我们如何从 apollo-server 模块传递 ApolloServer 中的数据源和合并的 graphql 模式和解析器？

Posted 2023-03-08

【中文标题】我们如何从 apollo-server 模块传递 ApolloServer 中的数据源和合并的 graphql 模式和解析器？

【英文标题】：How can we pass datasource and merged graphql schema and resolvers in ApolloServer from apollo-server module?

【发布时间】：2019-05-29 06:31:16

【问题描述】：

我有一种情况，我的架构和解析器位于各种不同的文件中。我已将架构和解析器导入到负责创建 apollo 服务器的 server.js 文件中。目前，我正在导入一组解析器和查询，而 server.js 文件中已经存在另一组查询和解析器。

这是 server.js 文件的内容。

    import "graphql-import-node";
import  ApolloServer, gql  from "apollo-server";
import  makeExecutableSchema  from "graphql-tools";
import merge from "lodash/merge";
import GithubFetchHelper from "./github/GithubFetchHelper";
import 
  resolvers as GithubResolvers,
  typeDefs as GithubTypeDef
 from "./github";

/**
 * Error Handler. Provides full stack - remove for production
 */

const books = [
  
    title: "Harry Potter and the Chamber of Secrets",
    author: "J.K. Rowling"
  ,
  
    title: "Jurassic Park",
    author: "Michael Crichton"
  
];

const typeDefs = gql`
  # Comments in GraphQL are defined with the hash (#) symbol.

  # This "Book" type can be used in other type declarations.
  type Book 
    title: String
    author: String
  

  # The "Query" type is the root of all GraphQL queries.
  # (A "Mutation" type will be covered later on.)
  type Query 
    books: [Book]
  
`;

const resolvers = 
  Query: 
    books: () => books
  
;

// typeDefs: [
//   project.typeDefs,
//   task.typeDefs,
//   search.typeDefs
// ].join(' '),
// resolvers: merge(, project.resolvers, task.resolvers, search.resolvers),
// context: 
//   models: 
//     project: project.model,
//     task: task.model
//   ,
//   loaders: loaders()
// 

const server = new ApolloServer(
  typeDefs: [typeDefs, GithubTypeDef],
  resolvers: merge(, resolvers, GithubResolvers),
  dataSources: () => 
    return 
      gitHubApi: new GithubFetchHelper()
    ;
  
);

server.listen().then(( url ) => 
  console.log(`????  Server ready at $url`);
);

export default server;

现在当我运行服务器时，我收到以下错误。任何帮助表示赞赏。

Error: Type "Query" was defined more than once.

我的尝试我参考了 apollo 文档以获取数据源以及使用来自 graphql-tools 的 gql 合并多个模式和解析器。但是我没有得到任何 gql 的实现，他们也使用了数据源。

感谢任何帮助。

注意：我对 Graphql 很陌生

【问题讨论】：

您在哪里能够弄清楚如何实现这一目标..？

【参考方案1】：

从代码中，您将 2 个 typedef 作为数组传递，这可能是您收到错误的原因。您需要将架构缝合在一起。见：

https://www.graphql-tools.com/docs/schema-stitching/stitch-combining-schemas https://blog.apollographql.com/the-next-generation-of-schema-stitching-2716b3b259c0

【参考方案2】：

假设您在主 js 文件中导入了架构和解析器，您可以按以下方式拼接它。 您可以使用 require-graphql-file 模块来简化 graphQL 架构导入。

import merge  from 'lodash'
import requireGraphQLFile from 'require-graphql-file';
import makeExecutableSchema  from 'apollo-server';

import resolver1 from  './resolvers/resolver1';
import resolver2 from  './resolvers/resolver2';
import resolver3 from  './resolvers/resolver3';

const schema1= requireGraphQLFile('./schema/schema1');
const schema2= requireGraphQLFile('./schema/schema2');
const schema3= requireGraphQLFile('./schema/schema3');

const resolvers = merge(resolver1, resolver2, resolver3)
const typeDef = gql `
type Query 
getData(filters:Filter,limit:Int,offset:Int):Result
`;

const schema = makeExecutableSchema(
typeDefs: [typeDef, schema1,schema2, schema3],
resolvers
);

const server = new ApolloServer(
    schema
);