希望有人可以帮助我解决这个小问题,我现在无法弄清楚。
问题陈述:
为了在我的 DataLoader
中进行身份验证,我想访问“上下文” .这个DataLoader
在单独的路径中定义 /loaders
.在我的 resolvers.js
我可以使用 dataSources.userAPI.getAllUsers()
很好地访问我的上下文.
但是如何在我的服务器端应用程序的其他任何地方访问它,比如 f.e.在我的/loaders
文件夹?
我只是不知道如何访问我的上下文对象然后将 token 传递给 DataLoader
然后从我的 API 加载数据,然后将此数据传递给我的 resolvers.js
文件。
非常感谢每一个帮助,我不知道如何解决这个简单的事情..谢谢!
代码如下:
index.js
const express = require('express');
const connectDB = require('./config/db');
const path = require('path');
var app = express();
const cors = require('cors')
const axios = require('axios')
// apollo graphql
const { ApolloServer } = require('apollo-server-express');
const DataLoader = require('dataloader')
const { userDataLoader } = require('./loaders/index')
// Connect Database
connectDB();
// gql import
const typeDefs = require('./schema');
const resolvers = require('./resolvers')
// apis
const UserAPI = require('./datasources/user')
// datasources
const dataSources = () => ({
userAPI: new UserAPI(),
});
// context
const context = ({ req, res }) => ({
token: req.headers.authorization || null,
loaders: {
userLoader: userDataLoader,
},
res
})
// init server
const server = new ApolloServer({
typeDefs,
resolvers,
dataSources,
context
});
// middleware
app.use(express.json());
// cors
var corsOptions = {
credentials: true
}
app.use(cors(corsOptions))
// serve middleware
server.applyMiddleware({
app
});
// run server
app.listen({ port: 4000 }, () =>
console.log(`Server ready at http://localhost:4000${server.graphqlPath}`)
);
module.exports = {
dataSources,
context,
typeDefs,
resolvers,
loaders,
ApolloServer,
UserAPI,
server,
};
装载机/index.js const userDataLoader = require('./user')
module.exports = {
userDataLoader
}
加载器/user.js const UserAPI = require('../datasources/users')
// init loader
const userDataLoader = new DataLoader(keys => batchUser(keys))
// batch
const batchUsers = async (keys) => {
// this part is not working!
// How to access the UserAPI methods in my DataLoader?
// Or lets say: How to access context from here,
// so I can add auth for the server I am requesting data from?
const userAPI = new UserAPI()
const users = userAPI.getAllUsers()
.then(res => {
return res.data
})
return keys.map(userId => users.find(user=> user._id === userId))
}
module.exports = userDataLoader
解析器.js // here is just my api call to get the data from my
// dataloader with userLoader.load() and this works perfectly
// if I just make API calls with axios in my loaders/user
// here just a little snippet from the resolver file
....
users: async (parent, args, { loaders }) => {
const { userLoader } = loaders
if (!parent.users) {
return null;
}
return await userLoader.load(parent.user)
},
....
数据源/user.js const { RESTDataSource } = require('apollo-datasource-rest');
class UserAPI extends RESTDataSource {
constructor() {
super()
this.baseURL = 'http://mybaseurl.com/api'
}
willSendRequest(request) {
request.headers.set('Authorization',
this.context.token
);
}
async getUserById(id) {
return this.get(`/users/${id}`)
}
async getAllUsers() {
const data = await this.get('/users');
return data;
}
}
module.exports = UserAPI;
最佳答案
我建议创建一个函数来创建数据加载器并在闭包内提供所需的状态,并且根本不使用数据源:
module.exports.createDataloaders = function createDataLoaders(options) {
const batchUsers = ids => {
const users = await fetch('/users/', { headers: { Authorization: options.auth } });
// ...
}
return {
userLoader: new Dataloader(batchUsers);
};
}
// now in index.js
// context
const context = ({ req, res }) => ({
token: req.headers.authorization || null,
loaders: createDataloaders({ auth: req.headers.authorization || null }),
res
})
// init server
const server = new ApolloServer({
typeDefs,
resolvers,
context
});
或者考虑翻转你的图层:const { RESTDataSource } = require('apollo-datasource-rest');
class UserAPI extends RESTDataSource {
constructor() {
super()
this.baseURL = 'http://mybaseurl.com/api'
this.dataloader = new Dataloader(ids => {
// use this.get here
});
}
willSendRequest(request) {
request.headers.set('Authorization',
this.context.token
);
}
async getUserById(id) {
return this.dataloader.load(id);
}
async getAllUsers() {
const data = await this.get('/users');
return data;
}
}
module.exports = UserAPI;
但是数据源并非设计为与 Dataloader 一起使用,如 here 所述在 Apollo 文档本身。因此,如果您想保留源代码,则可以一起摆脱加载器。基本上,他们所说的是,包装其余 API 的 GraphQL API 从(全局)请求缓存中受益更多,而不是从请求前数据加载器中受益。但是,跨请求缓存可能会导致授权问题,所以要小心。
关于javascript - Apollo 服务器 : How to access 'context' outside of resolvers in Dataloader from REST API Datasource,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/64157794/