How to access the requested fields inside of a Controller, or the final map result before sending a response?

[fhernandez-clgx]

As the title said, I am wondering if there is a way to either access the requested fields, for example, in the following query:

query { geoMappings(stateId: "01") { stateId stateAbbr stateName } }

I would like to know that the user requested the stateId, stateAbbr and stateName fields.

Also, is it possible to access and manipulate the resulting map before sending a response to the client? In the previous query, I require to remove any duplicate objects in the resulting map, regardless of there existing multiple objects that match the condition in the database.

[bclozel]

You can declare a DataFetchingFieldSelectionSet argument on your controller, this should give you the information you are looking for.

As for your second question I'm not sure. In your example the geoMappings query would map to a @QueryMapping annotated method that returns a collection of GeoMapping objects that you're fetching from a data source. You could perform this deduplication at the controller level maybe?

[fhernandez-clgx]

As for your second question I'm not sure. In your example the geoMappings query would map to a @QueryMapping annotated method that returns a collection of GeoMapping objects that you're fetching from a data source. You could perform this deduplication at the controller level maybe?

The second question relates to the GraphQL Engine processing that happens after the controller returns. In the controller I cannot delete duplicates because they are different database objects, but they become duplicates after the unneeded fields are removed, and that's where I want them to be removed.

[bclozel]

I'm not aware of any particular hook point to perform that operation.
I'd say that if objects are different at the data fetcher level, they probably have a different technical ID so if the client does not ask this ID and sees those as duplicates, it's not really a problem because the data sent is right.