Grails - a better way to exclude class name from default json converters in groovy?

Question

I have been writing custom marshallers in a grails project for the purposes of being able to exclude some fields from the json model such as the class names. I am registering the marshallers through a spring bean which is called in the bootstrap.

I find though that most of this marshalling code is quite repetitive and the techniques leads to too many marshallers.

I'd like to know if there is a more generic was to always ignore certain fields from JSON conversion so I don't have to always write a custom marshaller for everything.

How could I override the default groovy JSON converters?

Steve Goodman · Answer 1 · 2012-10-22T16:27:51.910

If you use the InstanceMethodBasedMarshaller, you'll simply be able to define a toJSON method on each of your domain classes. This overcomes the problem of having to register many custom marshallers; instead you'll have one marshaller to rule them all.

However, it simply shifts the burden of creating a custom marshaller to writing a custom toJSON() implementation in each of your domain classes. To resolve this, you might take advantage of groovy categories, which are designed to provide common behavior across unrelated classes ala the strategy pattern. Something like:

//Category
class JSONOutputCategory {
    static customizeJSON(Object self) {
        // do whatever standard thing here
    }
}

//Domain
class MyDomain {
...
    public void toJSON(JSON json) {
        use(JSONOutputCategory){
            json.build {
               customizeJSON(this)
            }
        }
    }
}

CAVEAT EMPTOR: I haven't tested this at all, it's more a concept than an impl.

Grails - a better way to exclude class name from default json converters in groovy?

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