Fix serializer bug

src/document/serializers.py

@@ -8,30 +8,42 @@ _max_count = 1
 class DocumentSerializer(serializers.ModelSerializer):
     uploaded_by = serializers.HiddenField(default=CurrentUserProfileDefault())
     uploaded_by_name = serializers.SerializerMethodField()
-    file = serializers.SerializerMethodField()
+    file_url = serializers.SerializerMethodField()
 
     class Meta:
         model = models.Document
-        fields = (
+        fields = [
             'uploaded_by',
             'uploaded_at',
             'name',
             'description',
+            'file_url',
             'file',
             'uploaded_by_name',
             'solution',
-        )
+        ]
+        
+        read_only_fields = [
+            'uploaded_by',
+            'uploaded_at',
+            'file_url',
+            'uploaded_by_name',
+        ]
+
+        extra_kwargs = {
+            'file': {'write_only': True},
+        }
 
     def to_representation(self, instance):
         data = super().to_representation(instance)
-        if not data['file']:
-            data['file'] = ""
+        if not data['file_url']:
+            data['file_url'] = ""
         return data
 
     def get_uploaded_by_name(self, obj):
         return obj.uploaded_by.full_name
 
-    def get_file(self, obj):
+    def get_file_url(self, obj):
         return f"/api/v1/documents/{obj.id}/download/"
 
     def validate_solution(self, value):
@@ -42,5 +54,5 @@ class DocumentSerializer(serializers.ModelSerializer):
             uploaded_by=profile, solution=value).count()
         if count >= _max_count:
             raise serializers.ValidationError(
-                f'You cant upload more than {max_count} document to one solution!')
+                f'You cant upload more than {_max_count} document to one solution!')
         return value