Custom file field with relative url

base/serializers.py

@@ -0,0 +1,12 @@
+from rest_framework import fields
+
+
+class RelativeUrlFileField(fields.FileField):
+    def to_representation(self, value):
+        request = self.context.pop('request', None)
+
+        representation = super().to_representation(value)
+
+        self.context['request'] = request
+
+        return representation

competition/serializers.py

@@ -1,8 +1,10 @@
 from django.contrib.auth.models import AnonymousUser
+from django.db.models import FileField
 from django_typomatic import ts_interface
 from rest_framework import serializers
 from rest_framework.exceptions import ValidationError
 
+from base.serializers import RelativeUrlFileField
 from competition import models
 from personal.serializers import ProfileShortSerializer, SchoolShortSerializer
 
@@ -42,6 +44,11 @@ class Meta:
         model = models.Publication
         fields = '__all__'
 
+    def __init__(self, instance=None, data=..., **kwargs):
+        super().__init__(instance, data, **kwargs)
+
+        self.serializer_field_mapping[FileField] = RelativeUrlFileField
+
     def get_verbose_name(self, obj):
         return str(obj)