Mengelola berkas

This document describes Django’s file access APIs for files such as those uploaded by a user. The lower level APIs are general enough that you could use them for other purposes. If you want to handle “static files” (JS, CSS, etc.), see Mengelola berkas statis (sebagai contoh gambar, JavaScript, CSS).

By default, Django stores files locally, using the MEDIA_ROOT and MEDIA_URL settings. The examples below assume that you’re using these defaults.

However, Django provides ways to write custom file storage systems that allow you to completely customize where and how Django stores files. The second half of this document describes how these storage systems work.

Menggunakan berkas dalam model

When you use a FileField or ImageField, Django provides a set of APIs you can use to deal with that file.

Consider the following model, using an ImageField to store a photo:

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')

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: chevy.jpg>
>>> car.photo.name
'cars/chevy.jpg'
>>> car.photo.path
'/media/cars/chevy.jpg'
>>> car.photo.url
'http://media.example.com/cars/chevy.jpg'

This object – car.photo in the example – is a File object, which means it has all the methods and attributes described below.

Catatan

The file is saved as part of saving the model in the database, so the actual file name used on disk cannot be relied on until after the model has been saved.

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 = 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

Obyek File

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

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

Jika anda butuh membangun sebuah File anda sendiri, cara termudah adalah membuat satu menggunakan Python obyek file siap-pakai:

>>> 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:

IOError: [Errno 24] Too many open files

Penyimpanan berkas

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 given by the DEFAULT_FILE_STORAGE setting; if you don’t explicitly provide a storage system, this is the one that will be used.

See below for details of the built-in default file storage system, and see Menulis sistem penyimpanan disesuaikan for information on writing your own file storage system.

Obyek penyimpanan

Meskipun kebanyakan waktu anda akan ingin menggunakan sebuah obyek File (yang menunjukkan ke penyimpanan sesuai untuk berkas itu), anda dapat menggunakan sistem penyimpanan berkas langsung. Anda dapat membuat sebuah instance dari beberapa kelas penyimpanan berkas penyesuaian, atau – sering lebih berguna – anda dapat menggunakan sistem penyimpanan awalan global:

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

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

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

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

Lihat File storage API untuk API penyimpanan berkas.

Kelas penyimpanan sistem berkas siap-pakai

Django dibekali dengan kelas django.core.files.storage.FileSystemStorage yang menerapkan penyimpanan berkas sistem berkas lokal.

Sebagai contoh, kode berikut akan menyimpan berkas-berkas terunggah dibawah /media/photos meskipun dari apa pengaturan MEDIA_ROOT:

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

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.