+
−import os
+
−import errno
+
−import urlparse
+
−
+
−from django.conf import settings
+
−from django.core.exceptions import ImproperlyConfigured, SuspiciousOperation
+
−from django.utils.encoding import force_unicode
+
−from django.utils.text import get_valid_filename
+
−from django.utils._os import safe_join
+
−from django.core.files import locks, File
+
−from django.core.files.move import file_move_safe
+
−
+
−__all__ = ('Storage', 'FileSystemStorage', 'DefaultStorage', 'default_storage')
+
−
+
−class Storage(object):
+
−    """
+
−    A base storage class, providing some default behaviors that all other
+
−    storage systems can inherit or override, as necessary.
+
−    """
+
−
+
−    # The following methods represent a public interface to private methods.
+
−    # These shouldn't be overridden by subclasses unless absolutely necessary.
+
−
+
−    def open(self, name, mode='rb', mixin=None):
+
−        """
+
−        Retrieves the specified file from storage, using the optional mixin
+
−        class to customize what features are available on the File returned.
+
−        """
+
−        file = self._open(name, mode)
+
−        if mixin:
+
−            # Add the mixin as a parent class of the File returned from storage.
+
−            file.__class__ = type(mixin.__name__, (mixin, file.__class__), {})
+
−        return file
+
−
+
−    def save(self, name, content):
+
−        """
+
−        Saves new content to the file specified by name. The content should be a
+
−        proper File object, ready to be read from the beginning.
+
−        """
+
−        # Get the proper name for the file, as it will actually be saved.
+
−        if name is None:
+
−            name = content.name
+
−        
+
−        name = self.get_available_name(name)
+
−        name = self._save(name, content)
+
−
+
−        # Store filenames with forward slashes, even on Windows
+
−        return force_unicode(name.replace('\\', '/'))
+
−
+
−    # These methods are part of the public API, with default implementations.
+
−
+
−    def get_valid_name(self, name):
+
−        """
+
−        Returns a filename, based on the provided filename, that's suitable for
+
−        use in the target storage system.
+
−        """
+
−        return get_valid_filename(name)
+
−
+
−    def get_available_name(self, name):
+
−        """
+
−        Returns a filename that's free on the target storage system, and
+
−        available for new content to be written to.
+
−        """
+
−        # If the filename already exists, keep adding an underscore to the name
+
−        # of the file until the filename doesn't exist.
+
−        while self.exists(name):
+
−            try:
+
−                dot_index = name.rindex('.')
+
−            except ValueError: # filename has no dot
+
−                name += '_'
+
−            else:
+
−                name = name[:dot_index] + '_' + name[dot_index:]
+
−        return name
+
−
+
−    def path(self, name):
+
−        """
+
−        Returns a local filesystem path where the file can be retrieved using
+
−        Python's built-in open() function. Storage systems that can't be
+
−        accessed using open() should *not* implement this method.
+
−        """
+
−        raise NotImplementedError("This backend doesn't support absolute paths.")
+
−
+
−    # The following methods form the public API for storage systems, but with
+
−    # no default implementations. Subclasses must implement *all* of these.
+
−
+
−    def delete(self, name):
+
−        """
+
−        Deletes the specified file from the storage system.
+
−        """
+
−        raise NotImplementedError()
+
−
+
−    def exists(self, name):
+
−        """
+
−        Returns True if a file referened by the given name already exists in the
+
−        storage system, or False if the name is available for a new file.
+
−        """
+
−        raise NotImplementedError()
+
−
+
−    def listdir(self, path):
+
−        """
+
−        Lists the contents of the specified path, returning a 2-tuple of lists;
+
−        the first item being directories, the second item being files.
+
−        """
+
−        raise NotImplementedError()
+
−
+
−    def size(self, name):
+
−        """
+
−        Returns the total size, in bytes, of the file specified by name.
+
−        """
+
−        raise NotImplementedError()
+
−
+
−    def url(self, name):
+
−        """
+
−        Returns an absolute URL where the file's contents can be accessed
+
−        directly by a web browser.
