django1/django/core/files/uploadhandler.py

216 lines
6.8 KiB
Python

"""
Base file upload handler classes, and the built-in concrete subclasses
"""
from __future__ import unicode_literals
from io import BytesIO
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured
from django.core.files.uploadedfile import TemporaryUploadedFile, InMemoryUploadedFile
from django.utils import importlib
__all__ = ['UploadFileException','StopUpload', 'SkipFile', 'FileUploadHandler',
'TemporaryFileUploadHandler', 'MemoryFileUploadHandler',
'load_handler', 'StopFutureHandlers']
class UploadFileException(Exception):
"""
Any error having to do with uploading files.
"""
pass
class StopUpload(UploadFileException):
"""
This exception is raised when an upload must abort.
"""
def __init__(self, connection_reset=False):
"""
If ``connection_reset`` is ``True``, Django knows will halt the upload
without consuming the rest of the upload. This will cause the browser to
show a "connection reset" error.
"""
self.connection_reset = connection_reset
def __unicode__(self):
if self.connection_reset:
return 'StopUpload: Halt current upload.'
else:
return 'StopUpload: Consume request data, then halt.'
class SkipFile(UploadFileException):
"""
This exception is raised by an upload handler that wants to skip a given file.
"""
pass
class StopFutureHandlers(UploadFileException):
"""
Upload handers that have handled a file and do not want future handlers to
run should raise this exception instead of returning None.
"""
pass
class FileUploadHandler(object):
"""
Base class for streaming upload handlers.
"""
chunk_size = 64 * 2 ** 10 #: The default chunk size is 64 KB.
def __init__(self, request=None):
self.file_name = None
self.content_type = None
self.content_length = None
self.charset = None
self.request = request
def handle_raw_input(self, input_data, META, content_length, boundary, encoding=None):
"""
Handle the raw input from the client.
Parameters:
:input_data:
An object that supports reading via .read().
:META:
``request.META``.
:content_length:
The (integer) value of the Content-Length header from the
client.
:boundary: The boundary from the Content-Type header. Be sure to
prepend two '--'.
"""
pass
def new_file(self, field_name, file_name, content_type, content_length, charset=None):
"""
Signal that a new file has been started.
Warning: As with any data from the client, you should not trust
content_length (and sometimes won't even get it).
"""
self.field_name = field_name
self.file_name = file_name
self.content_type = content_type
self.content_length = content_length
self.charset = charset
def receive_data_chunk(self, raw_data, start):
"""
Receive data from the streamed upload parser. ``start`` is the position
in the file of the chunk.
"""
raise NotImplementedError()
def file_complete(self, file_size):
"""
Signal that a file has completed. File size corresponds to the actual
size accumulated by all the chunks.
Subclasses should return a valid ``UploadedFile`` object.
"""
raise NotImplementedError()
def upload_complete(self):
"""
Signal that the upload is complete. Subclasses should perform cleanup
that is necessary for this handler.
"""
pass
class TemporaryFileUploadHandler(FileUploadHandler):
"""
Upload handler that streams data into a temporary file.
"""
def __init__(self, *args, **kwargs):
super(TemporaryFileUploadHandler, self).__init__(*args, **kwargs)
def new_file(self, file_name, *args, **kwargs):
"""
Create the file object to append to as data is coming in.
"""
super(TemporaryFileUploadHandler, self).new_file(file_name, *args, **kwargs)
self.file = TemporaryUploadedFile(self.file_name, self.content_type, 0, self.charset)
def receive_data_chunk(self, raw_data, start):
self.file.write(raw_data)
def file_complete(self, file_size):
self.file.seek(0)
self.file.size = file_size
return self.file
class MemoryFileUploadHandler(FileUploadHandler):
"""
File upload handler to stream uploads into memory (used for small files).
"""
def handle_raw_input(self, input_data, META, content_length, boundary, encoding=None):
"""
Use the content_length to signal whether or not this handler should be in use.
"""
# Check the content-length header to see if we should
# If the post is too large, we cannot use the Memory handler.
if content_length > settings.FILE_UPLOAD_MAX_MEMORY_SIZE:
self.activated = False
else:
self.activated = True
def new_file(self, *args, **kwargs):
super(MemoryFileUploadHandler, self).new_file(*args, **kwargs)
if self.activated:
self.file = BytesIO()
raise StopFutureHandlers()
def receive_data_chunk(self, raw_data, start):
"""
Add the data to the BytesIO file.
"""
if self.activated:
self.file.write(raw_data)
else:
return raw_data
def file_complete(self, file_size):
"""
Return a file object if we're activated.
"""
if not self.activated:
return
self.file.seek(0)
return InMemoryUploadedFile(
file = self.file,
field_name = self.field_name,
name = self.file_name,
content_type = self.content_type,
size = file_size,
charset = self.charset
)
def load_handler(path, *args, **kwargs):
"""
Given a path to a handler, return an instance of that handler.
E.g.::
>>> load_handler('django.core.files.uploadhandler.TemporaryFileUploadHandler', request)
<TemporaryFileUploadHandler object at 0x...>
"""
i = path.rfind('.')
module, attr = path[:i], path[i+1:]
try:
mod = importlib.import_module(module)
except ImportError as e:
raise ImproperlyConfigured('Error importing upload handler module %s: "%s"' % (module, e))
except ValueError:
raise ImproperlyConfigured('Error importing upload handler module.'
'Is FILE_UPLOAD_HANDLERS a correctly defined list or tuple?')
try:
cls = getattr(mod, attr)
except AttributeError:
raise ImproperlyConfigured('Module "%s" does not define a "%s" upload handler backend' % (module, attr))
return cls(*args, **kwargs)