Trait QueryFunctionResolver 

pub trait QueryFunctionResolver: Send + Sync {
    // Required method
    fn resolve<'a>(
        &'a self,
        request: QueryFunctionRequest<'a>,
    ) -> Pin<Box<dyn Future<Output = Result<Value>> + Send + 'a>>;
}

Answers a function-backed root query field.

Registered on RuntimeConfig via with_query_function_resolver, parallel to with_before_mutation_gate.

The return value is the field’s data, not a response

For a single-item field: the entity document, or null. For a list field: an array of them. The engine projects the selection set over it, so the guest returns whatever the type declares and never a GraphQL envelope — which also means a guest cannot invent a field the schema does not declare, or return one the caller’s scopes deny.

Required Methods

fn resolve<'a>( &'a self, request: QueryFunctionRequest<'a>, ) -> Pin<Box<dyn Future<Output = Result<Value>> + Send + 'a>>

Invoke the function that backs this field.

Errors

Any error refuses the field. A resolver is expected to map its own failures — a missing module, a guest exception, a timeout — to an error that names the field, because by the time the engine sees it the only other thing it could say is “the query failed”.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors