Hey, I'm trying to inspect the request when creating a `GraphQLContext` to be able to customize a ca...

# graphql-kotlin

[herder]

Hey, I'm trying to inspect the request when creating a GraphQLContext to be able to customize a callout to an external service, but I can't find how to get hold of the actual query body from the request? Is there a way to get hold of the raw query when creating my context?

[Dariusz Kuc]

assuming you are using graphql-kotlin-spring-server , creation of context happens before parsing of the query

[Dariusz Kuc]

since it executes in a webfilter technically you can read your request payload but I am unsure if thats a good idea

[Dariusz Kuc]

*i’d say you probably should not do it as it is a pretty heavy operation

[Dariusz Kuc]

when resolving the fields you do have access to environment (and context) which you could inspect to trigger different behavior

[herder]

thanks! what i really need is to know exactly which fields were included in the query - is there an easy way to get hold of that? or do you mean that this is accessible in the environment?

[herder]

There is a request.formData that is supposed to be cached, but I don't find any payload there

[Dariusz Kuc]

yeah environment will have the info

[Dariusz Kuc]

accessing this information when building out context will be troublesome -> i.e. you will need to read post body (heavy operation that will have to be repeated afterwards anyway) and then parse it (again throwaway work)

[Dariusz Kuc]

you could look into doing some custom query handler that performs context construction (instead of webfilter) but you would still end up parsing query twice

[herder]

Ah, so maybe it's better to get the environment injected in the Query method then?

[Dariusz Kuc]

*unless you rewrite graphql java logic to use your parsed result

[Dariusz Kuc]

yep

[Dariusz Kuc]

i’d go with environment

[herder]

that would work great as well - doesn't have to be the context as far as I'm concerned, even if it would look a bit cleaner 🙂 Thanks a lot for the help!

[Dariusz Kuc]

👍 good luck

[Shane Myrick]

The other option is using graphql-java instrumentation https://www.graphql-java.com/documentation/v15/instrumentation/

But I think accessing the DataFetchingEnvironment in the query is probably best: https://expediagroup.github.io/graphql-kotlin/docs/schema-generator/execution/data-fetching-environment

[herder]

Thanks! the thing is that I need to know the query before I construct the return type, so unless I'm misunderstanding I can't use a`DataFetchingEnvironmet` to get the query, since that's only applied on getters on fields?
I was thinking if it was possible to customize the queryHandler logic so that it inspects the Reactor subscription context and checks if there is a GraphQlContext there, and if the GraphQlContext implements some marker interface like GraphQlRequestAware it injects the constructed query there via some setter.
Would that make any sense? I'm a bit new to the project, so would appreciate any feedback 🙂

[Dariusz Kuc]

DataFetchingEnvironment is available when resolving any field but graphql-kotlin can automatically inject it as a function parameter, e.g. your top level query where you can read it and then apply some custom logic based on it (i.e. call X or Y)

can you elaborate more on your use case? it sounds like you are trying to do something that you probably should not be doing (or there is a simpler way of doing it)

[herder]

Sorry, my notifications seem to be wonky, so I didn't see this...
My use case is that we're talking to a gRPC service - the GraphQL service would essentially be a proxy to it - and are using field masks when making the request, which means that I do a request for a full object and not making callouts for certain fields.
I thought I'd send a PR to describe what would work for me - should be ready quite soon.

[herder]

Ah, the DataFetcherEnvironment does work now - I must have done something wrong while trying to get it injected before. Thanks again!