337 lines
13 KiB
Python
337 lines
13 KiB
Python
import errno
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import os
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import warnings
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from datetime import datetime
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from inspect import getargspec
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from django.conf import settings
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from django.core.exceptions import SuspiciousFileOperation
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from django.core.files import File, locks
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from django.core.files.move import file_move_safe
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from django.utils._os import abspathu, safe_join
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from django.utils.crypto import get_random_string
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from django.utils.deconstruct import deconstructible
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from django.utils.deprecation import RemovedInDjango20Warning
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from django.utils.encoding import filepath_to_uri, force_text
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from django.utils.functional import LazyObject
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from django.utils.module_loading import import_string
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from django.utils.six.moves.urllib.parse import urljoin
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from django.utils.text import get_valid_filename
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__all__ = ('Storage', 'FileSystemStorage', 'DefaultStorage', 'default_storage')
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class Storage(object):
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"""
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A base storage class, providing some default behaviors that all other
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storage systems can inherit or override, as necessary.
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"""
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# The following methods represent a public interface to private methods.
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# These shouldn't be overridden by subclasses unless absolutely necessary.
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def open(self, name, mode='rb'):
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"""
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Retrieves the specified file from storage.
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"""
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return self._open(name, mode)
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def save(self, name, content, max_length=None):
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"""
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Saves new content to the file specified by name. The content should be
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a proper File object or any python file-like object, ready to be read
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from the beginning.
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"""
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# Get the proper name for the file, as it will actually be saved.
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if name is None:
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name = content.name
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if not hasattr(content, 'chunks'):
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content = File(content)
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args, varargs, varkw, defaults = getargspec(self.get_available_name)
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if 'max_length' in args:
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name = self.get_available_name(name, max_length=max_length)
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else:
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warnings.warn(
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'Backwards compatibility for storage backends without '
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'support for the `max_length` argument in '
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'Storage.get_available_name() will be removed in Django 2.0.',
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RemovedInDjango20Warning, stacklevel=2
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)
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name = self.get_available_name(name)
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name = self._save(name, content)
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# Store filenames with forward slashes, even on Windows
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return force_text(name.replace('\\', '/'))
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# These methods are part of the public API, with default implementations.
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def get_valid_name(self, name):
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"""
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Returns a filename, based on the provided filename, that's suitable for
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use in the target storage system.
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"""
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return get_valid_filename(name)
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def get_available_name(self, name, max_length=None):
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"""
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Returns a filename that's free on the target storage system, and
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available for new content to be written to.
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"""
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dir_name, file_name = os.path.split(name)
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file_root, file_ext = os.path.splitext(file_name)
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# If the filename already exists, add an underscore and a random 7
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# character alphanumeric string (before the file extension, if one
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# exists) to the filename until the generated filename doesn't exist.
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# Truncate original name if required, so the new filename does not
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# exceed the max_length.
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while self.exists(name) or (max_length and len(name) > max_length):
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# file_ext includes the dot.
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name = os.path.join(dir_name, "%s_%s%s" % (file_root, get_random_string(7), file_ext))
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if max_length is None:
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continue
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# Truncate file_root if max_length exceeded.
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truncation = len(name) - max_length
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if truncation > 0:
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file_root = file_root[:-truncation]
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# Entire file_root was truncated in attempt to find an available filename.
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if not file_root:
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raise SuspiciousFileOperation(
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'Storage can not find an available filename for "%s". '
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'Please make sure that the corresponding file field '
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'allows sufficient "max_length".' % name
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)
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name = os.path.join(dir_name, "%s_%s%s" % (file_root, get_random_string(7), file_ext))
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return name
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def path(self, name):
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"""
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Returns a local filesystem path where the file can be retrieved using
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Python's built-in open() function. Storage systems that can't be
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accessed using open() should *not* implement this method.
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"""
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raise NotImplementedError("This backend doesn't support absolute paths.")
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# The following methods form the public API for storage systems, but with
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# no default implementations. Subclasses must implement *all* of these.
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def delete(self, name):
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"""
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Deletes the specified file from the storage system.
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"""
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raise NotImplementedError('subclasses of Storage must provide a delete() method')
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def exists(self, name):
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"""
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Returns True if a file referenced by the given name already exists in the
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storage system, or False if the name is available for a new file.
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"""
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raise NotImplementedError('subclasses of Storage must provide an exists() method')
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def listdir(self, path):
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"""
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Lists the contents of the specified path, returning a 2-tuple of lists;
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the first item being directories, the second item being files.
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"""
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raise NotImplementedError('subclasses of Storage must provide a listdir() method')
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def size(self, name):
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"""
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Returns the total size, in bytes, of the file specified by name.
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"""
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raise NotImplementedError('subclasses of Storage must provide a size() method')
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def url(self, name):
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"""
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Returns an absolute URL where the file's contents can be accessed
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directly by a Web browser.
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"""
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raise NotImplementedError('subclasses of Storage must provide a url() method')
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def accessed_time(self, name):
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"""
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Returns the last accessed time (as datetime object) of the file
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specified by name.
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"""
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raise NotImplementedError('subclasses of Storage must provide an accessed_time() method')
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def created_time(self, name):
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"""
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Returns the creation time (as datetime object) of the file
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specified by name.
