Unable to get rid of 'Exception while fetching data(/{apiName})' in graphql-spqr-spring-boot-starter - exception

Question

I’m using ‘graphql-spqr-spring-boot-starter’ library version 0.0.4 of ‘io.leangen.graphql’. I'm able to customize errors. See the below code and screenshot for reference:
Models:
#Getter
#Setter
#ToString
#Entity
#Accessors
public class Student {
#Id
#GraphQLQuery(name = "id", description = "A Student's ID")
private Long id;
#GraphQLQuery(name = "name", description = "A student's name")
private String name;
private String addr;
}
Service class:
#Service
#GraphQLApi
public class StudentService{
private final StudentRepository studentRepository;
private final AddressRepository addressRepository;
public StudentService(StudentRepository studentRepository, AddressRepository addressRepository) {
this.addressRepository = addressRepository;
this.studentRepository = studentRepository;
}
#GraphQLQuery(name = "allStudents")
public List<Student> getAllStudents() {
return studentRepository.findAll();
}
#GraphQLQuery(name = "student")
public Optional<Student> getStudentById(#GraphQLArgument(name = "id") Long id) {
if(studentRepository.findById(id) != null)
return studentRepository.findById(id);
throw new StudentNotFoundException("We were unable to find a student with the provided id", "id");
}
#GraphQLMutation(name = "saveStudent")
public Student saveStudent(#GraphQLArgument(name = "student") Student student) {
if(student.getId() == null)
throw new NoIdException("Please provide an Id to create a Student entry.");
return studentRepository.save(student);
}
}
Customized Exception class:
import java.util.List;
import graphql.ErrorType;
import graphql.GraphQLError;
import graphql.language.SourceLocation;
public class NoIdException extends RuntimeException implements GraphQLError {
private String noIdMsg;
public NoIdException(String noIdMsg) {
this.noIdMsg = noIdMsg;
}
#Override
public List<SourceLocation> getLocations() {
// TODO Auto-generated method stub
return null;
}
#Override
public ErrorType getErrorType() {
// TODO Auto-generated method stub
return ErrorType.ValidationError;
}
#Override
public String getMessage() {
// TODO Auto-generated method stub
return noIdMsg;
}
}
However, I’m not sure how to get rid of Exception while fetching data (/saveStudent) as seen on the above screenshot for the message field. I know we can have GraphQLExceptionHandler class which implements GraphQLErrorHandler (graphql-java-kickstart). But what is the option for sqpr-spring-boot-starter?
import graphql.*;
import graphql.kickstart.execution.error.*;
import org.springframework.stereotype.*;
import java.util.*;
import java.util.stream.*;
#Component
public class GraphQLExceptionHandler implements GraphQLErrorHandler {
#Override
public List<GraphQLError> processErrors(List<GraphQLError> list) {
return list.stream().map(this::getNested).collect(Collectors.toList());
}
private GraphQLError getNested(GraphQLError error) {
if (error instanceof ExceptionWhileDataFetching) {
ExceptionWhileDataFetching exceptionError = (ExceptionWhileDataFetching) error;
if (exceptionError.getException() instanceof GraphQLError) {
return (GraphQLError) exceptionError.getException();
}
}
return error;
}
}
Could someone please help me how can I remove this statement and send just the specific message?

Answer 1

You can create a Bean and override DataFetcherExceptionHandler. To override it, you have to override the execution strategy too:
#Bean
public GraphQL graphQL(GraphQLSchema schema) {
return GraphQL.newGraphQL(schema)
.queryExecutionStrategy(new AsyncExecutionStrategy(new CustomDataFetcherExceptionHandler()))
.mutationExecutionStrategy(new AsyncSerialExecutionStrategy(new CustomDataFetcherExceptionHandler()))
.build();
}
private static class CustomDataFetcherExceptionHandler implements DataFetcherExceptionHandler {
#Override
public DataFetcherExceptionHandlerResult onException(DataFetcherExceptionHandlerParameters handlerParameters) {
Throwable exception = handlerParameters.getException();
SourceLocation sourceLocation = handlerParameters.getSourceLocation();
CustomExceptionWhileDataFetching error = new CustomExceptionWhileDataFetching(exception, sourceLocation);
return DataFetcherExceptionHandlerResult.newResult().error(error).build();
}
}
private static class CustomExceptionWhileDataFetching implements GraphQLError {
private final String message;
private final List<SourceLocation> locations;
public CustomExceptionWhileDataFetching(Throwable exception, SourceLocation sourceLocation) {
this.locations = Collections.singletonList(sourceLocation);
this.message = exception.getMessage();
}
#Override
public String getMessage() {
return this.message;
}
#Override
public List<SourceLocation> getLocations() {
return this.locations;
}
#Override
public ErrorClassification getErrorType() {
return ErrorType.DataFetchingException;
}
}