使用apollo和express的全局变量

const { ApolloServer, gql } = require('apollo-server');
const express = require('express');

const app = express();

// 定义GraphQL类型和解析器
const typeDefs = gql`
  type Query {
    hello: String
  }
`;

const resolvers = {
  Query: {
    hello: (_, __, context) => {
      // 在解析器中访问全局变量
      const globalVariable = context.globalVariable;
      return `Hello, ${globalVariable}!`;
    },
  },
};

// 创建Apollo服务器
const server = new ApolloServer({
  typeDefs,
  resolvers,
  context: ({ req }) => {
    // 在上下文中传递全局变量
    return {
      globalVariable: 'World',
    };
  },
});

// 将Apollo服务器应用于Express应用程序
server.applyMiddleware({ app });

// 启动Express服务器
app.listen({ port: 3000 }, () =>
  console.log(`Server ready at http://localhost:3000${server.graphqlPath}`)
);

const express = require('express');
const app = express();

// 设置全局变量
app.set('globalVariable', 'Hello, World!');

// 在路由处理程序中访问全局变量
app.get('/', (req, res) => {
  const globalVariable = req.app.get('globalVariable');
  res.send(globalVariable);
});

app.listen(3000, () => {
  console.log('Server started on port 3000');
});