BlogPostSerializer.py

class BlogPostSerializer(serializers.ModelSerializer):

	username 		= serializers.SerializerMethodField('get_username_from_author')
	image 			= serializers.SerializerMethodField('validate_image_url')

	class Meta:
		model = BlogPost
		fields = ['pk', 'title', 'slug', 'body', 'image', 'date_updated', 'username']


	def get_username_from_author(self, blog_post):
		username = blog_post.author.username
		return username

	def validate_image_url(self, blog_post):
		image = blog_post.image
		new_url = image.url
		if "?" in new_url:
			new_url = image.url[:image.url.rfind("?")]
		return new_url