Difference between fields and read_only_fields in ModelSerializer

Using Django
1

I am writing a serializer for my model which inherits serializers.ModelSerializer.
I only have one field to serialize.
I am curious to know if I have to put that field in both fields and read_only_fields.
I am using that serializer in APIView only for get method.
What actually happends behind if I put a field in read_only_fields?
I read the django-restframework documentation but did not understand the point.

Thanks in advance.

2

My take on it is that they serve two different purposes.

Listing the fields in the fields attribute identify which fields to include on a retrieval.

Listing the fields in read_only_fields would prevent fields from being changed in an update. The section on Specifying read only fields implies to me that it’s the same as specifying editable=False on each field or having the field defined as an AutoField.

If you’re only providing a read-only access, then I don’t see where the read_only_fields attribute will do anything at all.

3

Understood.
So I think I don’t need to add the field to read_only_fields if I only provide GET method for API.
What do you think?

4

That’s my understanding, yes.

5

Okay
That makes sense

Thank you again. :slight_smile:

6

Hi, Ken!

I think I still need to add my field to read_only_fields.
If I don’t do that, that field is filterable.
For my case, I should not allow that.

Regards. :wink:

7

You’ve got me curious here - what do you mean by filterable for this? (Are you generating a response using an APIView class? Implementing only a get method? Using any mixins with your class?)

8

I am using swagger in my Django project and use that to test APIs.
Excluding the field from read_only_fields resulted that field available for parameter of GET request.
Anyway it;s not an issue.

I created another topic which might interest you