Displaying the local time for datetime attribute of a model object in Django

Question

I'm trying to make it so the datetime field attribute of a model object is displayed in the template as the local time of the timezone of the current user. The default timezone in my settings is UTC. Here is an example model:

models.py

class Basic(models.Model):
    name = models.CharField(max_length=128)
    created_at = models.DateTimeField(auto_now_add=True

The data I want to display is in a table made with django-tables2. However, I already tried two methods and both of them did not work:

tables.py attempt 1:

class ShipperDataFileDocumentTable(tables.Table):
    created_at = tables.TemplateColumn('''
                                        {% load tz %}
                                        {% localtime on %}
                                            {{ record.created_at }}
                                        {% endlocaltime %}
                                      ''')
    class Meta:
        model = Basic
        fields = ('name', 'created_at')

tables.py attempt 2:

class ShipperDataFileDocumentTable(tables.Table):
    created_at = tables.TemplateColumn('''
                                        {% load tz %}
                                        {{ record.created_at|localtime }}
                                      ''')
    class Meta:
        model = Basic
        fields = ('name', 'created_at')

Both of these methods ended up not changing the time at all. For example, I made an object at 12:00 PM EST. Normally, the template would display it as 4:00 PM in UTC. However, even with those edits, it still displayed the time as 4:00 PM. I'm not sure what I'm doing wrong.

EDIT: Is there a way to detect the user's current timezone? I already tried django-easy-timezones, but for some reason that doesn't work.

Answer 1

Django provide a way to handle this:

1. Enable timezone support:

   Set UZE_TZ = True in your settings file.

2. Then implement a way for selecting the user time zone:

   An example with a form and a middleware. But a simpler(than the explicit form) solution IMO is to detect it in js, then put it in the user session/cookie. For example with moment.js:

   Session['tz'] = moment.tz.guess()

3. Then render the localtime in the template.

Or if you don't want to handle it server side and prefer to do it client side make django set the time zone to iso 8601 in the template then convert it in js or with jQuery.

Plenty of solution but still a PITA...

Answer 2

Another poorly answered question that needs my help. Using JavaScript to convert the time would be a valid way to go about it, but due to its complexity I would recommend a library like moment.js. There is a simpler way however, than learning a new JS framework. django-tables2 thinks you want the datetime object in GMT, but you can instead tell it to use local for the display. If you read the python documentation, UZE_TZ = True is a bad idea for production grade code because your datetimes will be stored as a local time, making synchronization across timezones next to impossible. What you want is a datetime object that's timezone aware, like this 2018-03-07 08:34:32.212841-05. Your code created_at = models.DateTimeField(auto_now_add=True) creates just such an object, so step one is done correctly. Step two, display the time to the user in local time. Add this to your model (I hard-coded Eastern for demonstration, if you read the pytz docs, there's also a localize function):

def localTimeCreated(self): return self.created_at.astimezone(pytz.timezone('US/Eastern')).strftime("%H:%M:%S %p")

Now we need to exclude the old created_at and reference the new method. Go to your table class, add this property, and change Meta:

createdFormatted = tables.Column(accessor='localTimeCreated', verbose_name='Created') # verbose_name = column header

class Meta:
    model = Basic
    fields = ('name', 'createdFormatted')
    exclude = ('created_at')
    sequence = ('createdFormatted', 'name' ) #default: extra columns at the end
    attrs = {"class" : "table-striped table-bordered"}
    empty_text = "User not found."

The last 2 properties are unrelated but good for a professional look.