Adding checksums to file attributes

fixes #4827
https://pulp.plan.io/issues/4827

pulp_file/app/serializers.py

@@ -3,6 +3,7 @@
 from rest_framework import serializers
 
 from pulpcore.plugin.serializers import (
+    ContentChecksumSerializer,
     DetailRelatedField,
     PublicationDistributionSerializer,
     PublicationSerializer,
@@ -14,7 +15,7 @@
 from .models import FileContent, FileDistribution, FileRemote, FilePublication
 
 
-class FileContentSerializer(SingleArtifactContentSerializer):
+class FileContentSerializer(SingleArtifactContentSerializer, ContentChecksumSerializer):
     """
     Serializer for File Content.
     """
@@ -24,6 +25,8 @@ class FileContentSerializer(SingleArtifactContentSerializer):
         validators=[relative_path_validator],
     )
 
+    checksum = serializers
+
     def validate(self, data):
         """Validate the FileContent data."""
         data = super().validate(data)
@@ -45,7 +48,7 @@ def validate(self, data):
     class Meta:
         fields = tuple(
             set(SingleArtifactContentSerializer.Meta.fields) - {'_relative_path'}
-        ) + ('relative_path',)
+        ) + ContentChecksumSerializer.Meta.fields + ('relative_path',)
         model = FileContent