我有一个django应用程序，它使用python 3在1.6上运行。最近我已将django-storages添加到我的应用程序中。
当我试图保存以前运作良好的模型（记录）时，它会显示以下错误
Traceback (most recent call last):
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/core/handlers/base.py", line 112, in get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/contrib/admin/options.py", line 432, in wrapper
return self.admin_site.admin_view(view)(*args, **kwargs)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/utils/decorators.py", line 99, in _wrapped_view
response = view_func(request, *args, **kwargs)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/views/decorators/cache.py", line 52, in _wrapped_view_func
response = view_func(request, *args, **kwargs)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/contrib/admin/sites.py", line 198, in inner
return view(request, *args, **kwargs)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/utils/decorators.py", line 29, in _wrapper
return bound_func(*args, **kwargs)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/utils/decorators.py", line 99, in _wrapped_view
response = view_func(request, *args, **kwargs)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/utils/decorators.py", line 25, in bound_func
return func(self, *args2, **kwargs2)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/transaction.py", line 371, in inner
return func(*args, **kwargs)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/contrib/admin/options.py", line 1131, in add_view
self.save_model(request, new_object, form, False)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/contrib/admin/options.py", line 860, in save_model
obj.save()
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/base.py", line 545, in save
force_update=force_update, update_fields=update_fields)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/base.py", line 573, in save_base
updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/base.py", line 654, in _save_table
result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/base.py", line 687, in _do_insert
using=using, raw=raw)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/manager.py", line 232, in _insert
return insert_query(self.model, objs, fields, **kwargs)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/query.py", line 1514, in insert_query
return query.get_compiler(using=using).execute_sql(return_id)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/sql/compiler.py", line 902, in execute_sql
for sql, params in self.as_sql():
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/sql/compiler.py", line 860, in as_sql
for obj in self.query.objs
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/sql/compiler.py", line 860, in <listcomp>
for obj in self.query.objs
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/sql/compiler.py", line 858, in <listcomp>
for f in fields
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/fields/files.py", line 252, in pre_save
file.save(file.name, file, save=False)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/fields/files.py", line 87, in save
setattr(self.instance, self.field.name, self.name)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/fields/files.py", line 311, in __set__
self.field.update_dimension_fields(instance, force=True)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/fields/files.py", line 381, in update_dimension_fields
width = file.width
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/core/files/images.py", line 17, in _get_width
return self._get_image_dimensions()[0]
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/core/files/images.py", line 27, in _get_image_dimensions
self.open()
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/db/models/fields/files.py", line 76, in open
self.file.open(mode)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/core/files/base.py", line 121, in open
if not self.closed:
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/django/core/files/base.py", line 59, in _get_closed
return not self.file or self.file.closed
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/storages/backends/s3boto.py", line 406, in _get_file
self.key.get_contents_to_file(self._file)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/boto/s3/key.py", line 1643, in get_contents_to_file
response_headers=response_headers)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/boto/s3/key.py", line 1475, in get_file
query_args=None)
File "/Users/david/.virtualenvs/project/lib/python3.4/site-packages/boto/s3/key.py", line 1529, in _get_file_internal
fp.write(bytes)
TypeError: string argument expected, got 'bytes'
模型
class RequisitionImage(models.Model, ImageRisizeToolbox):
image_id = models.AutoField(primary_key=True)
requisition = models.ForeignKey(Requisition)
description = models.CharField(max_length=80)
image_file = models.ImageField(upload_to=get_file_path, height_field='image_height', width_field='image_width')
thumbnail_file = models.ImageField(upload_to=get_file_path, blank=True, null=True)
sort_order = models.SmallIntegerField(blank=True, null=True)
filetype = models.CharField(max_length=10, blank=True, null=True)
objects = models.Manager()
cust_objects = RequisitionImageManager()
MAX_SIZE = 4000000 # Image file size limit
def __str__(self):
return self.description
当我尝试从管理模型和视图中保存RequisitionImage对象记录时，我收到此错误。
那么如何避免这个错误以及导致它的原因呢？