Validate a file before Uploading using python magic

Question

I am using python magic to validate a file before uploading so for that I am following the below link:

https://djangosnippets.org/snippets/3039/

validators.py file:

from django.core.exceptions import ValidationError
import magic


class MimetypeValidator(object):
    def __init__(self, mimetypes):
        self.mimetypes = mimetypes

    def __call__(self, value):
        try:
            mime_byt = magic.from_buffer(value.read(1024), mime=True)
            mime = mime_byt.decode(encoding='UTF-8')
            if mime not in self.mimetypes:
                raise ValidationError('%s is not an acceptable file type' % value)
        except AttributeError as e:
            raise ValidationError('This value could not be validated for file type' % value)

here is my form.py file:

class FileForm(forms.ModelForm):
    file = forms.FileField(
        label='Select a File *',
        allow_empty_file=False,
        validators=[MimetypeValidator('application/pdf')],
        help_text='Max. Size - 25 MB')

    class Meta:
        model = File
        fields = ('file')

SO I am able to upload a pdf file with this python magic logic but I also want to allow to upload a image tiff file and restrict the file size to 25 MB.

How can I implement this by using python magic?

Ben · Accepted Answer · 2016-05-26 07:59:56Z

2

You don't need any library to do this - you can check the uploaded size of a file in the clean method on the form:

def clean_file(self):
    file = self.cleaned_data['file']
    if file.size > 25000000:
        raise ValidationError('The file is too big')
    return file

edited May 26, 2016 at 7:59

answered May 26, 2016 at 7:38

Ben

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8 Comments

Sneha Shinde Over a year ago

Thanks. I also want to allow a image tiff file so do you have any idea how to add it?

Ben Over a year ago

Exactly the same way as you're checking for a PDF... You know how to do that bit already.

Sneha Shinde Over a year ago

I mean I want to only allow both the pdf and tiff file while uploading the file.

Ben Over a year ago

Do you mean want to allow either an unlimited size PDF, or a 25MB tiff? Or do you want to allow either a PDF or tiff, both restricted to 25MB?

Sneha Shinde Over a year ago

Yes I want to allow either a PDF or tiff, both restricted to 25MB.

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