重寫模型保存（）導致錯誤的Django管理

Question

我有，我想在Django管理保存模型

class Product(models.Model): 
    # other fields 
    img1 = models.ImageField(upload_to='%s/%s/1/large/' % (category, prod_no)) 
    img1_thumb = models.ImageField(upload_to='%s/%s/1/thumbnail/' % (category, prod_no), editable=False) 

    def save(self, *args, **kwargs): 
     newImg1 = resizeImg(self.img1, (75, 112)) 
     self.img1_thumb = newImg1 
     super(Product, self).save(*args, **kwargs) 

容量調整圖像功能

def resizeImg(image, size): 
    try: 
     if imghdr.what(image) == 'jpeg': 
      img = Image.open(image) 
      img.thumbnail(size, Image.ANTIALIAS) 

      # this is how to save the img 
      # img.save(filename + '.jpg', 'JPEG', quality=75) 

      return img 
     else: 
      return 'not_jpg' 

    except Exception, e: 
     return 'exception' 

保存這在Django管理員創建此錯誤

AttributeError at /admin/myapp/product/add/ 
_committed 

更新 - 完全回溯：

Environment: 


Request Method: POST 
Request URL: http://127.0.0.1:8000/admin/myapp/product/add/ 

Django Version: 1.3.1 
Python Version: 2.7.1 
Installed Applications: 
['django.contrib.auth', 
'django.contrib.contenttypes', 
'django.contrib.sessions', 
'django.contrib.sites', 
'django.contrib.messages', 
'django.contrib.staticfiles', 
'django.contrib.admin', 
'bc'] 
Installed Middleware: 
('django.middleware.common.CommonMiddleware', 
'django.contrib.sessions.middleware.SessionMiddleware', 
'django.middleware.csrf.CsrfViewMiddleware', 
'django.middleware.csrf.CsrfResponseMiddleware', 
'django.contrib.auth.middleware.AuthenticationMiddleware', 
'django.contrib.messages.middleware.MessageMiddleware') 


Traceback: 
File "/Library/Python/2.7/site-packages/django/core/handlers/base.py" in get_response 
    111.       response = callback(request, *callback_args, **callback_kwargs) 
File "/Library/Python/2.7/site-packages/django/contrib/admin/options.py" in wrapper 
    307.     return self.admin_site.admin_view(view)(*args, **kwargs) 
File "/Library/Python/2.7/site-packages/django/utils/decorators.py" in _wrapped_view 
    93.      response = view_func(request, *args, **kwargs) 
File "/Library/Python/2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func 
    79.   response = view_func(request, *args, **kwargs) 
File "/Library/Python/2.7/site-packages/django/contrib/admin/sites.py" in inner 
    197.    return view(request, *args, **kwargs) 
File "/Library/Python/2.7/site-packages/django/utils/decorators.py" in _wrapper 
    28.    return bound_func(*args, **kwargs) 
File "/Library/Python/2.7/site-packages/django/utils/decorators.py" in _wrapped_view 
    93.      response = view_func(request, *args, **kwargs) 
File "/Library/Python/2.7/site-packages/django/utils/decorators.py" in bound_func 
    24.     return func(self, *args2, **kwargs2) 
File "/Library/Python/2.7/site-packages/django/db/transaction.py" in inner 
    217.     res = func(*args, **kwargs) 
File "/Library/Python/2.7/site-packages/django/contrib/admin/options.py" in add_view 
    882.     self.save_model(request, new_object, form, change=False) 
File "/Library/Python/2.7/site-packages/django/contrib/admin/options.py" in save_model 
    665.   obj.save() 
File "/Users/rocky/Projects/BestChoose/bc/models.py" in save 
    66.   super(Product, self).save(*args, **kwargs) 
File "/Library/Python/2.7/site-packages/django/db/models/base.py" in save 
    460.   self.save_base(using=using, force_insert=force_insert, force_update=force_update) 
File "/Library/Python/2.7/site-packages/django/db/models/base.py" in save_base 
    543.       for f in meta.local_fields if not isinstance(f, AutoField)] 
File "/Library/Python/2.7/site-packages/django/db/models/fields/files.py" in pre_save 
    253.   if file and not file._committed: 
File "/Library/Python/2.7/site-packages/PIL-1.1.7-py2.7-macosx-10.7-intel.egg/Image.py" in __getattr__ 
    512.   raise AttributeError(name) 

Exception Type: AttributeError at /admin/myapp/product/add/ 
Exception Value: _committed 

Answer 1

你不能做到這一點：

newImg1 = resizeImg(self.img1, (75, 112)) 
self.img1_thumb = newImg1 

您分配一個圖像到期望一個文件中的字段。您需要先從圖像中創建一個文件。而不是再次輸入全部，請參閱this snippet，詳細說明正確的方法。

您還可以使用任何thumbnailing applications來簡化您的代碼。 solr-thumbnail是最受歡迎的之一。