Injecting Spring beans into data fetchers

[mushketyk]

I am puzzled about how should I inject spring beans into data fetchers.
One way could be to pass ApplicationContext into graphQL.execute like this:

@Autowired
ApplicationContext applicationContext
...
graphQL.execute("{query}", applicationContext).<Map<String, Object>> getData()

Then DataFetcher implementation would look like:

class MovieDataFetcher implements DataFetcher<List<Item>> {

    @Override
    List<Item> get(DataFetchingEnvironment environment) {
        ApplicationContext applicationContext = environment.<ApplicationContext> getContext()
        MoviesRepository moviesRepository = applicationContext.getBean(MoviesRepository)
        return moviesRepository.findAll()
    }
}

What is the preferred way to do this with graphql-spring-boot?

[apottere]

That seems like a good solution. Right now, the servlet used doesn't expose a way to alter the context:

    @Override
    protected GraphQLContext createContext(Optional<HttpServletRequest> request, Optional<HttpServletResponse> response) {
        return new GraphQLContext(request, response);
    }

That could be extended to allow you to pass your own context creator that adds the applicationContext.

Static datafetchers are annoying, which is why I created my own library (https://github.com/graphql-java/graphql-java-tools) that let you have state, which means you can @Autowire beans into them.

[mushketyk]

Hi @apottere
Thank you for the response.

I think it would be a good idea to allow altering the context to increase application flexibility.
Regarding graphql-java-tools. Does it work with graphql-annotations?

[apottere]

No, it's not compatible with annotations. They're both graphql-schema generation libraries, but they have different philosophies :)

[apottere]

Currently releasing this: graphql-java-kickstart/graphql-java-servlet@0b62669

Once that's done, I'll update this project to expose it.

[mushketyk]

Thank you for the update @apottere. I think this commit may help to close #5 as well!

[mushketyk]

A temporary workaround is to use graphql-java-servlet instead of graphql-spring-boot and define these beans:

    // Register GraphQL servlet
    @Bean
    ServletRegistrationBean servletRegistrationBean() {
        return new ServletRegistrationBean(graphQLServlet(), "/graphql/*");
    }

    @Bean
    GraphQLServlet graphQLServlet() {
        // Return custom GraphQL context
        new SimpleGraphQLServlet(graphQLSchema()) {
            @Override
            protected GraphQLContext createContext(Optional<HttpServletRequest> request, Optional<HttpServletResponse> response) {
                return new SpringGraphQLContext(request, response, applicationContext);
            }
        }
    }

and SpringGraphQLContext would look like this:

class SpringGraphQLContext extends GraphQLContext {

    private ApplicationContext applicationContext

    SpringGraphQLContext(Optional<HttpServletRequest> request,
                         Optional<HttpServletResponse> response,
                         ApplicationContext applicationContext) {
        super(request, response);
        this.applicationContext = applicationContext;
    }

    ApplicationContext getApplicationContext() {
        return applicationContext;
    }
}

than one can access ApplicationContext in a data fetcher:

List<Movie> get(DataFetchingEnvironment environment) {
    ApplicationContext applicationContext = environment.<SpringGraphQLContext> getContext().getApplicationContext()
}

[apottere]

graphql-spring-boot 3.6.0 is released, and allows you to specify a GraphQLContextBuilder bean.