为ImageField设置新的“路径”值

Question

我有以下情况。项目文件存储在~/django-app/app-old/app中。出于某些原因，我将文件移动到~/django-app/app。应用程序有一些图像，使用ImageField存储。在数据库中，图像有如下路径：

~/django-apps/app-old/app/media/images/blabla.jpeg

因此，我需要在数据库中修复这个路径，如下所示：

~django-apps/app/media/images/blabla.jpeg

为此，我尝试编写管理命令：

from django.core.management.base import BaseCommand, CommandError
from books.models import Book
import string

class Command(BaseCommand):
    help = ''

    def handle(self, *args, **options):
        books = Book.objects.all()
        total = len(books)
        curr = 1

        for book in books:
            print "%d/%d" % (curr, total)
            if book.cover_url != "":
                book.cover_url.path = string.replace(book.cover_url.path, "app-old/", "")
                book.save()
            curr+=1

通过使用此命令，我得到以下错误：

Traceback (most recent call last):
  File "manage.py", line 11, in <module>
    execute_manager(settings)
  File "/usr/local/lib/python2.6/dist-packages/django/core/management/__init__.py", line 438, in execute_manager
    utility.execute()
  File "/usr/local/lib/python2.6/dist-packages/django/core/management/__init__.py", line 379, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python2.6/dist-packages/django/core/management/base.py", line 191, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/local/lib/python2.6/dist-packages/django/core/management/base.py", line 220, in execute
    output = self.handle(*args, **options)
  File "/var/www/dizpers/data/django-apps/app/books/management/commands/fix-covers-path.py", line 23, in handle
    book.cover_url.path = string.replace(book.cover_url.path, "bparser-old/", "")
  File "/usr/local/lib/python2.6/dist-packages/django/db/models/fields/files.py", line 65, in _get_path
    return self.storage.path(self.name)
  File "/usr/local/lib/python2.6/dist-packages/django/core/files/storage.py", line 234, in path
    raise SuspiciousOperation("Attempted access to '%s' denied." % name)
django.core.exceptions.SuspiciousOperation: Attempted access to '/var/www/dizpers/data/django-apps/app-old/app/media/covers/a3d9545d3a17bb68a91749019c95357d.jpeg' denied.

为什么我会收到这条错误信息？我怎样才能修复图像的路径？

UPD1

我的模型包含这样的ImageField：

cover_url = models.ImageField(upload_to=os.path.join(MEDIA_ROOT, "covers"), null=True, default=None)

UPD2

路径属性是只读的。

Answer 1

这应该能行

for book in books:
        print "%d/%d" % (curr, total)
        if book.cover_url != "":
            new_path = string.replace(book.cover_url.path, "app-old/", "")
            book.cover_url = new_path
            book.save()
        curr+=1

Answer 2

由于安全原因，默认文件系统存储阻止使用绝对路径，因此收到此消息。

如果您真的想使用绝对路径

出于安全原因，django-文件强制使用绝对路径，如下所示：

from django.core.files.storage import FileSystemStorage


fs = FileSystemStorage(location=UPLOAD_TO)


class Document(models.Model):
    file = models.FileField(storage=fs, upload_to=UPLOAD_TO)

其中UPLOAD_TO可以是绝对路径。

-回答问题最新情况

如果你不需要这样的安全

那么你应该读一下关于FileField的文档

FileField.upload_to本地文件系统路径，它将被附加到MEDIA_ROOT设置中，以确定url属性的值。

在您的例子中，upload_to='covers'就足够了。

注意，应该将相对路径存储在数据库中。