# Django 5.2.9 문서

# 파일 관리하기

이 문서는 Django의 유저에 의해 업로드된 파일에 접근하는 파일 접근 API를 설명합니다. The lower level API는 충분히 다른 목적으로 사용할 수 있을만큼 범용적입니다. 만약 “정적 파일” (JS, CSS 등)을 관리하고 싶다면, :doc:`/howto/static-files/index`를 참고하세요.

기본값으로, Django는 `MEDIA_ROOT`와 :setting:`MEDIA_URL` 설정을 이용하여 파일을 로컬로 관리합니다. 아래 예시에서는 이러한 기본값을 이용한다고 가정합니다.

그러나, Django는 파일을 어디에, 어떻게 저장할지 완전히 커스터마이즈 할 수 있도록 커스텀 file storage systems 를 기록할 수 있는 방법을 제공합니다. 이 문서의 아래 절반은 이 저장 시스템이 어떻게 작동하는지 설명합니다.

## 모델에서 파일 다루기

`FileField` 또는 :class:`~django.db.models.ImageField`를 사용하는 경우, Django는 해당 파일을 다룰 때 사용할 수 있는 API를 제공합니다.

아래, 이미지를 저장하기 위해 :class:`~django.db.models.ImageField`를 사용하는 모델을 예로 들어봅시다:

    from django.db import models

    class Car(models.Model):
        name = models.CharField(max_length=255)
        price = models.DecimalField(max_digits=5, decimal_places=2)
        photo = models.ImageField(upload_to="cars")
        specs = models.FileField(upload_to="specs")

Any `Car` instance will have a `photo` attribute that you can use to get at the details of the attached photo:

    >>> car = Car.objects.get(name="57 Chevy")
    >>> car.photo
    <ImageFieldFile: cars/chevy.jpg>
    >>> car.photo.name
    'cars/chevy.jpg'
    >>> car.photo.path
    '/media/cars/chevy.jpg'
    >>> car.photo.url
    'https://media.example.com/cars/chevy.jpg'

이 객체 –예시에서 `car.photo`–는 `File` 객체로서, 아래 나열된 메소드와 속성을 모두 가지고 있습니다.

참고

파일 저장은 모델을 데이터베이스에 저장하는 과정의 일부이기 때문에, 디스크에 저장되는 실제 파일명은 모델 저장이 끝나기 전까지는 확신할 수 없다.

For example, you can change the file name by setting the file’s `name` to a path relative to the file storage’s location (`MEDIA_ROOT` if you are using the default `FileSystemStorage`):

    >>> import os
    >>> from django.conf import settings
    >>> initial_path = car.photo.path
    >>> car.photo.name = "cars/chevy_ii.jpg"
    >>> new_path = os.path.join(settings.MEDIA_ROOT, car.photo.name)
    >>> # Move the file on the filesystem
    >>> os.rename(initial_path, new_path)
    >>> car.save()
    >>> car.photo.path
    '/media/cars/chevy_ii.jpg'
    >>> car.photo.path == new_path
    True

To save an existing file on disk to a `FileField`:

    >>> from pathlib import Path
    >>> from django.core.files import File
    >>> path = Path("/some/external/specs.pdf")
    >>> car = Car.objects.get(name="57 Chevy")
    >>> with path.open(mode="rb") as f:
    ...     car.specs = File(f, name=path.name)
    ...     car.save()
    ...

참고

While `ImageField` non-image data attributes, such as `height`, `width`, and `size` are available on the instance, the underlying image data cannot be used without reopening the image. For example:

    >>> from PIL import Image
    >>> car = Car.objects.get(name="57 Chevy")
    >>> car.photo.width
    191
    >>> car.photo.height
    287
    >>> image = Image.open(car.photo)
    # Raises ValueError: seek of closed file.
    >>> car.photo.open()
    <ImageFieldFile: cars/chevy.jpg>
    >>> image = Image.open(car.photo)
    >>> image
    <PIL.JpegImagePlugin.JpegImageFile image mode=RGB size=191x287 at 0x7F99A94E9048>

## `파일` 객체

Internally, Django uses a `django.core.files.File` instance any time it needs to represent a file.

Most of the time you’ll use a `File` that Django’s given you (i.e. a file attached to a model as above, or perhaps an uploaded file).

