抽象类型节点必须在运行时解析为字段 Root.node 的对象类型，值为 \"\"，已收到 \"null\"。

Question

我正在使用 React 和 Relay 实现搜索功能。下面是我的 schema.js

var { nodeInterface, nodeField } = nodeDefinitions(
  (globalId) => {
    var { type, id } = fromGlobalId(globalId);
    if (type === 'User') {
      return getUser(id);
    }else if (type === 'Post') {
      return getPost(id);
    }else if (type === 'Setting') {
      return getSetting(id);
    }
    return null;
  },
  (obj) => {
    if (obj instanceof User) {
      return userType;
    }else if (obj instanceof Post) {
      return postType;
    }else if (obj instanceof Setting) {
      return settingType;
    }
    return null;
  }
);

var postType = new GraphQLObjectType({
  name: 'Post',
  fields: {
    _id: {
      type: new GraphQLNonNull(GraphQLID)
    },
    createdAt: {
      type: GraphQLString
    },
    id: globalIdField('Post'),
    title: {
      type: GraphQLString
    },
    color: {
      type: GraphQLString
    },
    userId: globalIdField('User'),
    username: {
      type: GraphQLString,
      resolve: (post) => getUserById(post.userId),
    },
    content: {
      type: GraphQLString
    },
    images: {
      type: postImageType,
      description: "Post's main image links"
    }
  },
  interfaces: [nodeInterface]
});
const {
  connectionType: postConnection,
} = connectionDefinitions({name: 'Post', nodeType: postType});

var settingType = new GraphQLObjectType({
  name: 'Setting',
  fields: {
    _id: {
      type: new GraphQLNonNull(GraphQLID)
    },
    id: globalIdField('Setting'),
    amount: {
      type: GraphQLString
    },
    all_posts: {
      type: postConnection,
      args: {
       ...connectionArgs,
        query: {type: GraphQLString}
      },
      resolve: (rootValue, args) => connectionFromPromisedArray(
        getAllPosts(rootValue, args),
        args
      ),
    },
  },
  interfaces: [nodeInterface]
});

var Root = new GraphQLObjectType({
  name: 'Root',
  fields: () => ({
    node: nodeField,
    setting: {
      type: settingType,
      args: {
         ...connectionArgs,
          currency: {type: GraphQLString}
        },
      resolve: (rootValue, args) => {
       return getSetting(args.currency).then(function(data){
        return data[0];
       }).then(null,function(err){
        return err;
       });
      }
    },
  })
});

下面是我的database.js

export function getAllPosts(params,args) {
  let findTitle = {};
  let findContent = {};
  if (args.query) {
    findTitle.title = new RegExp(args.query, 'i');
    findContent.content = new RegExp(args.query, 'i');
  }
  console.log("getAllPosts",args)
  return new Promise((resolve, reject) => {
      Post.find({$or: [findTitle,findContent]}).sort({createdAt: 'descending'}).exec({}, function(err, posts) {
        if (err) {
          resolve({})
        } else {
          resolve(posts)
        }
      });
  })
}

现在我想通过 $query 变量获取所有帖子所以鉴于我是这样写的

import React, { Component } from 'react';
import Relay from 'react-relay';

class BlogList extends Component {
  constructor(props) {
    super(props);
    this.state = {
      query: '',
    };
    this.handleSubmit = this.handleSubmit.bind(this);
  }

  handleSubmit(){
    this.props.relay.setVariables({query: this.state.query});
  }
  render() {
    return (

        <div className="input-group col-md-12">
            <input type="text" onChange={this.handleChange.bind(this,"query")} value={this.state.query} name="query" placeholder="Enter Title or content"/><br/>

            <span className="input-group-btn">
                <button type="button" onClick={this.handleSubmit} className="btn btn-info btn-lg">
                    <i className="glyphicon glyphicon-search"></i>
                </button>
            </span>
        </div>
    )
  }
};

export default Relay.createContainer(BlogList, {
  initialVariables: {
    query: ''
  },
  fragments: {
    viewer: () => Relay.QL`
      fragment on Setting {
        id,
        all_posts(first: 10000000,query: $query) {
          edges {
            node {
              id,
              _id,
              title,
              content,
              createdAt,
              username,
              color,
              images{
                full
              }
            }
          }
        }
      }
    `,
  },
});

