Django manipulate / modify date in template - django

Question

Is it possible to make an input that changes the date.today for the whole template ?
my template
{% for Ansicht in Ansicht.lehrertabelle_set.all %}
<tbody>
<tr>
<th scope="row"></th>
<td>{{Ansicht.Pflichtstunden_normal}}</td>
<td>{{Ansicht.Status_normal}}</td>
{% if Ansicht.Prognose_FK %}
<td>{{Ansicht.Prognose_FK.Status}}</td>
<td>{{Ansicht.Prognose_FK.Stunden}}</td>
{% else %}
<td>{{Ansicht.Prognose_FK.Status_2}}</td>
<td>{{Ansicht.Prognose_FK.Stunden_2}}</td>
{% endif %}
{% endfor %}
the filter then would show
those
<td>{{Ansicht.Prognose_FK.Status_2}}</td>
<td>{{Ansicht.Prognose_FK.Stunden_2}}</td>
instead of the first ones when the date is modified, I tried to use javascript but I guess it dont work bc of python objects
my model is
class PrognoseTabelle(models.Model):
Benutzer = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)
Lehrer_FK = models.ForeignKey('LehrerTabelle', on_delete=models.SET_NULL, related_name='LehrerNName', null=True, blank=True)
#######Status 1######
von_Datum = models.DateField(null=True, blank=True)
Status = models.CharField(max_length=20, null=True, blank=True)
Stunden = models.CharField(max_length=20, null=True, blank=True)
bis_Datum = models.DateField(null=True, blank=True)
#######Status 2######
von_Datum_2 = models.DateField(null=True, blank=True)
Status_2 = models.CharField(max_length=20, null=True, blank=True)
Stunden_2 = models.CharField(max_length=20, null=True, blank=True)
bis_Datum_2 = models.DateField(null=True, blank=True)
#######Status 3######

Answer 1

It is impossible to influence the rendered HTML from only server-side code, after it has been rendered and displayed by the user. If I understand you correctly, your intended user interaction with this view/menu looks kind of like this:
User action: The user opens the menu.
Program action: Among other things, a date-input is displayed.
User action: The user inputs a date using the date-input.
Program action: The displayed content changes.
Given, that you cannot influence the rendered HTML with only server-side code in step 4., you have two possibilities to achieve this:
display new rendered HTML
use client-side code (for example JavaScript)
I'm going to explain the first possibility here:
It's probably the easiest to use a django form to render the input.
forms.py:
from django import forms
from django.utils.timezone import localdate
class PrognoseFilterForm(forms.Form):
"""Form for filtering the Prognose table."""
datum = forms.DateField()
somewhere in views.py:
def prognose_tabelle_view(request, *args, **kwargs):
form = PrognoseFilterForm(request.GET, initial={'date': timezone.localdate()})
datum = timezone.localdate()
if form.is_bound() and form.is_valid():
datum = form.cleaned_data['datum']
prognose_query = Ansicht.lehrertabelle_set.all()
prognoseansichten_bis_einschliesslich_datum = prognose_query.filter(
Prognose_FK__von_Datum__lte=datum
)
prognoseansichten_ab_datum = prognose_query.filter(
Prognose_FK__von_Datum__gt=datum
)
return render(
request,
'your_app/prognose_tabelle.html',
context={
'filter_form': form,
'prognosen_bis_datum': prognoseansichten_bis_einschliesslich_datum,
'prognosen_ab_datum': prognoseansichten_ab_datum,
}
)
prognose_tabelle.html:
<form action="{% url '<name of the view according to urls.py>' %}" method="get">
{{ filter_form.as_p }}
<input type="submit">Filtern</input>
</form>
<table>
<tbody>
{% for Ansicht in prognosen_bis_datum %}
<tr>
<th scope="row"></th>
<td>{{Ansicht.Pflichtstunden_normal}}</td>
<td>{{Ansicht.Status_normal}}</td>
<td>{{Ansicht.Prognose_FK.Status}}</td>
<td>{{Ansicht.Prognose_FK.Stunden}}</td>
</tr>
{% endfor %}
{% for Ansicht in prognosen_ab_datum %}
<tr>
<th scope="row"></th>
<td>{{Ansicht.Pflichtstunden_normal}}</td>
<td>{{Ansicht.Status_normal}}</td>
<td>{{Ansicht.Prognose_FK.Status_2}}</td>
<td>{{Ansicht.Prognose_FK.Stunden_2}}</td>
</tr>
{% endfor %}
</tbody>
</table>
When a user clicks the button labelled with "Filtern", the form data is sent to the view via an HTTP-Get-Request in its GET-Parameters. The server then responds with a new HTML page, which the browser then displays to the user.