I apologize, where it says CourseStudent replace with Student (I
changed the name for the post).
On Feb 12, 2:39 pm, chazmatazz <charles.m.dietr...@gmail.com> wrote:
> Hi Django users,
>
> I want a ManyToManyField(A) to be shown in a textarea as a formatted
> list of a model field _x_ in the corresponding related model A (not a
> list of the A's pk field, which is easier). If a value for _x_ that
> does not exist in A is added, then I want a new record added to A (by
> implication, field _x_ is unique).
>
> I have recently implemented this as follows, and it works but I (I
> think) but I want to know if I went about it the right way. Any
> comments would be appreciated. (Also, it's a useful bit of code, so
> you should check it out.)
>
> As an example, consider the following models for University courses:
>
> class Student(models.Model):
> email = models.EmailField(unique=True)
> ...
>
> class Course(models.Model):
> name = models.CharField(max_length = 100)
> students = models.ManyToManyField(Student)
> ...
>
> I want the administrator to be able to enter a comma separated list of
> emails into a textarea. If the email does not exist in Student, a new
> Student should be added.
>
> To solve this, I have
>
> class CourseAdmin(admin.ModelAdmin):
> form = CourseForm
> ...
>
> class CourseForm(ModelForm):
> students = MultiEmailField()
> def __init__(self, *args, **kwargs):
> super(CourseForm, self).__init__(*args, **kwargs)
> if self.initial.has_key('students'):
> self.initial['students'] = ",".join(
> [course_student.email for course_student in
> CourseStudent.objects.filter(pk__in = self.initial['students'])])
>
> def save(self, *args, **kwargs):
> emails = self.cleaned_data['students']
> for email in emails:
> # create a new Student if one does not already exist
> form = StudentForm({'email': email})
> if form.is_valid():
> form.save()
> self.cleaned_data['students'] = Student.objects.filter
> (email__in=emails)
> return super(CourseForm, self).save(*args, **kwargs)
>
> class Meta:
> model = Course
>
> class StudentForm(ModelForm):
> class Meta:
> model = Student
>
> MultiEmailField is essentially the same as specified
> inhttp://docs.djangoproject.com/en/dev/ref/forms/validation/#form-field....
> Assume is_valid_email is defined, and don't worry about the details of
> MultiEmailField (the actual implementation lets you use spaces,
> semicolons, commas and newlines as delimiters):
>
> class MultiEmailField(forms.Field):
> def clean(self, value):
> """
> Check that the field contains one or more comma-separated
> emails
> and normalizes the data to a list of the email strings.
> """
> if not value:
> raise forms.ValidationError('Enter at least one e-mail
> address.')
> emails = value.split(',')
> for email in emails:
> if not is_valid_email(email):
> raise forms.ValidationError('%s is not a valid e-mail
> address.' % email)
>
> # Always return the cleaned data.
> return emails
>
> Please comment on my code in CourseForm:
>
> * Does the logic belong here instead of in the model?
> * Are there bugs that you can see?
> * Is this the right way to do things?
> * Is it elegant? (I think the answer is no.)
>
> Any comments are appreciated.
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