form works, but form.is_valid() returns false

Using Django Forms & APIs
1

I am working on a form that takes two dates and then fetches all the database rows whose timestamp value is between the begin and end dates.

class DateForm(forms.Form):
    """Form for the date fields in which the user can see which month is
    currently selected, and also change it.
    """
    begin_date = forms.DateField(
        label='Begin Date',
        widget=forms.SelectDateWidget(years=range(1990, 2040))
    )

    end_date = forms.DateField(
        label='End Date',
        widget=forms.SelectDateWidget(years=range(1990, 2040))
    )

    def clean(self):
        cleaned_data = super().clean()
        begin_date = cleaned_data.get('begin_date')
        end_date = cleaned_data.get('end_date')

        # Check if begin_date is less than end_date
        if begin_date and end_date and begin_date >= end_date:
            cleaned_data['begin_date'], cleaned_data['end_date'] = end_date, begin_date

        return cleaned_data

In my def show(request, process_name, begin_date=False, end_date=False) function I call the form like this:

initial_data = {'begin_date': begin_date,
                        'end_date': end_date}
date_form = DateForm(initial=initial_data)

where begin_date and end_date are valid string objects.

But when I call date_form.is_valid(), it returns false:

I tried printing all errors using date_form.errors.as_data() and date_form.errors, but I only got an empty dictionary.

I also tried converting begin_date and end_date to datetime.datetime, but it does not change anything.

When I use the form to get the rows within the specific dates, it does work. What’s going on here?

2

Please post the view where you are doing this work.

3

Hi, here is the show function:

def show(request, p_name, begin_date=False, end_date=False):
    pc = get_all_models()[p_name]
    p_name = "test"
    namespace = pc._meta.app_label

    initial_data = {'begin_date': begin_date,
                    'end_date': end_date}
    date_form = DateForm(initial=initial_data)
    
    template = loader.get_template("samples/xxx_" + process_name + ".html")
    template_context = RequestContext(request, pc.get_xxx_context_range(begin_date, end_date))
    template_context["request"] = request
    html_body = template.render(template_context.flatten())
    try:
        if date_form.is_valid():
            export_url = django.urls.reverse(
                "{}:export_xxx_{}".format(namespace, p_name),
                kwargs={'begin_date': datetime.strptime(begin_date, "%Y-%m-%d"),
                        'end_date': datetime.strptime(end_date, "%Y-%m-%d")}) + "?next=" + quote_plus(request.path)
    except django.urls.NoReverseMatch:
        export_url = None
    return render(request, "samples/xxx.html",
                  {
                   "html_body": html_body, 
                   "export_url": export_url})
4

You’re creating an unbound form with initial values, you’re not “binding” the data to the forms as if it were being submitted. The is_valid function is always going to be false for unbound forms.

Read the docs (and the examples) at Bound and unbound forms.