Working with Dates and Times in the Forms

2019-10-08

HTML5 comes with a bunch of new types for the input fields that are rendered as rich native widgets. Browsers even restrict invalid values and validate the input immediately. Let's explore how we could make use of them in Django forms.

We will be using an Exhibition model with models.DateField, models.TimeField, and models.DateTimeField:

# exhibitions/models.py
from django.db import models
from django.utils.translation import gettext_lazy as _

class Exhibition(models.Model):
    title = models.CharField(_("Title"), max_length=200)
    start = models.DateField(_("Start"))
    end = models.DateField(_("End"), blank=True, null=True)
    opening = models.TimeField(_("Opening every day"))
    closing = models.TimeField(_("Closing every day"))
    vernissage = models.DateTimeField(_("Vernissage"), blank=True, null=True)
    finissage = models.DateTimeField(_("Finissage"), blank=True, null=True)

    class Meta:
        verbose_name = _("Exhibition")
        verbose_name_plural = _("Exhibitions")

    def __str__(self):
        return self.title

Here is a quick model form for the Exhibition model:

# exhibitions/forms.py
from django import forms
from .models import Exhibition

class ExhibitionForm(forms.ModelForm):
    class Meta:
        model = Exhibition
        fields = "__all__"

If we now open a Django shell and create an instance of the model form with some initial values, then print the form as HTML to the console, we will notice, that all date and time fields are rendered as <input type="text" /> and the values for the dates are in a local format, not the ISO standard YYYY-MM-DD:

(venv)$ python manage.py shell
>>> from exhibitions.forms import ExhibitionForm
>>> from datetime import datetime, date, time
>>> form = ExhibitionForm(initial={
...     "start": date(2020, 1, 1),
...     "end": date(2020, 3, 31),
...     "opening": time(11, 0),
...     "closing": time(20, 0),
...     "vernissage": datetime(2019, 12, 27, 19, 0),
...     "finissage": datetime(2020, 4, 1, 19, 0),
>>> })
>>> print(form.as_p())
<p><label for="id_title">Title:</label> <input type="text" name="title" maxlength="200" required id="id_title"></p>
<p><label for="id_start">Start:</label> <input type="text" name="start" value="01.01.2020" required id="id_start"></p>
<p><label for="id_end">End:</label> <input type="text" name="end" value="31.03.2020" id="id_end"></p>
<p><label for="id_opening">Opening every day:</label> <input type="text" name="opening" value="11:00:00" required id="id_opening"></p>
<p><label for="id_closing">Closing every day:</label> <input type="text" name="closing" value="20:00:00" required id="id_closing"></p>
<p><label for="id_vernissage">Vernissage:</label> <input type="text" name="vernissage" value="27.12.2019 19:00:00" id="id_vernissage"></p>
<p><label for="id_finissage">Finissage:</label> <input type="text" name="finissage" value="01.04.2020 19:00:00" id="id_finissage"></p>

Let's modify the model form and customize the date and time inputs. We will extend and use forms.DateInput, forms.TimeInput, and forms.DateTimeInput widgets. We want to show date inputs as <input type="date" />, time inputs as <input type="time" />, and date-time inputs as <input type="datetime-local" />. In addition, the format for the dates should be based on ISO standard.

# exhibitions/forms.py
from django import forms
from .models import Exhibition


class DateInput(forms.DateInput):
    input_type = "date"

    def __init__(self, **kwargs):
        kwargs["format"] = "%Y-%m-%d"
        super().__init__(**kwargs)


class TimeInput(forms.TimeInput):
    input_type = "time"


class DateTimeInput(forms.DateTimeInput):
    input_type = "datetime-local"

    def __init__(self, **kwargs):
        kwargs["format"] = "%Y-%m-%dT%H:%M"
        super().__init__(**kwargs)


class ExhibitionForm(forms.ModelForm):
    class Meta:
        model = Exhibition
        fields = "__all__"

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields["start"].widget = DateInput()
        self.fields["end"].widget = DateInput()
        self.fields["opening"].widget = TimeInput()
        self.fields["closing"].widget = TimeInput()
        self.fields["vernissage"].widget = DateTimeInput()
        self.fields["vernissage"].input_formats = ["%Y-%m-%dT%H:%M", "%Y-%m-%d %H:%M"]
        self.fields["finissage"].widget = DateTimeInput()
        self.fields["finissage"].input_formats = ["%Y-%m-%dT%H:%M", "%Y-%m-%d %H:%M"]

Let's see now in the Django shell if that worked as expected:

(venv)$ python manage.py shell
>>> from exhibitions.forms import ExhibitionForm
>>> from datetime import datetime, date, time
>>> form = ExhibitionForm(initial={
...     "start": date(2020, 1, 1),
...     "end": date(2020, 3, 31),
...     "opening": time(11, 0),
...     "closing": time(20, 0),
...     "vernissage": datetime(2019, 12, 27, 19, 0),
...     "finissage": datetime(2020, 4, 1, 19, 0),
>>> })
>>> print(form.as_p())
<p><label for="id_title">Title:</label> <input type="text" name="title" maxlength="200" required id="id_title"></p>
<p><label for="id_start">Start:</label> <input type="date" name="start" value="2020-01-01" required id="id_start"></p>
<p><label for="id_end">End:</label> <input type="date" name="end" value="2020-03-31" id="id_end"></p>
<p><label for="id_opening">Opening every day:</label> <input type="time" name="opening" value="11:00:00" required id="id_opening"></p>
<p><label for="id_closing">Closing every day:</label> <input type="time" name="closing" value="20:00:00" required id="id_closing"></p>
<p><label for="id_vernissage">Vernissage:</label> <input type="datetime-local" name="vernissage" value="2019-12-27T19:00" id="id_vernissage"></p>
<p><label for="id_finissage">Finissage:</label> <input type="datetime-local" name="finissage" value="2020-04-01T19:00" id="id_finissage"></p>