Rename Argument using Directive

[skumaravelan]

Hi all, I am looking for rename directive using graphql Java. Is there a directive available that I can use?

[knotenpunkt]

do you mean something like that?

Customising PropertyDataFetcher
As mentioned above graphql.schema.PropertyDataFetcher is the default data fetcher for fields in graphql-java and it will use standard patterns for fetching object field values.

It supports a POJO approach and a Map approach in a Java idiomatic way. By default it assumes that for a graphql field fieldX it can find a POJO property called fieldX or a map key called fieldX if the backing object is a Map.

However you may have small differences between your graphql schema naming and runtime object naming. For example imagine that Product.description is actually represented as getDesc() in the runtime backing Java object.

If you are using SDL to specify your schema then you can use the @fetch directive to indicate this remapping.

 directive @fetch(from : String!) on FIELD_DEFINITION type Product { id : ID name : String description : String @fetch(from:"desc") cost : Float tax : Float } 

the logic behind @fetch is still implemented in graphql-java, but you must "activate" it/make-it-accessable by writing the directive statement explicit into your graphql-schema like in that code-example here, see line 1

take a look here: https://www.graphql-java.com/documentation/v16/data-fetching/

[knotenpunkt]

and in the origin-datafetchers you fetch the data then not from dfe.getArguments but from dfe.getContext().get("myNewArguments") or something like that.

if you want also the propertyFetcher work with that, you must write for that proxy-classes

But as i sayed maybe there is still a better and easier solution @bbakerman can give

[knotenpunkt]

@skumaravelan im not sure if you saw this replies here, because they are hidden on default, you must click a "button" to see that, maybe that helps

[skumaravelan]

@knotenpunkt : I am trying the follow the code example that is referenced in here. I am not quite following on the datafetcher-interceptor. Do I need to use both SchemarDirectiveWiring, SchemaTransformation? Please give me the steps in the form of code would help. I am not getting where we are setting up dfe.getContext().get("myNewArguments") in order for me to retrieve the modified argument.

[skumaravelan]

@knotenpunkt : Could you please help me realizing the solution? i am having challenge in copy the argument to a tmp map and change there the keys to the names, you get from your directive. And where could I create a context in this algorithm ? I believe the idea is cool and will work for me, but I am not able to follow the process like datafetcher-interceptor you must create in the SchemaTransformation and so on.

[knotenpunkt]

@skumaravelan see my answer in a new thread

[skumaravelan]

Rename works onField of SchemaDirectiveWiring and has Datafetcher. But I need an example, how i could use the datafetcher for onArgument method. So that the client doesn't' need to know about the field name that app can use internally, Please share an example or show me how to get that working like onField method. When I call, dataFetchingEnvironment.getArguments(), need the field with replaced field name and the values.

public GraphQLFieldDefinition onField(SchemaDirectiveWiringEnvironment<GraphQLFieldDefinition> environment) { GraphQLFieldDefinition field = (GraphQLFieldDefinition)environment.getElement(); String fetchName = this.atRenameSupport(field.getName(), field.getDirectives()); DataFetcher dataFetcher = new PropertyDataFetcher(fetchName); return field.transform((builder) -> { builder.dataFetcher(dataFetcher); }); } @Override public GraphQLArgument onArgument(SchemaDirectiveWiringEnvironment<GraphQLArgument> environment) { GraphQLArgument graphQLArgument = environment.getElement(); String fetchName = this.atRenameSupport(graphQLArgument.getName(), graphQLArgument.getDirectives()); DataFetcher dataFetcher = new PropertyDataFetcher(fetchName); return graphQLArgument.transform((builder -> { builder.name(fetchName); })); } 

[knotenpunkt]

ehm i tried it with onArgument, but that method is nerver called but i added a few argumentsDirectives into my schema,

maybe thats an bug? @bbakerman maybe you can take a look on it if the onArgument-method is called.

i did the following:

extend type Query{ xxxxx(yyyyy: [String!] @fetch2(from: "hicks"), ......

@Override public GraphQLArgument onArgument(SchemaDirectiveWiringEnvironment<GraphQLArgument> environment) { System.out.println("debug-pointx"); .....

but its never called

[skumaravelan]

I am able to add a directive in the fields level and onArgument is getting called, but when I rename the field it is getting changed in the published schema, rather I want to change only internally so that I can see updated values using the DataFetcher dataFetcher. Please help me to resolve, How I can update and read for the internal use.

[knotenpunkt]

@skumaravelan take a look on the other answer-thread here in this topic, my replies could be hidden, you must unfold then you can see.... there i described you briefly how you could use internaly other namings

[skumaravelan]

I am looking for an example that was described to to use graphql.schema.transform.FieldVisibilitySchemaTransformation And also context based example. Please share an example that I can try to check out that feature.

