Unable to retrieve the filename of FileInput widget in the callback function but only after

[philippine56]

Hello everyone!

I am relatively new to Bokeh but starting to get around a bit better.
I have a relatively long file that first ask to updload some csv files and then the data in the files is filtered and plotted in 4 graphs.
I would like to give the the filename of the csv to the file when uploaded with the FileInput widget. But for some reason, I can only retrieve the name after I click on the button “upload data” and not directly in the callback function of the FileInput widget.
Here is the simplified code with only one button.

series = []


def upload_data1(attr, old, new):  # there are several fileinput widgets
    print('file uploaded successfully...')
    decoded = b64decode(new)
    f = io.BytesIO(decoded)
    data1 = pd.read_csv(f, sep=';')
    data1 = data1.loc[:, ~data1.columns.str.contains('^Unnamed')]
    series.append(data1)
    print('file_input1.filename 1 :', file_input1.filename)


def load_data():
    print('file_input1.filename 2:', file_input1.filename)
    columns = sorted(series[0].columns)  # every set of data uploaded has the same columns
    plotting(series, columns)  # function that creates new widgets and plots graphs with all the data in series


# File input
file_input1 = FileInput(accept=".csv", width=250)
file_input1.on_change('value', upload_data1)

bt = Button(label="Load data", width=150)
bt.on_click(load_data)

data_set = row([file_input1, bt])
curdoc().add_root(data_set)
show(data_set)


def plotting(series, columns):
    pass

I then call my code with bokeh serve --websocket-max-message-size 100000000 github.py

As you can see, I can only access the filename in the function load_data:

Is there a way to get in the callback function ?
Thank you for your help

[Bryan]

This is an open issue:

[FEATURE] where there are multiple related properties that might need to be responded to as a group, respond to them only after all are guaranteed to be updated · Issue #11461 · bokeh/bokeh · GitHub

You might have better luck adding a callback on the filename property as it seems it updated after the value property, so should be able to access both at that point.

[philippine56]

Great, thank you very much. It works perfectly now!