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Source code for django.core.files.uploadhandler

"""
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.files.uploadedfile import TemporaryUploadedFile, InMemoryUploadedFile
from django.utils.encoding import python_2_unicode_compatible
from django.utils.module_loading import import_string

__all__ = [
    'UploadFileException', 'StopUpload', 'SkipFile', 'FileUploadHandler',
    'TemporaryFileUploadHandler', 'MemoryFileUploadHandler', 'load_handler',
    'StopFutureHandlers'
]


class UploadFileException(Exception):
    """
    Any error having to do with uploading files.
    """
    pass


@python_2_unicode_compatible
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 __str__(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


[docs]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.content_type_extra = None self.request = request
[docs] 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
[docs] def new_file(self, field_name, file_name, content_type, content_length, charset=None, content_type_extra=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 self.content_type_extra = content_type_extra
[docs] 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('subclasses of FileUploadHandler must provide a receive_data_chunk() method')
[docs] 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('subclasses of FileUploadHandler must provide a file_complete() method')
[docs] def upload_complete(self): """ Signal that the upload is complete. Subclasses should perform cleanup that is necessary for this handler. """ pass
[docs]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, self.content_type_extra) 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
[docs]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, content_type_extra=self.content_type_extra )
def load_handler(path, *args, **kwargs): """ Given a path to a handler, return an instance of that handler. E.g.:: >>> from django.http import HttpRequest >>> request = HttpRequest() >>> load_handler('django.core.files.uploadhandler.TemporaryFileUploadHandler', request) <TemporaryFileUploadHandler object at 0x...> """ return import_string(path)(*args, **kwargs)
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