如何将 graphql-compose-mongoose 与 next.js apollo 服务器集成答案

【问题标题】：How to integrate graphql-compose-mongoose with next.js apollo server如何将 graphql-compose-mongoose 与 next.js apollo 服务器集成
【发布时间】：2021-03-29 11:34:01
【问题描述】：

我正在尝试在我的项目中使用 mongoose、graphql 和 next.js，但不断收到此错误：

Error: You try to generate GraphQL Type with name Customer from mongoose model but this type already exists in SchemaComposer. Please choose another type name "composeWithMongoose(model, { name: 'NewTypeName' })", or reuse existed type "schemaComposer.getOTC('TypeName')", or remove type from SchemaComposer before calling composeWithMongoose method "schemaComposer.delete('TypeName')".

我拥有的是简单的猫鼬模式：

const mongoose = require('mongoose');

const CustomerSchema = new mongoose.Schema({
    name: {
        type: String
    }
}, {
    toJSON: {
        transform: function (doc, ret, options) {
            ret.id = ret._id.toString();
            delete ret.__v;
            delete ret._id;
        }
    }
});

以及组成 gql 架构的单独模块：

import {composeMongoose} from "graphql-compose-mongoose";

import { schemaComposer } from 'graphql-compose';

import {Customer} from '../db/models/Customer';

const customizationOptions = {}
const CustomerTC = composeMongoose(Customer, customizationOptions);

schemaComposer.Query.addFields({
    customerById: CustomerTC.mongooseResolvers.findById()
})

console.log("Schema:", schemaComposer.getOTC('Customer'))

const customerSchema = schemaComposer.buildSchema();
export default customerSchema;

和服务器 api 模块：

import {ApolloServer} from 'apollo-server-micro'
import customerSchema from '../../apollo/customer-type-defs';

const apolloServer = new ApolloServer({
    schema: customerSchema,
    context: () => ({})
});

export const config = {
    api: {
        bodyParser: false,
    },
}

export default apolloServer.createHandler({path: '/api/graphql'})

有人可以告诉我如何修复错误吗？

【问题讨论】：

标签： mongoose graphql next.js apollo-server

【解决方案1】：

我遇到了同样的问题，我发现解决方案只是检查ObjectTC 是否已经存在，如果不存在则创建。

function createObjectTC({ model, customizationOptions = {} }}) {
 let ModelTC = null;

 try {
  ModelTC = schemaComposer.getOTC(model.modelName);
 } catch {
  ModelTC = composeWithMongoose(model, customizationOptions);
 }

 return ModelTC;
}


const UserTC =  createObjectTC({ model: User, customizationOptions: {} });

【讨论】：

【解决方案2】：

我的解决方案是使用 graphql 和 express 创建一个单独的后端服务器。以及一个前端服务器，以保留下一个服务器引擎提供的所有内置优势。 hack 是设置一个 api/graphql 端点，将 graphql 调用转发到后端服务器。

这是我的 api 端点：

/api/graphql.js

import logger from '../../lib/logger'
import {getSession} from "next-auth/client";


export default async (_req, _res) => {
    // logger.debug("api/graphql: Request body:\n", _req.body)
    const session = await getSession({req: _req})
    logger.debug( "current session: ", session )
    const accessToken = session?.accessToken ?? "";
    const query = {
        method: 'POST', // *GET, POST, PUT, DELETE, etc.
        mode: 'cors', // no-cors, *cors, same-origin
        cache: 'no-cache', // *default, no-cache, reload, force-cache, only-if-cached
        credentials: 'same-origin', // include, *same-origin, omit
        headers: {
            'Content-Type': 'application/json',
            'infraToken': session.infraToken
            // 'Content-Type': 'application/x-www-form-urlencoded',
        },
        redirect: 'follow', // manual, *follow, error
        referrerPolicy: 'no-referrer', // no-referrer, *no-referrer-when-downgrade, origin, origin-when-cross-origin, same-origin, strict-origin, strict-origin-when-cross-origin, unsafe-url
        body: JSON.stringify({
            operationName: _req.body.operationName,
            variables: _req.body.variables,
            query: _req.body.query
        }) // body data type must match "Content-Type" header
    };
    const res = await fetch('http://localhost:4000/api/graphql', query)
    const json = await res.json()
    _res.statusCode = 200;
    _res.setHeader('Content-Type', 'application/json');
    _res.setHeader('Cache-Control', 'max-age=180000');
    _res.json(json)
    _res.end()
};

我还有其他端点来处理其他操作，例如图像上传和获取。并分别认证下 /api/rest/[...rest].js 和 /api/auth/[...nextauth].js

【讨论】：