如何自定义GraphQL查询验证错误消息

Question

我在数据库上实现查询层，使用GraphQl和Spring Boot项目在sql数据库上执行CRUD操作。在GraphQL模式中，我提到了一些必须的字段，当这些字段在查询中没有提到时，它会以默认格式返回200状态代码的ValidationError错误消息。

错误：

{
"data": null,
"errors": [
    {
         value=StringValue{value='1235'}}]}}]}' is missing required fields '[book_type]' @ 'create_book'",
        "locations": [
            {
                "line": 3,
                "column": 23,
                "sourceName": null
            }
        ],
        "description": "argument 'insert' with value value=StringValue{value='1235'}}]}}]}' is missing required fields '[book_type]'",
        "validationErrorType": "WrongType",
        "queryPath": [
            "create_book"
        ],
        "errorType": "ValidationError",
        "path": null,
        "extensions": null
    }
],
"dataPresent": false,
"extensions": null
}

这是我的代码与层架构模式

控制器：

@Autowired
private GraphQLServer graphQlServer;

@PostMapping("test")
public ResponseEntity<Object> graphQl(@RequestBody String body){
    ExecutionResult response = graphQlServer.execute(body);

    return ResponseEntity.ok(response);
}

服务：

@Service
public class GraphQLServer {

@Autowired
private GraphQL graphQl;

public ExecutionResult execute(String query) {
    return graphQl.execute(query);
   }

}

配置：

@Bean
public GraphQL loadSchema() throws IOException {

    File schemaFile = schemaResource.getFile();

    TypeDefinitionRegistry typeRegistry = new SchemaParser().parse(schemaFile);
    RuntimeWiring wiring = buildRuntimeWiring();
    GraphQLSchema schema = new SchemaGenerator().makeExecutableSchema(typeRegistry, wiring);
    return GraphQL.newGraphQL(schema).build();
}

private RuntimeWiring buildRuntimeWiring() {

    return RuntimeWiring.newRuntimeWiring()
            .type("Mutation", mutationWiring -> mutationWiring.dataFetcher("create_book", bookDataFetcher))
            .build();

}

BookDataFetcher：

@Override
public Map<String, Object> get(DataFetchingEnvironment environment) {

    //return data from db by getting Map properties from environment

}

上面的代码按预期工作，但我这里的问题是如何自定义错误消息？在错误消息中，我想提及状态400，因为这是来自客户端的错误请求

Answer 1

首先，您应该在ExecutionResult上调用toSpecification（），以确保响应符合GraphQL规范。

默认情况下，graphql java只提供一个ExecutionResult的实现，即ExecutionResultImpl，因此您可以将ExecutionResult强制转换为它，以便使用它的transform（）更新其状态。

ExecutionResultImpl内部包含graphql java检测到的所有错误。它们都在GraphQLError的子类中，这意味着您必须在定制期间将其强制转换为特定的子类。

在您的例子中，子类是ValidationError，代码如下所示：

@PostMapping("test")
public ResponseEntity<Object> graphQl(@RequestBody String body){

    ExecutionResult response = graphQlServer.execute(body);

    ExecutionResultImpl responseImpl = (ExecutionResultImpl) response;

    List<GraphQLError> customizedErrors = Lists.newArrayList();
    for (GraphQLError gqlError : responseImpl.getErrors()) {
            //Do your error custmosation here....
            GraphQLError customizedError = gqlError;
            if (gqlError instanceof ValidationError) {
                ValidationError error = (ValidationError) gqlError;
                customizedError = new ValidationError(error.getValidationErrorType(), error.getLocations(),
                        "Customizing some error message blablabla....");
            }
            customizedErrors.add(customizedError);
    }

    Map<String, Object> specResponse = responseImpl.transform(b->b.errors(customizedErrors)).toSpecification();

    return ResponseEntity.ok(specResponse);
}