forms.py 文件源码

def clean(self, value, *args, **kwargs):
        value = super().clean(value, *args, **kwargs)
        if isinstance(value, UploadedFile):
            try:
                from PIL import Image
            except ImportError:
                return value

            value.open('rb')
            value.seek(0)
            try:
                with Image.open(value) as im, tempfile.NamedTemporaryFile('rb', suffix='.png') as tmpfile:
                    im.save(tmpfile.name)
                    tmpfile.seek(0)
                    return SimpleUploadedFile('picture.png', tmpfile.read(), 'image png')
            except IOError:
                logger.exception('Could not convert image to PNG.')
                raise ValidationError(
                    _('The file you uploaded could not be converted to PNG format.')
                )

        return value