django check if the uploaded file is a zip file

Question

I have a handler for a POST method in Django which receives an uploaded file. What I would like to do is verify that the file is a valid zip file before proceeding.

So, I have:

@login_required(login_url="login/")
def upload(request):
    if request.method == 'POST' and request.FILES['upload_file']:
        uploaded_file = request.FILES['upload_file']
        print type(uploaded_file)

    return render(request, 'upload.html', {'context': RequestContext(request)})

Now at this point uploaded_file is of type <class 'django.core.files.uploadedfile.InMemoryUploadedFile'>. My question is what would be the best way to verify that this is a valid archive? Do I need to save it to the disk and then use the zipfile module or is there some way to do it without writing to the disk?

Note: I am not using the Django model with a FileField and the corresponding Form for various unrelated reasons.

What about checking the file extension? – danidee Mar 30 '17 at 14:20 — danidee, Mar 30 '17 at 14:20
Cannot be relied upon unfortunately for my application... – Luca Mar 30 '17 at 14:26 — Luca, Mar 30 '17 at 14:26

score 7 · Accepted Answer · edited May 23 '17 at 12:10

7

Yes, you should use zipfile module.

zipfile.is_zipfile(filename)

Returns True if filename is a valid ZIP file based on its magic number, otherwise returns False. filename may be a file or file-like object too. (Changed in version 3.1: Support for file and file-like objects.)

Another option:(not likely but your choice)

How to detect type of compression used on the file? (if no file extension is specified)

You can find the header formats in the descriptions:

Zip (.zip) format description, starts with 0x50, 0x4b, 0x03, 0x04 (unless empty — then the last two are 0x05, 0x06 or 0x06, 0x06)

edited May 23 '17 at 12:10

Community

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answered Mar 30 '17 at 14:33

nivhanin

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yeah, the thing is that the file will have to be stored to be able to use with `zipfile`. I guess there is no other really good way to do this. – Luca Mar 30 '17 at 14:42

score 0 · Answer 2 · answered Mar 30 '17 at 19:13

0

Save the filename of the pbject

Name = request.FILES['filename'].name

Then check if is a zip file

If Name.endswith('.zip'):
     print(True)

answered Mar 30 '17 at 19:13

Mattia

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It has the same issue as I mentioned before of having to store the file. I guess there is no really good and robust way to check an in-memory file. – Luca Mar 30 '17 at 21:42

django check if the uploaded file is a zip file

2 Answers2