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"""
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raise NotImplementedError('subclasses of Storage must provide a created_time() method')
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def modified_time(self, name):
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"""
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Returns the last modified time (as datetime object) of the file
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specified by name.
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"""
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raise NotImplementedError('subclasses of Storage must provide a modified_time() method')
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@deconstructible
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class FileSystemStorage(Storage):
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"""
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Standard filesystem storage
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"""
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def __init__(self, location=None, base_url=None, file_permissions_mode=None,
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directory_permissions_mode=None):
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if location is None:
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location = settings.MEDIA_ROOT
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self.base_location = location
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self.location = abspathu(self.base_location)
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if base_url is None:
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base_url = settings.MEDIA_URL
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elif not base_url.endswith('/'):
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base_url += '/'
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self.base_url = base_url
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self.file_permissions_mode = (
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file_permissions_mode if file_permissions_mode is not None
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else settings.FILE_UPLOAD_PERMISSIONS
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)
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self.directory_permissions_mode = (
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directory_permissions_mode if directory_permissions_mode is not None
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else settings.FILE_UPLOAD_DIRECTORY_PERMISSIONS
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)
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def _open(self, name, mode='rb'):
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return File(open(self.path(name), mode))
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def _save(self, name, content):
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full_path = self.path(name)
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# Create any intermediate directories that do not exist.
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# Note that there is a race between os.path.exists and os.makedirs:
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# if os.makedirs fails with EEXIST, the directory was created
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# concurrently, and we can continue normally. Refs #16082.
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directory = os.path.dirname(full_path)
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if not os.path.exists(directory):
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try:
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if self.directory_permissions_mode is not None:
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# os.makedirs applies the global umask, so we reset it,
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# for consistency with file_permissions_mode behavior.
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old_umask = os.umask(0)
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try:
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os.makedirs(directory, self.directory_permissions_mode)
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finally:
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os.umask(old_umask)
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else:
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os.makedirs(directory)
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except OSError as e:
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if e.errno != errno.EEXIST:
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raise
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if not os.path.isdir(directory):
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raise IOError("%s exists and is not a directory." % directory)
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# There's a potential race condition between get_available_name and
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# saving the file; it's possible that two threads might return the
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# same name, at which point all sorts of fun happens. So we need to
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# try to create the file, but if it already exists we have to go back
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# to get_available_name() and try again.
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while True:
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try:
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# This file has a file path that we can move.
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if hasattr(content, 'temporary_file_path'):
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file_move_safe(content.temporary_file_path(), full_path)
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# This is a normal uploadedfile that we can stream.
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else:
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# This fun binary flag incantation makes os.open throw an
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# OSError if the file already exists before we open it.
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flags = (os.O_WRONLY | os.O_CREAT | os.O_EXCL |
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getattr(os, 'O_BINARY', 0))
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# The current umask value is masked out by os.open!
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fd = os.open(full_path, flags, 0o666)
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_file = None
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try:
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locks.lock(fd, locks.LOCK_EX)
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for chunk in content.chunks():
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if _file is None:
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mode = 'wb' if isinstance(chunk, bytes) else 'wt'
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_file = os.fdopen(fd, mode)
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_file.write(chunk)
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finally:
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locks.unlock(fd)
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if _file is not None:
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_file.close()
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else:
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os.close(fd)
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except OSError as e:
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if e.errno == errno.EEXIST:
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# Ooops, the file exists. We need a new file name.
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name = self.get_available_name(name)
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full_path = self.path(name)
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else:
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raise
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else:
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# OK, the file save worked. Break out of the loop.
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break
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if self.file_permissions_mode is not None:
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os.chmod(full_path, self.file_permissions_mode)
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return name
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def delete(self, name):
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assert name, "The name argument is not allowed to be empty."
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name = self.path(name)
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# If the file exists, delete it from the filesystem.
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# Note that there is a race between os.path.exists and os.remove:
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# if os.remove fails with ENOENT, the file was removed
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# concurrently, and we can continue normally.
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if os.path.exists(name):
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try:
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os.remove(name)
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except OSError as e:
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if e.errno != errno.ENOENT:
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raise
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def exists(self, name):
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return os.path.exists(self.path(name))
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def listdir(self, path):
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path = self.path(path)
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directories, files = [], []
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for entry in os.listdir(path):
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if os.path.isdir(os.path.join(path, entry)):
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directories.append(entry)
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else:
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files.append(entry)
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return directories, files
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def path(self, name):
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return safe_join(self.location, name)
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def size(self, name):
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return os.path.getsize(self.path(name))
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def url(self, name):
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if self.base_url is None:
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raise ValueError("This file is not accessible via a URL.")
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return urljoin(self.base_url, filepath_to_uri(name))
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def accessed_time(self, name):
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return datetime.fromtimestamp(os.path.getatime(self.path(name)))
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def created_time(self, name):
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return datetime.fromtimestamp(os.path.getctime(self.path(name)))
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def modified_time(self, name):
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return datetime.fromtimestamp(os.path.getmtime(self.path(name)))
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def get_storage_class(import_path=None):
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return import_string(import_path or settings.DEFAULT_FILE_STORAGE)
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class DefaultStorage(LazyObject):
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def _setup(self):
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self._wrapped = get_storage_class()()
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default_storage = DefaultStorage()
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