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Diffstat (limited to 'webapp/django/core/files/storage.py')
| -rw-r--r-- | webapp/django/core/files/storage.py | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/webapp/django/core/files/storage.py b/webapp/django/core/files/storage.py new file mode 100644 index 0000000000..30d9be9f00 --- /dev/null +++ b/webapp/django/core/files/storage.py @@ -0,0 +1,224 @@ +import os +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: + # Ooops, we need a new file name. + name = self.get_available_name(name) + full_path = self.path(name) + else: + # OK, the file save worked. Break out of the loop. + break + + 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() |