strict parsing?

[christopinka]

How to have error if extra field found in JSON?

Is there a way to use validate="true" to fail if struct field name not found in JSON?

Thanks

[avivpxi]

@christopinka I'm not against having it as an option, we might get to prioritizing it. In the meantime feel free to submit a PR.

However, you can easily test it today by checking the existence of a key in the result map:

m, err := marshmallow.Unmarshal(...)

_, exists := m["field"]
if !exists {
  // error
}

I do agree that if you want it on all struct fields and not a specific one, this methods is inefficient.
Out of curiosity: which one is it? And do you actually need the capability of getting the extra fields to a map? Or just interested in knowing if there are missing fields?

[christopinka]

This is just speculative at this point. No pressing need, but interested in this effort.

It seems the main point currently of using marshmallow is to extract as much data as possible and be performant in the process and also use the map for errors or reporting as shown above?

I would need some direction to know what options there are. Would using struct tags fit this project?

It seems like knowing if there are extra fields in the json that don't match your struct schema would have value in some cases. It appears there 'modes' that support this?

Looking at examples and documentation more...

It seems like there must be a reason struct tags were avoided, as used in this project? https://github.com/go-playground/validator

Thanks!

[avivpxi]

@christopinka I don't see a reason to overcomplicate. Marshmallow is not intended as a validation library and the aim is to stay as simple as possible and as compatible as possible to the native json package, and to focus on the specific domain of retaining data while unmarshalling. Unless we have a very solid justification, I'd stay away from adding struct tags.

However, validating no missing fields is something closer to the domain of marshmallow and is more reasonable to provide. If you have a concrete use case that you're facing, let's talk requirements and then we should be able to provide that for you.