UnicodeDecodeError: 'ascii' codec can't decode byte 0xcb in position 0: ordinal not in range(128) when using tastypie

Question

I am testing tastypie 1.9 with Django 1.4 to create a basic REST API for my website. I am following the initial steps in documentation, where I got stuck.

I am running Django globally, and not using virtualenv for this specific implementation. It says in the browser A server error occurred. Please contact the administrator.. I am running this in django server only.

This is the error message that is coming in terminal when I try to access http://127.0.0.1:8000/api/sessionuserround/?format=json

[20/Jun/2013 10:26:19] "GET /api/sessionuserround/?format=json HTTP/1.1" 500 99752
Traceback (most recent call last):
  File "/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/usr/local/lib/python2.7/site-packages/django/contrib/staticfiles/handlers.py", line 67, in __call__
    return self.application(environ, start_response)
  File "/usr/local/lib/python2.7/site-packages/django/core/handlers/wsgi.py", line 241, in __call__
    response = self.get_response(request)
  File "/usr/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 146, in get_response
    response = debug.technical_404_response(request, e)
  File "/usr/local/lib/python2.7/site-packages/django/views/debug.py", line 443, in technical_404_response
    'reason': smart_str(exception, errors='replace'),
  File "/usr/local/lib/python2.7/site-packages/django/utils/encoding.py", line 116, in smart_str
    return str(s)
  File "/usr/local/lib/python2.7/site-packages/django/core/urlresolvers.py", line 235, in __repr__
    return smart_str(u'<%s %s (%s:%s) %s>' % (self.__class__.__name__, self.urlconf_name, self.app_name, self.namespace, self.regex.pattern))
UnicodeDecodeError: 'ascii' codec can't decode byte 0xcb in position 0: ordinal not in range(128)
[20/Jun/2013 10:26:40] "GET /api/sessionuserround/?format=json HTTP/1.1" 500 59
Traceback (most recent call last):
  File "/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/usr/local/lib/python2.7/site-packages/django/contrib/staticfiles/handlers.py", line 67, in __call__
    return self.application(environ, start_response)
  File "/usr/local/lib/python2.7/site-packages/django/core/handlers/wsgi.py", line 241, in __call__
    response = self.get_response(request)
  File "/usr/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 146, in get_response
    response = debug.technical_404_response(request, e)
  File "/usr/local/lib/python2.7/site-packages/django/views/debug.py", line 443, in technical_404_response
    'reason': smart_str(exception, errors='replace'),
  File "/usr/local/lib/python2.7/site-packages/django/utils/encoding.py", line 116, in smart_str
    return str(s)
  File "/usr/local/lib/python2.7/site-packages/django/core/urlresolvers.py", line 235, in __repr__
    return smart_str(u'<%s %s (%s:%s) %s>' % (self.__class__.__name__, self.urlconf_name, self.app_name, self.namespace, self.regex.pattern))
UnicodeDecodeError: 'ascii' codec can't decode byte 0xcb in position 0: ordinal not in range(128)

These are my related files:

api.py which exists in sal (name of my app):

from tastypie.resources import ModelResource
from sal.models import SessionUserRoundMap


class SessionUserRoundResource(ModelResource):

    class Meta:
        queryset = SessionUserRoundMap.objects.all()

Here's urls.py:

from django.conf.urls.defaults import *
from sal.api import SessionUserRoundResource

sessionuserround_resource = SessionUserRoundResource

urlpatterns = patterns('',
                      (r'ˆapi/', include(sessionuserround_resource.urls)),
                       )

Relevant code in models.py:

class SessionRoundMap(models.Model):

    session_id = models.ForeignKey(Session)
    num_of_rounds = models.IntegerField()

    def __unicode(self):
        text = "Session ID: " + str(self.session_id)
        return text

class SessionUserRoundMap(models.Model):
    user_id = models.ForeignKey(BssUser)
    session_id = models.ForeignKey(Session)
    round_no = models.IntegerField()

    def __unicode__(self):
        return self.user_id + ' ' + self.session_id + ' ' + round_no

Relevant code in settings.py:

INSTALLED_APPS = (
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.sites',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    # Uncomment the next line to enable the admin:
    # 'django.contrib.admin',
    'admin',
    'tastypie',
)

MIDDLEWARE_CLASSES = (
    'django.middleware.common.CommonMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    # Uncomment the next line for simple clickjacking protection:
    # 'django.middleware.clickjacking.XFrameOptionsMiddleware',
)

Right now, my views.py is empty.

Here's requirements.txt:

Django==1.4.5
defusedxml==0.4.1
distribute==0.6.40
django-tastypie==0.9.15
dulwich==0.9.0
hg-git==0.4.0
lxml==3.2.1
mercurial==2.6.2
mimeparse==0.1.3
python-dateutil==1.5
python-mimeparse==0.1.4
vboxapi==1.0
virtualenv==1.9.1
wsgiref==0.1.2

How can I solve this problem? Please help!

Answer 1

The error was coming up because some of the models in my models were not returning a proper unicode encoded response when being instantiated.

This was because of a typo in my models.py:

class SessionRoundMap(models.Model):

    session_id = models.ForeignKey(Session)
    num_of_rounds = models.IntegerField()

    def __unicode(self):
        text = "Session ID: " + str(self.session_id)
        return text

It should have been this instead:

class SessionRoundMap(models.Model):

    session_id = models.ForeignKey(Session)
    num_of_rounds = models.IntegerField()

    def __unicode__(self):
        text = "Session ID: " + str(self.session_id)
        return text

The unicode method wasn't written properly, which was causing this error.

Answer 2

I got this error after adding translation to my site using the ugettext helper i.e.

from django.utils.translation import ugettext as _

So anything with non-ascii text would throw these errors, i.e. accents

messages.success(request, _('Location {0} was deleted.'.format(location_id)))

Specifying the string is unicode by adding the u around it fixed it:

messages.success(request, _(u'Location {0} was deleted.'.format(location_id)))