TypeError coercing à Unicode: besoin d'une chaîne ou d'un tampon

Question

Dans un projet Django, j'essaie de transmettre l'URL à une instance de type voulu. Les commentaires sont appliqués à un Want. J'ai essayé de comprendre cette erreur mais je suis perplexe.

Cette fonction:

 def comment_email(request, comment, **kwargs): 
     want = get_object_or_404(Want, id=comment.object_pk) 
     url = want.get_absolute_url 
     print url 

jette cette erreur

Environment: 

Request Method: POST 
Request URL: http://localhost:8000/comments/post/ 
Django Version: 1.2.3 
Python Version: 2.7.0 
Installed Applications: 
['django.contrib.auth', 
'django.contrib.contenttypes', 
'django.contrib.sessions', 
'django.contrib.sites', 
'django.contrib.messages', 
'django.contrib.admin', 
'django.contrib.comments', 
'django.contrib.markup', 
'src', 
'lib.tagging', 
'lib.markdown', 
'lib.avatar', 
'ajaxcomments', 
'south'] 
Installed Middleware: 
('django.middleware.common.CommonMiddleware', 
'django.contrib.sessions.middleware.SessionMiddleware', 
'django.middleware.csrf.CsrfViewMiddleware', 
'django.contrib.auth.middleware.AuthenticationMiddleware', 
'django.contrib.messages.middleware.MessageMiddleware') 


Traceback: 
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response 
    100.      response = callback(request, *callback_args, **callback_kwargs) 
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/ajaxcomments/utils.py" in wrapped 
    57.   return func(*args, **kwargs) 
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view 
    76.      response = view_func(request, *args, **kwargs) 
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/views/decorators/http.py" in inner 
    37.    return func(request, *args, **kwargs) 
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/contrib/comments/views/comments.py" in post_comment 
    127.   request = request 
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/dispatch/dispatcher.py" in send 
    162.    response = receiver(signal=self, sender=sender, **named) 
File "/Users/emilepetrone/code/apprentice2/src/utils.py" in comment_email 
    24. print url 
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/base.py" in __repr__ 
    344.    u = unicode(self) 

Exception Type: TypeError at /comments/post/ 
Exception Value: coercing to Unicode: need string or buffer, Want found 

Voici le modèle Want:

 class Want(models.Model): 

     pub_date =   models.DateTimeField(default=datetime.now,auto_now_add=True,db_index=True) 
     body = models.TextField(default='',max_length=1000) 
     body_html = models.TextField(editable=False, blank=True) 

     #Metadata 
     mentee = models.ForeignKey(User) 
     points = models.IntegerField(default=3) 
     enable_comments = models.BooleanField(default=True) 
     featured = models.BooleanField(default=False) 

     #Tags 
     tags = TagField(help_text="Autocomplete") 

     def get_tags(self): 
     return Tag.objects.get_for_object(self)  

     class Meta: 
     ordering = ['-pub_date'] 

     def __unicode__(self): 
     return self 

     def save(self): 
     self.body_html = markdown(self.body) 
     super(Want, self).save() 

     def get_absolute_url(self): 
     return ({ 'object_id': self.id }) 
     get_absolute_url = models.permalink(get_absolute_url) 

Merci pour votre aide!

Answer 1

Je pense que le problème est

def __unicode__(self): 
    return self 

qui doit retourner une chaîne de caractères Unicode plutôt que d'une instance « Voulez-vous ». Je ne suis pas sûr de ce que vous voulez à la place - peut-être "self.id"