Reading the Value Attribute of a Checkbox in Flask/WTF

user_5508736 0
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I have a form with a column of checkboxes corresponding to the columns in my database. I'm setting the value of each checkbox (in javascript) to the name of the column, but when I try to read the checkbox value in Flask/Python all I can get is True or False. How do I read the text value of the value attribute of the checkboxes?

Just to complicate things, I'm generating the form as a FieldList of FormFields, so I can't simply hardcode the field names. (Well, I could, but that would make it fragile to schema changes.)

My form code is

class ImportFilterSubForm(Form):
    use = BooleanField(
        'Use', 
        render_kw={'class': 'use'}
    )
    sel = SelectField(
        'Maps to:', 
        choices=[], 
        render_kw={'class': 'sel'}, 
        validators=[Optional()]
    )

class ImportFilterForm(FlaskForm):
    rows = FieldList(FormField(ImportFilterSubForm))

My view code, with error handling removed, is

def prefilter_import():
    db_columns = Contact.__table__.columns.keys()
    filename = request.cookies.get('workfile')
    with open(filename) as fh:
        reader = csv.DictReader(fh)
        file_columns = reader.fieldnames
    
    form = ImportFilterForm()
    for col in db_columns:
        new_row = form.rows.append_entry()
        new_row.use.label = col
        new_row.sel.choices = file_columns
    
    input_file = request.cookies.get('input_file')
    return render_template('filter_import.html', form=form, filename=input_file)

def postfilter_import():
    form = ImportFilterForm()

    db_columns = Contact.__table__.columns.keys()
    filename = request.cookies.get('workfile')
    with open(filename) as fh:
        reader = csv.DictReader(fh)
        file_columns = reader.fieldnames
    
    missing_columns = db_columns
    extra_columns = file_columns
    
    mappings = dict()
    for i, row in enumerate(form.rows):
        if row.use.data:  # Problem arises here
            mappings[row.use.data] = row.sel.data
    
    for key, value in mappings.items():
        missing_columns.remove(key)  # Problem manifests here
        extra_columns.remove(value)

I'm trying to create a dict mapping the values of the checkboxes to the values of the selects, but I'm only getting True and False for the checkboxes, even though I've verified that the checkboxes' value attributes are correctly returned as the names of the corresponding columns.

How can I get Flask/WTForms to return the text of the value attributes?

wtforms flask-wtforms flask forms python
1 Answers

After some investigation, I discovered the raw_data attribute of the field object, which contains a list of the values of the value attributes of the HTML control. Thus, the code

    mappings = dict()
    for row in form.rows:
        if row.use.data:
            mappings[row.sel.data] = row.use.raw_data[0]
    
    for key, value in mappings.items():
        missing_columns.remove(value)
        extra_columns.remove(key)

does what I need it to do.

user_55087360
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