Django文件存储 默认存储系统解析

from django.db import modelsfrom django.core.files.storage import FileSystemStorage fs = FileSystemStorage(location='/media/photos') class Car(models.Model):  ...  photo = models.ImageField(storage=fs)

>>> 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

def _save(self, name, content):  full_path = self.path(name)   # Create any intermediate directories that do not exist.  # Note that there is a race between os.path.exists and os.makedirs:  # if os.makedirs fails with EEXIST, the directory was created  # concurrently, and we can continue normally. Refs #16082.  directory = os.path.dirname(full_path)  if not os.path.exists(directory):    try:      if self.directory_permissions_mode is not None:        # os.makedirs applies the global umask, so we reset it,        # for consistency with file_permissions_mode behavior.        old_umask = os.umask(0)        try:          os.makedirs(directory, self.directory_permissions_mode)        finally:          os.umask(old_umask)      else:        os.makedirs(directory)    except OSError as e:      if e.errno != errno.EEXIST:        raise  if 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)       # 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.        flags = (os.O_WRONLY | os.O_CREAT | os.O_EXCL |             getattr(os, 'O_BINARY', 0))        # The current umask value is masked out by os.open!        fd = os.open(full_path, flags, 0o666)        _file = None        try:          locks.lock(fd, locks.LOCK_EX)          for chunk in content.chunks():            if _file is None:              mode = 'wb' if isinstance(chunk, bytes) else 'wt'              _file = os.fdopen(fd, mode)            _file.write(chunk)        finally:          locks.unlock(fd)          if _file is not None:            _file.close()          else:            os.close(fd)    except OSError as 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 self.file_permissions_mode is not None:    os.chmod(full_path, self.file_permissions_mode)   # Store filenames with forward slashes, even on Windows.  return force_text(name.replace('//', '/'))