Django documentation

27. Default manipulators

This example describes Django version 0.96. For the current example, go here.

Each model gets an AddManipulator and ChangeManipulator by default.

Model source code

from django.db import models

class Musician(models.Model):
    first_name = models.CharField(maxlength=30)
    last_name = models.CharField(maxlength=30)

    def __str__(self):
        return "%s %s" % (self.first_name, self.last_name)

class Album(models.Model):
    name = models.CharField(maxlength=100)
    musician = models.ForeignKey(Musician)
    release_date = models.DateField(blank=True, null=True)

    def __str__(self):
        return self.name

Sample API usage

This sample code assumes the above models have been saved in a file mysite/models.py. 

>>> from mysite.models import Musician, Album

>>> from django.utils.datastructures import MultiValueDict

# Create a Musician object via the default AddManipulator.
>>> man = Musician.AddManipulator()
>>> data = MultiValueDict({'first_name': ['Ella'], 'last_name': ['Fitzgerald']})

>>> man.get_validation_errors(data)
{}
>>> man.do_html2python(data)
>>> m1 = man.save(data)

# Verify it worked.
>>> Musician.objects.all()
[<Musician: Ella Fitzgerald>]
>>> [m1] == list(Musician.objects.all())
True

# Attempt to add a Musician without a first_name.
>>> man.get_validation_errors(MultiValueDict({'last_name': ['Blakey']}))
{'first_name': ['This field is required.']}

# Attempt to add a Musician without a first_name and last_name.
>>> man.get_validation_errors(MultiValueDict({}))
{'first_name': ['This field is required.'], 'last_name': ['This field is required.']}

# Attempt to create an Album without a name or musician.
>>> man = Album.AddManipulator()
>>> man.get_validation_errors(MultiValueDict({}))
{'musician': ['This field is required.'], 'name': ['This field is required.']}

# Attempt to create an Album with an invalid musician.
>>> man.get_validation_errors(MultiValueDict({'name': ['Sallies Fforth'], 'musician': ['foo']}))
{'musician': ["Select a valid choice; 'foo' is not in ['', '1']."]}

# Attempt to create an Album with an invalid release_date.
>>> man.get_validation_errors(MultiValueDict({'name': ['Sallies Fforth'], 'musician': ['1'], 'release_date': 'today'}))
{'release_date': ['Enter a valid date in YYYY-MM-DD format.']}

# Create an Album without a release_date (because it's optional).
>>> data = MultiValueDict({'name': ['Ella and Basie'], 'musician': ['1']})
>>> man.get_validation_errors(data)
{}
>>> man.do_html2python(data)
>>> a1 = man.save(data)

# Verify it worked.
>>> Album.objects.all()
[<Album: Ella and Basie>]
>>> Album.objects.get().musician
<Musician: Ella Fitzgerald>

# Create an Album with a release_date.
>>> data = MultiValueDict({'name': ['Ultimate Ella'], 'musician': ['1'], 'release_date': ['2005-02-13']})
>>> man.get_validation_errors(data)
{}
>>> man.do_html2python(data)
>>> a2 = man.save(data)

# Verify it worked.
>>> Album.objects.order_by('name')
[<Album: Ella and Basie>, <Album: Ultimate Ella>]
>>> a2 = Album.objects.get(pk=2)
>>> a2
<Album: Ultimate Ella>
>>> a2.release_date
datetime.date(2005, 2, 13)

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