# Informing user of callback exceptions

**URL:** https://community.plotly.com/t/informing-user-of-callback-exceptions/7870
**Category:** Dash Python
**Created:** [January 22, 2018, 12:19pm UTC](https://community.plotly.com/t/informing-user-of-callback-exceptions/7870 "2018-01-22T12:19:52Z")
**Posts on this page:** 1
**Showing post:** 4

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### Author: ![mkhorton](https://sea2.discourse-cdn.com/flex024/user_avatar/community.plotly.com/mkhorton/32/2260_2.png) [@mkhorton](https://community.plotly.com/u/mkhorton)
#### Post date: [May 8, 2018, 12:22am UTC](https://community.plotly.com/t/informing-user-of-callback-exceptions/7870/4 "2018-05-08T00:22:27Z")

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I’m wondering about this as well … I have some callbacks that will fail in some cases, and I’d like to display a warning to the user when they do.

I can imagine a few hack-ish ways of doing this, storing state in hidden divs, some try/excepts, etc., but this seems a bit clunky for production.

What I’d really like something like the solution proposed in [Improving handling of aborted callbacks](https://community.plotly.com/t/improving-handling-of-aborted-callbacks/7536) but with an addition like:

```auto
@app.handle_callback_errors(Output('my-user-warning-div', 'value'), [my_callback_func])
def handle_error(error):
    # whenever a callback (e.g. my_callback_func) raises a PreventUpdate exception, the exception
    # is passed to this handle_error function, which is itself a callback and can display a warning to the user

```

Would something like this be possible within the design of Dash?

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