在Apollo Server中集成Neo4j图数据并正确返回关联节点

const { ApolloServer, gql } = require('apollo-server');
const neo4j = require('neo4j-driver');
const { GraphQLJSON } = require('graphql-scalars'); // 用于处理动态属性

const typeDefs = gql`
  scalar JSON # 定义一个JSON标量，用于存储不确定的属性集合

  # 定义公司类型
  type Company {
    id: ID!
    orgNo: String!
    companyName: String!
    address: String!
    city: String!
    zipCode: String!
    connectedNodes: [Node] # 关联节点列表
  }

  # 定义人员类型 (虽然在解决方案中作为Node返回，但可以根据需要扩展)
  type Person {
    id: ID!
    role: String
    ZipCode: String
    Street: String
    test_id: String
    label: String
    City: String
    RoleCode: String
    Name: String
  }

  # 定义一个通用的节点接口或类型，用于表示关联节点
  # 这里使用type Node，因为它足够灵活，可以通过properties字段包含不同节点的具体属性
  type Node {
    id: ID!
    labels: [String]!
    properties: JSON
  }

  # 定义查询类型
  type Query {
    company(orgNo: String!): Company # 根据组织编号查询公司
  }
`;

// Neo4j 驱动配置
const driver = neo4j.driver(
  'bolt://localhost:7687', // Neo4j 数据库地址
  neo4j.auth.basic('neo4j', 'password') // 认证信息
);

// Cypher 查询语句
// MATCH (source:Company {OrgNo: $orgNo}) 匹配中心公司节点
// OPTIONAL MATCH path = (source)-[*1..3]-(target) 可选匹配1到3跳的路径到目标节点
// WHERE NONE(rel IN relationships(path) WHERE rel.RoleCode IN ['REV', 'SU']) 过滤掉特定关系类型的路径
// RETURN source, COLLECT(DISTINCT target) AS connected_nodes 返回源节点和所有不重复的目标节点
const cypherQuery = `
  MATCH (source:Company {OrgNo: $orgNo})
  OPTIONAL MATCH path = (source)-[*1..3]-(target)
  WHERE NONE(rel IN relationships(path) WHERE rel.RoleCode IN ['REV', 'SU'])
  RETURN source, COLLECT(DISTINCT target) AS connected_nodes
`;

// 原始的 Query.company 解析器（存在问题）
const resolvers_problematic = {
  JSON: GraphQLJSON,
  Query: {
    company: async (_, { orgNo }) => {
      const session = driver.session();
      const result = await session.run(cypherQuery, { orgNo });
      await session.close();

      const companyNode = result.records[0]?.get('source')?.properties;
      if (!companyNode) return null;

      const connectedNodes = result.records[0]?.get('connected_nodes')?.map(record => {
        // 映射逻辑...
        return {
          id: record.identity?.toString() || null,
          labels: record.labels || [],
          properties: record.properties || {}
        };
      }) || [];

      const company = {
        id: companyNode && companyNode['identity']?.toString() || '',
        orgNo: companyNode && companyNode['OrgNo'] || null,
        companyName: companyNode && companyNode['CompanyName'] || null,
        address: companyNode && companyNode['Address'] || null,
        city: companyNode && companyNode['City'] || null,
        zipCode: companyNode && companyNode['ZipCode'] || ''
        // ⚠️ 问题所在：connectedNodes 在这里没有被添加到 company 对象中
      };
      return company;
    },
  },
};

const resolvers = {
  JSON: GraphQLJSON, // 注册JSON标量解析器

  Query: {
    company: async (_, { orgNo }) => {
      const session = driver.session();
      const result = await session.run(cypherQuery, { orgNo });
      session.close();

      const companyNode = result.records[0]?.get('source')?.properties;
      if (!companyNode) return null;

      // 映射 Neo4j 返回的关联节点数据到 GraphQL 的 Node 类型
      const connectedNodes = result.records[0]?.get('connected_nodes')?.map(record => {
        return {
          id: record.identity?.toString() || null, // Neo4j 内部ID
          labels: record.labels || [], // 节点的标签数组
          properties: record.properties || {} // 节点的所有属性
        };
      }) || [];

      // 构建最终的 company 对象，并包含 connectedNodes
      const company = {
        id: companyNode && companyNode['identity']?.toString() || '',
        orgNo: companyNode && companyNode['OrgNo'] || null,
        companyName: companyNode && companyNode['CompanyName'] || null,
        address: companyNode && companyNode['Address'] || null,
        city: companyNode && companyNode['City'] || null,
        zipCode: companyNode && companyNode['ZipCode'] || '',
        connectedNodes: connectedNodes // ? 关键：将关联节点附加到 company 对象
      };

      return company;
    },
  },

  // ? 关键：为 Company 类型的 connectedNodes 字段定义解析器
  // Apollo Server 会在解析 Company 对象的 connectedNodes 字段时调用此解析器
  // parent 参数就是 Query.company 解析器返回的 company 对象
  Company: {
    connectedNodes: async (parent) => parent.connectedNodes
  },
};

const server = new ApolloServer({
  typeDefs,
  resolvers,
});

server.listen().then(({ url }) => {
  console.log(`Server running at ${url}`);
});