TypeError [ERR_INVALID_ARG_TYPE]：“字符串”参数必须是字符串类型或 Buffer 或 ArrayBuffer 的实例。收到未定义

Question

我正在尝试使用 graphql 设置我的 koa 服务器，我这样做的方式是为路由“graphql”传递中间件，但我得到了标题中所述的错误。 我不确定为什么它以未定义的形式返回 _graphql。

这是我的 app.js 文件，它定义了服务器和服务器期望的路由。其中之一是我计划最初测试的 graphql 路线。

app.js

class Server {
  constructor(_config) {
    this.middleware = new Middleware(_config)
    this.knex = Knex({
      client: "mysql2",
      connection: {
        host: config.mysql.host,
        user: config.mysql.user,
        password: config.mysql.password,
        database: config.mysql.database,
        port: config.mysql.port || 3306,
        ssl: config.mysql.ssl || false,
      },
      pool: { min: 0, max: 20 },
    })

    // Tracker middleware
    let middleware = new Middleware({
      knex: this.knex,
      config: _config,
    })

    // define router
    const router = new Router()

    router.all("/graphql", middleware.graphql.bind(middleware), (ctx) => {
      ctx.body = ctx.graphql
    })

    app.use(router.routes()).use(router.allowedMethods())

    app.silent = false
    app.on("error", (err, ctx) => {
      // TODO: // Log error
      console.log(err)
      ctx.status = 500
      ctx.body = {
        message: err.message,
        status: err.statusCode,
        type: err.type || "UNDEFINED",
        info: err.info,
      }
    })
  }
}

index.js

这是在它自己的文件中定义的所有中间件的文件，但是中间件是通过 koa 的

ctx

传递下来的。

import { Cars } from "../models/cars.js"
import { Parkings } from "../models/parkings.js"
import { Transactions } from '../models/transactions.js'
import { CarInputSchema, ParkingInputSchema, TransactionInputSchema } from "./schema.js"
import { graphqlHTTP } from 'koa-graphql'
import { CarType, ParkingType, TransactionsType } from './graphql-schema.js'
import { GraphQLObjectType, GraphQLNonNull, GraphQLString, GraphQLInt, GraphQLID } from "graphql"

class Middleware {
  constructor(params) {
    this.knex = params.knex
    this.car = new Cars(params)
    this.parkings = new Parkings(params)
    this.transactions = new Transactions(params)
  }

  async graphql(ctx, next) {
    const schema = {
      query: new GraphQLObjectType({
        name: "Query",
        fields: {
          cars: {
            type: CarType,
            args: {
              id: { type: GraphQLID },
            },
            resolve: (root, args, ctx, info) => {
              const { id } = args
              return this.car.getById(id)
            },
          },
        },
      }),
    }

    
    ctx.graphql = await graphqlHTTP({
      schema:schema,
      graphiql: true,
    })

    await next()
  }

my car schema 在

graphql-schema.js

中定义

const CarType = new GraphQLObjectType({
  name: "Car",
  fields: () => ({
    id: { type: new GraphQLNonNull(GraphQLString), resolve: (root, args, context, info) => root.id },
    createAt: { type: GraphQLString },
    updatedAt: { type: GraphQLString },
    inactiveAt: { type: GraphQLString },
    fbUserId: { type: GraphQLString, resolve: (root, args, context, info) => root.fbUserId },
    carPlate: { type: GraphQLString, resolve: (root, args, context, info) => root.carPlate },
    carInfo: { type: GraphQLString, resolve: (root, args, context, info) => root.carInfo },
  }),
})

export { CarType }