/servicios_web/gae/django-guestbook/src/django/core/files/storage.py
Python | 275 lines | 240 code | 10 blank | 25 comment | 4 complexity | 7d31713aea1eae7a8fb5f2c3103b8d7d MD5 | raw file
- import os
- import errno
- import urlparse
- import itertools
- from datetime import datetime
-
- from django.conf import settings
- from django.core.exceptions import ImproperlyConfigured, SuspiciousOperation
- from django.core.files import locks, File
- from django.core.files.move import file_move_safe
- from django.utils.encoding import force_unicode
- from django.utils.functional import LazyObject
- from django.utils.importlib import import_module
- from django.utils.text import get_valid_filename
- from django.utils._os import safe_join
-
- __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.
- """
- dir_name, file_name = os.path.split(name)
- file_root, file_ext = os.path.splitext(file_name)
- # If the filename already exists, add an underscore and a number (before
- # the file extension, if one exists) to the filename until the generated
- # filename doesn't exist.
- count = itertools.count(1)
- while self.exists(name):
- # file_ext includes the dot.
- name = os.path.join(dir_name, "%s_%s%s" % (file_root, count.next(), file_ext))
-
- 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()
-
- def accessed_time(self, name):
- """
- Returns the last accessed time (as datetime object) of the file
- specified by name.
- """
- raise NotImplementedError()
-
- def created_time(self, name):
- """
- Returns the creation time (as datetime object) of the file
- specified by name.
- """
- raise NotImplementedError()
-
- def modified_time(self, name):
- """
- Returns the last modified time (as datetime object) of the file
- specified by name.
- """
- raise NotImplementedError()
-
- class FileSystemStorage(Storage):
- """
- Standard filesystem storage
- """
-
- def __init__(self, location=None, base_url=None):
- if location is None:
- location = settings.MEDIA_ROOT
- if base_url is None:
- 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 accessed_time(self, name):
- return datetime.fromtimestamp(os.path.getatime(self.path(name)))
-
- def created_time(self, name):
- return datetime.fromtimestamp(os.path.getctime(self.path(name)))
-
- def modified_time(self, name):
- return datetime.fromtimestamp(os.path.getmtime(self.path(name)))
-
- def get_storage_class(import_path=None):
- if import_path is None:
- import_path = settings.DEFAULT_FILE_STORAGE
- 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(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))
-
- class DefaultStorage(LazyObject):
- def _setup(self):
- self._wrapped = get_storage_class()()
-
- default_storage = DefaultStorage()