#35045: Add a PersistedTemporaryFileUploadHandler for file upload
-------------------------------------+-------------------------------------
Reporter: | Owner: nobody
DninoAdnane |
Type: New | Status: new
feature |
Component: File | Version: dev
uploads/storage | Keywords: django,
Severity: Normal | uploadhandler, uploadedfile, core,
| TempraryFileUploadHandler,
Triage Stage: | PersistedTemporaryFileUploadHandler
Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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Using the **PersistedTemporaryFileUploadHandler** upload handler, Django
will write the uploaded file to a temporary file stored in your system's
temporary directory, as the **TemporaryFileUploadHandler** already do.
However, the file this time will not be suppressed after your first read,
and will persist until you delete it.
**PersistedTemporaryFileUploadHandler** class inherit from the
**TemporaryFileUploadHandler** class.
=== Use cases
- One use case that I personally faced is having many threads reading from
the same uploaded file. When one of the threads reads the file content,
the file is automatically deleted, and so became unavailable for the other
threads.
- Another use case was find in a
[https://stackoverflow.com/questions/11835274/django-control-time-of-
temporaryuploadedfile-life/76021825 stack overflow] question, where a user
was looking for a way to control the life time of the uploaded file.
=== Implementation
== PersistedTemporaryUploadedFile
{{{
#!python
class PersistedTemporaryUploadedFile(UploadedFile):
"""
A file uploaded to a temporary location (i.e. stream-to-disk).
The file does not get deleted after a first read from disk
"""
def __init__(self, name, content_type, size, charset,
content_type_extra=None):
_, ext = os.path.splitext(name)
file = tempfile.NamedTemporaryFile(
suffix=".upload" + ext,
dir=settings.FILE_UPLOAD_TEMP_DIR,
delete=False, # forbid the file from being deleted
automatically
)
super().__init__(file, name, content_type, size, charset,
content_type_extra)
def temporary_file_path(self):
"""Return the full path of this file."""
return self.file.name
def close(self):
try:
return self.file.close()
except FileNotFoundError:
# The file was moved or deleted before the tempfile could
unlink
# it. Still sets self.file.close_called and calls
# self.file.file.close() before the exception.
pass
}}}
== PersistedTemporaryFileUploadHandler
{{{
#!python
class PersistedTemporaryFileUploadHandler(TemporaryFileUploadHandler):
"""
Upload handler that streams data into a temporary file.
The file does not get deleted after a first read and should
be closed after use.
"""
def new_file(self, *args, **kwargs):
"""
Create the file object to append to as data is coming in.
"""
super().new_file(*args, **kwargs)
self.file = PersistedTemporaryUploadedFile(
self.file_name, self.content_type, 0, self.charset,
self.content_type_extra
)
}}}
The upload handler should after be defined in the ''setting'':
**FILE_UPLOAD_HANDLERS** setting:
**''django.core.files.uploadhandler.PersistedTemporaryFileUploadHandler''**
=== Tests
{{{
#!python
def test_upload_temporary_file_handler(self):
with tempfile.NamedTemporaryFile() as temp_file:
temp_file.write(b"a")
temp_file.seek(0)
response = self.client.post("/temp_file/", {"file":
temp_file})
temp_path = response.json()["temp_path"]
# File get deleted after first access
self.assertIs(os.path.exists(temp_path), False)
def test_upload_persisted_temporary_file_handler(self):
with tempfile.NamedTemporaryFile() as temp_file:
temp_file.write(b"a")
temp_file.seek(0)
response = self.client.post(
"/temp_file/persisted_file/", {"file": temp_file}
)
temp_path = response.json()["temp_path"]
# File does not get deleted after first access
self.assertIs(os.path.exists(temp_path), True)
os.remove(temp_path)
self.assertIs(os.path.exists(temp_path), False)
}}}
=== N.B
Even thought it may be easy to forbid the temporary file from being
deleted, I think it's a necessary feature or class to have withing the
framework as it's a behavior that I would naturally consider available in
such a great framework.
--
Ticket URL: <https://code.djangoproject.com/ticket/35045>
Django <https://code.djangoproject.com/>
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