[knotenpunkt]

public class GraphQLTypeVisitorStubWithCodeRegistry extends GraphQLTypeVisitorStub { @Getter protected GraphQLCodeRegistry.Builder graphQLCodeRegistryBuilder; @Getter protected GraphQLSchema graphQLSchema; public void registerCodeRegistryBuilder(GraphQLCodeRegistry.Builder graphQLCodeRegistryBuilder) { this.graphQLCodeRegistryBuilder = graphQLCodeRegistryBuilder; } public void registerGraphQLSchema(GraphQLSchema graphQLSchema) { this.graphQLSchema = graphQLSchema; } }

public class ArgumentsDirectiveVisitor extends GraphQLTypeVisitorStubWithCodeRegistry { @Override public TraversalControl visitGraphQLFieldDefinition(GraphQLFieldDefinition fieldDefinition, TraverserContext<GraphQLSchemaElement> context) { GraphQLFieldsContainer parentContainerType = (GraphQLFieldsContainer) context.getParentContext().thisNode(); newDataFetcher = (dfe) ->{ final Map<String, Object> originArguments = dfe.getArguments(); final GraphQLContext dfeContext = (GraphQLContext) dfe.getContext(); final LinkedHashMap<String, Object> mySpecialArguments = dfeContext.getOrDefault("mySpecialArguments", new LinkedHashMap<>()); mySpecialArguments.put("...","..."); //do something with the originArguments related to the directives return this.graphQLCodeRegistryBuilder.getDataFetcher(parentContainerType, fieldDefinition).get(dfe); }; this.graphQLCodeRegistryBuilder.dataFetcher(coordinates(parentContainerType, fieldDefintion), newDataFetcher); }

So its some code i use changed a little bit to give you an idea, so briefly im not sure which exactly method you must override of GraphQLTypeVisitorStub, but it should show you how you can put into it a datafetcher interceptor, the important code is the newDataetcher-lambda and how you can register it in the registry, for that you must inject the registry.....

because i use different visitors in my code i putted it into a abstract parent class. The registry you get nearly on that location where you boostrap up your graphql engine, i think you will find it...... ok moment i give you some code:

 SchemaTransformer schemaTransformer = new SchemaTransformer(); GraphQLCodeRegistry.Builder codeRegistryBuilder = newCodeRegistry(graphQLSchema.getCodeRegistry()); for (GraphQLTypeVisitorStubWithCodeRegistry value : this.graphQLTypeVisitor) { value.registerCodeRegistryBuilder(codeRegistryBuilder); value.registerGraphQLSchema(graphQLSchema); graphQLSchema = schemaTransformer.transform(graphQLSchema, value); } graphQLSchema = graphQLSchema.transform(builder -> { builder.codeRegistry(codeRegistryBuilder.build()); }); this.graphQL = GraphQL.newGraphQL(graphQLSchema).build(); return this;

the graphQLSchema itself i need for something other in my code, that you dont need

[knotenpunkt]

you should not manipulated the origin dfe but simulate a manipulation with the help of, i think proxy-pattern is the correct word for it, with a proxy and manipulate class on runtime.

MyDfeManipulator is a class extends DataFetchingEnvironment { this.origin; publicMyDfeManipulator (DataFetchingEnvironment origin) { this.origin=origin } @Override public ???? getArguments(); { take this.origin.getArguments() change in a tmp-copy the argument-keys return the tmp-copy } }

[skumaravelan]

@knotenpunkt DataFetchingEnvironment is an interface, idea is to override the getArgument, where will be attaching the new DFE, in the transformer or schema directiveWiring ?

[knotenpunkt]

ah ok if it is an interface than write a special method for getArgument and delegate the other methods to the origin unprocessed.

if directiveWiring works, then you can do it there, the transformer should work in any case (i hope^^)

[skumaravelan]

@knotenpunkt Could you please point me, where is the current implementation of getArguments method implementation, I am still searching where in the code the arguments map is getting populated?

[skumaravelan]

@knotenpunkt, changing and fetching in through the transformer is quite cumbersome, I am trying to get both list of arguments having a rename directive together in a map form, so that I can apply the key rename using the resultant map.
How could we combine these two steps into one? is there any alternative one can suggest ?

 // all the arguments with our @rename directive List<String> argsWithLengthDirective = dataFetchingEnvironment.getFieldDefinition() .getArguments() .stream() .filter(arg -> arg.getDirective(RENAME) != null) .map(GraphQLArgument::getName) .collect(Collectors.toList()); for (String argName : argsWithLengthDirective) { GraphQLArgument argument = dataFetchingEnvironment.getFieldDefinition().getArgument(argName); GraphQLDirective renameDirective = argument.getDirective("rename"); newMap.put(argument.getName(), String.valueOf(renameDirective.getArgument("attribute").getValue())); }