If you need to construct a `File` yourself, the easiest way is to create one using a Python built-in `file` object:

    >>> from django.core.files import File

    # Create a Python file object using open()
    >>> f = open("/path/to/hello.world", "w")
    >>> myfile = File(f)

Now you can use any of the documented attributes and methods of the `File` class.

Be aware that files created in this way are not automatically closed. The following approach may be used to close files automatically:

    >>> from django.core.files import File

    # Create a Python file object using open() and the with statement
    >>> with open("/path/to/hello.world", "w") as f:
    ...     myfile = File(f)
    ...     myfile.write("Hello World")
    ...
    >>> myfile.closed
    True
    >>> f.closed
    True

Closing files is especially important when accessing file fields in a loop over a large number of objects. If files are not manually closed after accessing them, the risk of running out of file descriptors may arise. This may lead to the following error:

    OSError: [Errno 24] Too many open files

## File storage

Behind the scenes, Django delegates decisions about how and where to store files to a file storage system. This is the object that actually understands things like file systems, opening and reading files, etc.

Django’s default file storage is `'``django.core.files.storage.FileSystemStorage``'`. If you don’t explicitly provide a storage system in the `default` key of the `STORAGES` setting, this is the one that will be used.

See below for details of the built-in default file storage system, and see 커스텀 스토리지 클래스를 작성하는 방법 for information on writing your own file storage system.

### Storage objects

Though most of the time you’ll want to use a `File` object (which delegates to the proper storage for that file), you can use file storage systems directly. You can create an instance of some custom file storage class, or – often more useful – you can use the global default storage system:

    >>> from django.core.files.base import ContentFile
    >>> from django.core.files.storage import default_storage

    >>> path = default_storage.save("path/to/file", ContentFile(b"new content"))
    >>> path
    'path/to/file'

    >>> default_storage.size(path)
    11
    >>> default_storage.open(path).read()
    b'new content'

    >>> default_storage.delete(path)
    >>> default_storage.exists(path)
    False

See File storage API for the file storage API.

### The built-in filesystem storage class

Django ships with a `django.core.files.storage.FileSystemStorage` class which implements basic local filesystem file storage.

For example, the following code will store uploaded files under `/media/photos` regardless of what your `MEDIA_ROOT` setting is:

    from django.core.files.storage import FileSystemStorage
    from django.db import models

    fs = FileSystemStorage(location="/media/photos")

    class Car(models.Model):
        ...
        photo = models.ImageField(storage=fs)

Custom storage systems work the same way: you can pass them in as the `storage` argument to a `FileField`.

### Using a callable

You can use a callable as the `storage` parameter for `FileField` or `ImageField`. This allows you to modify the used storage at runtime, selecting different storages for different environments, for example.

Your callable will be evaluated when your models classes are loaded, and must return an instance of `Storage`.

예시:

    from django.conf import settings
    from django.db import models
    from .storages import MyLocalStorage, MyRemoteStorage

    def select_storage():
        return MyLocalStorage() if settings.DEBUG else MyRemoteStorage()

    class MyModel(models.Model):
        my_file = models.FileField(storage=select_storage)

In order to set a storage defined in the `STORAGES` setting you can use `storages`:

    from django.core.files.storage import storages

    def select_storage():
        return storages["mystorage"]

    class MyModel(models.Model):
        upload = models.FileField(storage=select_storage)

Because the callable is evaluated when your models classes are loaded, if you need to override the `STORAGES` setting in tests, you should use a `LazyObject` subclass instead:

    from django.core.files.storage import storages
    from django.utils.functional import LazyObject

    class OtherStorage(LazyObject):
        def _setup(self):
            self._wrapped = storages["mystorage"]

    my_storage = OtherStorage()

    class MyModel(models.Model):
        upload = models.FileField(storage=my_storage)

The `LazyObject` delays the evaluation of the storage until it’s actually needed, allowing `override_settings()` to take effect:

    @override_settings(
        STORAGES={
            "mystorage": {
                "BACKEND": "django.core.files.storage.InMemoryStorage",
            }
        }
    )
    def test_storage():
        model = MyModel()
        assert isinstance(model.upload.storage, InMemoryStorage)