Django UnicodeEncodeError when displaying formset: ascii codec can't encode characters

问题

I am trying to simply display Model formset in django template. I get the following error

Here is what I am trying to display: the actual formset within a form

In the view.py, here is the related code snippet:

 #
 # create Address Model Form Set
 #
 AddressFormSet = modelformset_factory( Address, form=businessForms.AddressModelForm )

if request.method == 'GET':

    businessModelForm = businessForms.BusinessModelForm( instance = business )

    addressModelFormSet = AddressFormSet( queryset=Address.objects.filter(business__id=business.id) )
    #addressModelFormSet = AddressFormSet( )

    print addressModelFormSet.is_valid()  /* prints False */
    print addressModelFormSet.errors     /* prints [] empty list */

    return render(request, "business_profile.html", { 'businessModelForm' : businessModelForm,
                                                      'addressModelFormSet': addressModelFormSet })

I assume the validity of the form has nothing to do with this error since we check validity upon POST request, yet I could be wrong. No error list is shown though for the formset.

The AddressModelForm:

class AddressModelForm(ModelForm):

    class Meta:
        model = Address
        fields = ['street_address', 'address_line2', 'city', 'state', 'zip_code']

The model definition:

class Country(models.Model):
    country_name = models.CharField(max_length = 50)
    country_code = models.CharField(max_length = 2)
    phone_code = models.CharField(max_length = 3, default = '000')
    country_name_ar = models.CharField(max_length = 50, default = '')

     #many-to-many fields
    currencies = models.ManyToManyField(Currency)

    def __str__(self):
        return "%s" % self.country_name

class City(models.Model):
    city_name = models.CharField(max_length = 93)
    city_name_ar = models.CharField(max_length = 93, default = '')
    country = models.ForeignKey(Country)

    def __str__(self):
        return ("%s" % self.city_name) + "," + str(self.country)

class Address(models.Model):
    street_address = models.CharField(max_length = 500)
    address_line2 = models.CharField(max_length = 500, default = '')
    city = models.ForeignKey(City) # country included implicitly in city
    zip_code = models.CharField(max_length = 5, default = '')
    state = models.CharField(max_length = 2, default = '')

    def __str__(self):
        usStr = ("%s" % self.street_address) + "," + str(self.city) + "," + self.state + "," + self.zip_code
        nonUsStr = ("%s" % self.street_address) + "," + str(self.city)

        if self.state != '':
            return usStr
        else:
            return usStr

I am suspecting the fact that city model has city_name_ar which is Arabic field for city name ...

UPDATE If I remove 'city' from AddressModelForm, or override the field to be CharField, I don't get this error, however, I get text field with city ID which is useless ...

回答1:

You're using Python 2.x. Under 2.x, models should either have a __unicode__ method rather than or in addition to a __str__ method, and each method should return the appropriate type (unicode for __unicode__, encoded bytes for __str__) or you should use the python_2_unicode_compatible decorator if you're on a sufficiently recent version of Django. If you're planning to stay on 2.x for the immediately future, I'd recommend just writing __unicode__ methods and not bothering with the decorator since you're concatenating string representations and I'm not quite sure what it does with that.

Some relevant docs are:

https://docs.djangoproject.com/en/1.8/ref/utils/#django.utils.encoding.python_2_unicode_compatible

https://docs.djangoproject.com/en/1.8/topics/python3/#str-and-unicode-methods

Either way, you should avoid converting database values (which are passed around as Unicode object) without specifying the encoding. Generally it's easiest to just define a method that returns unicode, eg:

class Country(models.Model):
    # as above, except
    def __unicode__(self):
         return self.country_name

Or:

@python_2_unicode_compatible
class Country(models.Model):
    # as above, except
    def __str__(self):
         return self.country_name

Similarly for your other models:

class City(models.Model):
    ...
    def __unicode__(self):
        return self.city_name + "," + unicode(self.country)

Or (untested, you might need to call unicode(self.country) here as well):

@python_2_unicode_compatible
class City(models.Model):
    ...
    def __str__(self):
        return self.city_name + "," + str(self.country)

来源：https://stackoverflow.com/questions/32557468/django-unicodeencodeerror-when-displaying-formset-ascii-codec-cant-encode-char

标签

python

django

unicode

modelform

formset