here: Improving handling of aborted callbacks - #2 by chriddyp

[klnrdknt]

Superb, thank you very much.