create row of date while creating superuser

Question

models.py

TITLE = (
    ('Classroom', 'Classroom'),
    ('Playground', 'Playground'),
    ('Staff Room','Staff Room'),
)

class Location(models.Model):
    user = models.ForeignKey(User,null=True)
    title = models.CharField('Incident Type', max_length=200,default=TITLE)
    parent_location_id = models.CharField('Parent Location', max_length=100, null=True, blank=True)
    is_active = models.BooleanField('Is Active', default=True)

def location_title(sender, instance, created, **kwargs):        
    if instance.is_superuser and not instance.location.is_active:

        instance.location.is_active=True
        instance.location.save()

post_save.connect(location_title, sender=User)

I want to insert the default data into database with certain conditions.This should happen while creating superuser via manage.py createsuperuser comment.

I don't know it is possible with django,but it is the requirement.I tried with the above code.I am getting the error "AttributeError: 'User' object has no attribute 'location' " while creating superuser.

The sample what i required is given below

Answer 1

Try this function as signal handler:

def location_title(sender, instance, created, **kwargs):
    # Don't fire up on updates.
    if not created:
        return

    # Only handle new superusers.
    if not instance.is_superuser or not instance.is_active:
        return

    # Create a `Location` entry for new superuser.
    l = Location(user_id=instance.pk)
    l.save()

post_save.connect(location_title, sender=User)

Adding choices to model field:

Django CharField has a named argument choices that allows you to give the end user a list of possible values, and a proper validation of them in forms. The format of the iterable is as follows <internal_value>, <display_value> . Once a field has been passed a choices argument, you can access display value connected to it's internal value with instance.get_<field_name>_display() method.

The choices iterable could look like this:

class Location(models.Model):
    class Title:
        CLASSROOM = 'classroom'
        PLAYGROUND = 'playground'
        STAFF_ROOM = 'staff_room'

    TITLE_CHOICES = (
        (Title.CLASSROOM, 'Classroom'),
        (Title.PLAYGROUND, 'Playground'),
        (Title.STAFF_ROOM, 'Staff Room'),
    )

    user = models.ForeignKey(User,null=True)
    title = models.CharField('Incident Type', max_length=200,choices=TITLE_CHOICES,default=Title.CLASSROOM)
    parent_location_id = models.CharField('Parent Location', max_length=100, null=True, blank=True)
    is_active = models.BooleanField('Is Active', default=True)

The final solution is the following:

class Location(models.Model):
    class Title:
        CLASSROOM = 'classroom'
        PLAYGROUND = 'playground'
        STAFF_ROOM = 'staff_room'

    BASE_LOCATION = Title.CLASSROOM

    TITLE_CHOICES = (
        (Title.CLASSROOM, 'Classroom'),
        (Title.PLAYGROUND, 'Playground'),
        (Title.STAFF_ROOM, 'Staff Room'),
    )

    user = models.ForeignKey(User,null=True)
    title = models.CharField('Incident Type', max_length=200,choices=TITLE_CHOICES,default=Title.CLASSROOM)
    parent_location_id = models.CharField('Parent Location', max_length=100, null=True, blank=True)
    is_active = models.BooleanField('Is Active', default=True)


def location_title(sender, instance, created, **kwargs):
    # Don't fire up on updates.
    if not created:
        return

    # Only handle new superusers.
    if not instance.is_superuser or not instance.is_active:
        return

    # Create a `Location` entry for new superuser.
    base = Location(user_id=instance.pk, title=Location.BASE_LOCATION)
    base.save()

    for value, _ in Location.TITLE_CHOICES:
        if value == Location.BASE_LOCATION:
            continue

        l = Location(user_id=instance.pk, title=value, parent_location_id=base.pk)
        l.save()

post_save.connect(location_title, sender=User)

Answer 2

When you create the user or superuser the model instance is created but it does not have corresponding location row. Hence, accessing instance.location.is_active gives you the error.

You can update the signal handler to create the location instance first and then set appropriate attributes. As below:

def location_title(sender, instance, created, **kwargs):     
    #also check for created flag   
    if created and instance.is_superuser:
        location = Location(user=instance)
        location.is_active=True
        location.save()

post_save.connect(location_title, sender=User)

If you want to choices for title field you can define that in field. Your definition of the title field is not correct, change it to

title = models.CharField('Incident Type', max_length=200, choices=TITLE,  
                         default='Classroom') 

You are incorrectly using detfault=TITLE instead of choices=TITLE .