File オブジェクト¶

File クラス¶

class File(file_object, name=None)¶

File クラスは、Python の file object に Django 特有の追加機能を付け加えた薄いラッパーです。内部的でファイルを表現する必要がある場合には、Django はこのクラスを使います。

File オブジェクトには次の属性とメソッドを持ちます。

name¶

MEDIA_ROOT からの相対パスを含むファイル名です。

size¶

bytes で表されたファイルサイズ。

file¶

このクラスがラッピングしている、素の file object クラスです。

この属性をサブクラスで扱う場合には注意が必要です。

ContentFile や FieldFile など File のサブクラスは、この属性を Python の file object 以外のオブジェクトに置き換えることがあります。このような場合には、この属性自体は File のサブクラスであるかもしれません (が、同じサブクラスとは限りません)。そのため、可能な限り、サブクラスの file 属性ではなく、サブクラス自身が持つ属性やメソッドを使用するようにしてください。

mode¶

ファイルの読み込み/書き込みのモードです。

open(mode=None)¶

Open or reopen the file (which also does File.seek(0)). The mode argument allows the same values as Python's built-in open().

When reopening a file, mode will override whatever mode the file was originally opened with; None means to reopen with the original mode.

It can be used as a context manager, e.g. with file.open() as f:.

__iter__()¶

Iterate over the file yielding one line at a time.

chunks(chunk_size=None)¶

Iterate over the file yielding "chunks" of a given size. chunk_size defaults to 64 KB.

This is especially useful with very large files since it allows them to be streamed off disk and avoids storing the whole file in memory.

multiple_chunks(chunk_size=None)¶

Returns True if the file is large enough to require multiple chunks to access all of its content give some chunk_size.

close()¶

Close the file.

In addition to the listed methods, File exposes the following attributes and methods of its file object: encoding, fileno, flush, isatty, newlines, read, readinto, readline, readlines, seek, tell, truncate, write, writelines, readable(), writable(), and seekable().

ContentFile クラス¶

class ContentFile(content, name=None)¶

The ContentFile class inherits from File, but unlike File it operates on string content (bytes also supported), rather than an actual file. For example:

from django.core.files.base import ContentFile

f1 = ContentFile("esta frase está en español")
f2 = ContentFile(b"these are bytes")

ImageFile クラス¶

class ImageFile(file_object, name=None)¶

Django provides a built-in class specifically for images. django.core.files.images.ImageFile inherits all the attributes and methods of File, and additionally provides the following:

width¶

Width of the image in pixels.

height¶

Height of the image in pixels.

Additional methods on files attached to objects¶

Any File that is associated with an object (as with Car.photo, below) will also have a couple of extra methods:

File.save(name, content, save=True)¶

Saves a new file with the file name and contents provided. This will not replace the existing file, but will create a new file and update the object to point to it. If save is True, the model's save() method will be called once the file is saved. That is, these two lines:

>>> car.photo.save("myphoto.jpg", content, save=False)
>>> car.save()

are equivalent to:

>>> car.photo.save("myphoto.jpg", content, save=True)

Note that the content argument must be an instance of either File or of a subclass of File, such as ContentFile.

File.delete(save=True)¶

Removes the file from the model instance and deletes the underlying file. If save is True, the model's save() method will be called once the file is deleted.