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views.py
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views.py
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"""Views."""
from django.core.files import File
from django.core.files.storage import DefaultStorage
from django.http import HttpResponseNotModified
from django.views.generic.base import View
from django.views.generic.detail import BaseDetailView
from django.views.static import was_modified_since
from django_downloadview.files import StorageFile
from django_downloadview.response import DownloadResponse
class DownloadMixin(object):
"""Placeholders and base implementation to create file download views.
The get_file() method is a placeholder, which raises NotImplementedError
in base implementation.
The other methods provide an implementation that use the file object
returned by get_file(), supposing the file is hosted on the local
filesystem.
You may override one or several methods to adapt the implementation to your
use case.
"""
#: Response class to be used in render_to_response().
response_class = DownloadResponse
#: Whether to return the response as attachment or not.
attachment = True
#: Client-side filename, if only file is returned as attachment.
basename = None
def get_file(self):
"""Return a file wrapper instance."""
raise NotImplementedError()
def get_basename(self):
return self.basename
def render_to_response(self, *args, **kwargs):
"""Returns a response with a file as attachment."""
# Respect the If-Modified-Since header.
file_instance = self.get_file()
if_modified_since = self.request.META.get('HTTP_IF_MODIFIED_SINCE',
None)
if if_modified_since is not None:
modification_time = file_instance.modified_time
size = file_instance.size
if not was_modified_since(if_modified_since, modification_time,
size):
content_type = file_instance.content_type
return HttpResponseNotModified(content_type=content_type)
# Return download response.
response_kwargs = {'file_instance': file_instance,
'attachment': self.attachment,
'basename': self.get_basename()}
response_kwargs.update(kwargs)
response = self.response_class(**response_kwargs)
return response
class BaseDownloadView(DownloadMixin, View):
def get(self, request, *args, **kwargs):
"""Handle GET requests: stream a file."""
return self.render_to_response()
class PathDownloadView(BaseDownloadView):
"""Serve a file using filename."""
path = None
"""Server-side name (including path) of the file to serve.
Filename is supposed to be an absolute filename of a file located on the
local filesystem.
"""
path_url_kwarg = 'path'
"""Name of the URL argument that contains path."""
def get_path(self):
"""Return actual path of the file to serve.
Default implementation simply returns view's :py:attr:`path`.
Override this method if you want custom implementation.
As an example, :py:attr:`path` could be relative and your custom
:py:meth:`get_path` implementation makes it absolute.
"""
return self.kwargs.get(self.path_url_kwarg, self.path)
def get_file(self):
"""Use path to return wrapper around file to serve."""
return File(open(self.get_path()))
class StorageDownloadView(PathDownloadView):
"""Serve a file using storage and filename."""
storage = DefaultStorage()
"""Storage the file to serve belongs to."""
path = None # Override docstring.
"""Path to the file to serve relative to storage."""
def get_path(self):
"""Return path of the file to serve, relative to storage.
Default implementation simply returns view's :py:attr:`path`.
Override this method if you want custom implementation.
"""
return super(StorageDownloadView, self).get_path()
def get_file(self):
"""Use path and storage to return wrapper around file to serve."""
return self.storage.open(self.get_path())
class VirtualDownloadView():
"""Serve not-on-disk or generated-on-the-fly file.
Use this class to serve :py:class:`StringIO` files.
"""
file_obj = None
class DownloadView(BaseDownloadView):
"""Download a file from storage and filename."""
#: Server-side name (including path) of the file to serve.
#:
#: If ``storage`` is not None, then the filename will be passed to the
#: storage, else filename is supposed to be an absolute filename of a file
#: located on the local filesystem.
filename = None
#: Storage to use to fetch the file.
#:
#: Defaults to Django's DefaultStorage(), which itself defaults to a
#: FileSystemStorage relative to settings.MEDIA_ROOT.
#:
#: The ``storage`` can be set to None, but you should use one. As an
#: example, storage classes may encapsulate some security checks
#: (FileSystemStorage actually refuses to serve files outside its root
#: location).
storage = DefaultStorage()
def get_file(self):
"""Use filename and storage to return file object to serve."""
if self.storage:
return StorageFile(self.storage, self.filename)
else:
return File(open(self.filename))
class ObjectDownloadView(DownloadMixin, BaseDetailView):
"""Download view for models which contain a FileField.
This class extends BaseDetailView, so you can use its arguments to target
the instance to operate on: slug, slug_kwarg, model, queryset...
See Django's DetailView reference for details.
In addition to BaseDetailView arguments, you can set arguments related to
the file to be downloaded.
The main one is ``file_field``.
The other arguments are provided for convenience, in case your model holds
some (deserialized) metadata about the file, such as its basename, its
modification time, its MIME type... These fields may be particularly handy
if your file storage is not the local filesystem.
"""
#: Name of the model's attribute which contains the file to be streamed.
#: Typically the name of a FileField.
file_field = 'file'
#: Optional name of the model's attribute which contains the basename.
basename_field = None
#: Optional name of the model's attribute which contains the encoding.
encoding_field = None
#: Optional name of the model's attribute which contains the MIME type.
mime_type_field = None
#: Optional name of the model's attribute which contains the charset.
charset_field = None
#: Optional name of the model's attribute which contains the modification
# time.
modification_time_field = None
#: Optional name of the model's attribute which contains the size.
size_field = None
def get_file(self):
"""Return FieldFile instance."""
file_instance = getattr(self.object, self.file_field)
for field in ('encoding', 'mime_type', 'charset', 'modification_time',
'size'):
model_field = getattr(self, '%s_field' % field, False)
if model_field:
value = getattr(self.object, model_field)
setattr(file_instance, field, value)
return file_instance
def get_basename(self):
"""Return client-side filename."""
basename = super(ObjectDownloadView, self).get_basename()
if basename is None:
field = 'basename'
model_field = getattr(self, '%s_field' % field, False)
if model_field:
basename = getattr(self.object, model_field)
return basename