+
−        """
+
−        raise NotImplementedError()
+
−
+
−class FileSystemStorage(Storage):
+
−    """
+
−    Standard filesystem storage
+
−    """
+
−
+
−    def __init__(self, location=settings.MEDIA_ROOT, base_url=settings.MEDIA_URL):
+
−        self.location = os.path.abspath(location)
+
−        self.base_url = base_url
+
−
+
−    def _open(self, name, mode='rb'):
+
−        return File(open(self.path(name), mode))
+
−
+
−    def _save(self, name, content):
+
−        full_path = self.path(name)
+
−
+
−        directory = os.path.dirname(full_path)
+
−        if not os.path.exists(directory):
+
−            os.makedirs(directory)
+
−        elif not os.path.isdir(directory):
+
−            raise IOError("%s exists and is not a directory." % directory)
+
−
+
−        # There's a potential race condition between get_available_name and
+
−        # saving the file; it's possible that two threads might return the
+
−        # same name, at which point all sorts of fun happens. So we need to
+
−        # try to create the file, but if it already exists we have to go back
+
−        # to get_available_name() and try again.
+
−
+
−        while True:
+
−            try:
+
−                # This file has a file path that we can move.
+
−                if hasattr(content, 'temporary_file_path'):
+
−                    file_move_safe(content.temporary_file_path(), full_path)
+
−                    content.close()
+
−
+
−                # This is a normal uploadedfile that we can stream.
+
−                else:
+
−                    # This fun binary flag incantation makes os.open throw an
+
−                    # OSError if the file already exists before we open it.
+
−                    fd = os.open(full_path, os.O_WRONLY | os.O_CREAT | os.O_EXCL | getattr(os, 'O_BINARY', 0))
+
−                    try:
+
−                        locks.lock(fd, locks.LOCK_EX)
+
−                        for chunk in content.chunks():
+
−                            os.write(fd, chunk)
+
−                    finally:
+
−                        locks.unlock(fd)
+
−                        os.close(fd)
+
−            except OSError, e:
+
−                if e.errno == errno.EEXIST:
+
−                    # Ooops, the file exists. We need a new file name.
+
−                    name = self.get_available_name(name)
+
−                    full_path = self.path(name)
+
−                else:
+
−                    raise
+
−            else:
+
−                # OK, the file save worked. Break out of the loop.
+
−                break
+
−        
+
−        if settings.FILE_UPLOAD_PERMISSIONS is not None:
+
−            os.chmod(full_path, settings.FILE_UPLOAD_PERMISSIONS)
+
−        
+
−        return name
+
−
+
−    def delete(self, name):
+
−        name = self.path(name)
+
−        # If the file exists, delete it from the filesystem.
+
−        if os.path.exists(name):
+
−            os.remove(name)
+
−
+
−    def exists(self, name):
+
−        return os.path.exists(self.path(name))
+
−
+
−    def listdir(self, path):
+
−        path = self.path(path)
+
−        directories, files = [], []
+
−        for entry in os.listdir(path):
+
−            if os.path.isdir(os.path.join(path, entry)):
+
−                directories.append(entry)
+
−            else:
+
−                files.append(entry)
+
−        return directories, files
+
−
+
−    def path(self, name):
+
−        try:
+
−            path = safe_join(self.location, name)
+
−        except ValueError:
+
−            raise SuspiciousOperation("Attempted access to '%s' denied." % name)
+
−        return os.path.normpath(path)
+
−
+
−    def size(self, name):
+
−        return os.path.getsize(self.path(name))
+
−
+
−    def url(self, name):
+
−        if self.base_url is None:
+
−            raise ValueError("This file is not accessible via a URL.")
+
−        return urlparse.urljoin(self.base_url, name).replace('\\', '/')
+
−
+
−def get_storage_class(import_path):
+
−    try:
+
−        dot = import_path.rindex('.')
+
−    except ValueError:
+
−        raise ImproperlyConfigured("%s isn't a storage module." % import_path)
+
−    module, classname = import_path[:dot], import_path[dot+1:]
+
−    try:
+
−        mod = __import__(module, {}, {}, [''])
+
−    except ImportError, e:
+
−        raise ImproperlyConfigured('Error importing storage module %s: "%s"' % (module, e))
+
−    try:
+
−        return getattr(mod, classname)
+
−    except AttributeError:
+
−        raise ImproperlyConfigured('Storage module "%s" does not define a "%s" class.' % (module, classname))
+
−
+
−DefaultStorage = get_storage_class(settings.DEFAULT_FILE_STORAGE)
+
−default_storage = DefaultStorage()