upload validator field django

#coding: utf-8

from django.db.models import FileField
from django.forms import forms
from django.template.defaultfilters import filesizeformat
from django.utils.translation import ugettext_lazy as _



class ContentTypeRestrictedFileField(FileField):
	"""
		Same as FileField, but you can specify:
		* content_types - list containing allowed content_types. Example: ['application/pdf', 'image/jpeg']
		* max_upload_size - a number indicating the maximum file size allowed for upload.
			2.5MB - 2621440
			5MB - 5242880
			10MB - 10485760
			20MB - 20971520
			50MB - 5242880
			100MB 104857600
			250MB - 214958080
			500MB - 429916160
	"""
	def __init__(self, content_types=None, max_upload_size=None, **kwargs):
		self.content_types = content_types
		self.max_upload_size = max_upload_size

		super(ContentTypeRestrictedFileField, self).__init__(**kwargs)

	def clean(self, *args, **kwargs):
		data = super(ContentTypeRestrictedFileField, self).clean(*args, **kwargs)

		file = data.file
		try:
			content_type = file.content_type
			if content_type in self.content_types:
				if file._size > self.max_upload_size:
					raise forms.ValidationError(_('Please keep filesize under %s. Current filesize %s') % (filesizeformat(self.max_upload_size), filesizeformat(file._size)))
			else:
				raise forms.ValidationError(_('Filetype not supported.'))
		except AttributeError:
			pass

		return data