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