在我的路线中

const SettingQueries = {
 viewer: () => Relay.QL`query{
  setting(currency: "USD")
 }`,
}
export default [{
  path: '/',
  component: App,
  queries: UserQueries,PostQueries,SettingQueries,
  indexRoute: {
    component: IndexBody,
  },
  childRoutes: [ 
  ,{
    path: 'settings',
    component: Setting,
    queries: SettingQueries,
  }]
}]

一切都在 /graphql 上进行

但是当我从网站搜索时它会生成响应错误

{
  "data": {
    "node": null
  },
  "errors": [
    {
      "message": "Abstract type Node must resolve to an Object type at runtime for field Root.node with value \"\",received \"null\".",
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ]
    }
  ]
}

因为我的网络浏览器正在发送如下请求

请告诉我我错过了什么？另外，如果我需要添加一些额外的信息，请告诉我。

Answer 1

问题可能出在您的 nodeDefinitions() 函数中。第一个回调，也命名为 idFetcher 必须 return 单个对象。但是，我在你的定义中看到你 return 一个集合

var { nodeInterface, nodeField } = nodeDefinitions(
  (globalId) => {
    var { type, id } = fromGlobalId(globalId);
    ...
    }else if (type === 'Post') {
      return getPosts(); // this should be getPost(id)
    }
);

这就是为什么您的下一个回调（称为 typeResolver 失败并且 return 将您设为 null 的原因。

var { nodeInterface, nodeField } = nodeDefinitions(
  ...
  (obj) => {
    ...
    // here you get Promise/Collection instead of single Post instance, therefore condition failed
    }else if (obj instanceof Post) {
      return postType;
    }
    return null;
  }
);

Answer 2

LordDave 的回答揭示了您的代码中的一个问题。正如您在他的回答中评论的那样，settingType 的 all_posts 字段无效。

如果您在数据库代码中使用了 mongoose 库，我发现您的查询有问题：

Post.find({$or: [findTitle,findContent]}).sort({createdAt: 'descending'}).exec({}, function(err, posts) {
  if (err) {
    resolve({})
  } else {
    resolve(posts)
  }
});

根据 exec 的文档，将您的查询更改为

return Post.find({$or: [findTitle,findContent]}).sort({createdAt: 'descending'}).exec(function(err, posts) {
  if (err) {
    resolve({})
  } else {
    resolve(posts)
  }
});

作为execreturns一个承诺，你甚至可以做到

return Post.find({$or: [findTitle,findContent]}).sort({createdAt: 'descending'}).exec();

Answer 3

最后我通过创建一个新类型 'postList' 并将其定义如下

使其工作

var { nodeInterface, nodeField } = nodeDefinitions(
  (globalId) => {
    var { type, id } = fromGlobalId(globalId);
    if (type === 'User') {
      return getUser(id);
    }else if (type==='postList') {
      return getpostList(id);
    } else{
      return null;
    }

  },
  (obj) => {
    if (obj instanceof User) {
      return userType;
    }else if (obj instanceof postList) {
      return postListType;
    }else{
      return null;
    }
  }
);

在database.js

class postList {}

postList.id = "Post_id";

export {postList}
export function getpostList(id) {
  return new postList
}

和下面的根字段

var postListType = new GraphQLObjectType({
  name: 'postList',
  description: 'List of posts',
  fields: () => ({
    id: globalIdField('postList'),
    posts: {
      type: postConnection,
      description: 'List of posts',
      args: {
       ...connectionArgs,
        query: {type: GraphQLString}
      },
      resolve: (_, args) => connectionFromPromisedArray(getAllPosts(_,args), args),
    },
  }),
  interfaces: [nodeInterface],
});

var Root = new GraphQLObjectType({
  name: 'Root',
  fields: () => ({
    node: nodeField,
    postList: {
      type: postListType,
      resolve:(rootValue)=> {
        return getpostList()
      }
    },
  })
});

Answer 4

我运行在使用 InterfaceType 时遇到了这个问题，并在我的 if-elseif-else 中的专门 ObjectType 之前检查了 InterfaceType TypeResolver

抽象类型节点必须在运行时解析为字段 Root.node 的对象类型，值为 \"\"，已收到 \"null\"。

Abstract type Node must resolve to an Object type at runtime for field Root.node with value \"\",received \"null\"."

node.js

reactjs

relayjs