Knex 查询 .where() 在 GraphQL 中返回 null

Question

我正在尝试使用 knex 和 apollo 服务器构建一个简单的 api，该服务器正在运行，但使用 where 的查询返回 null

服务器

import { ApolloServer } from 'apollo-server'
import knex from './knex'
import { resolvers, typeDefs } from './schema'
import { UserSQLDataSource } from './schema/users/datasource'

const server = new ApolloServer({
  typeDefs,
  resolvers,
  dataSources: () => {
    return {
      userDb: new UserSQLDataSource(knex),
    }
  },
  uploads: false,
  cors: {
    origin: ['https://studio.apollographql.com'],
    credentials: true,
  },
})

server.listen(4003).then(({ url }) => {
  console.log(`Server listening on url ${url}`)
})

膝盖指数

const knexFn = require('knex')
const knexfile = require('./knexfile')
const knex = knexFn(knexfile[process.env.NODE_ENV])
module.exports = knex

knex 文件

const dotenv = require('dotenv').config()

module.exports = {
  development: {
    client: process.env.DB_CLIENT,
    connection: {
      database: process.env.DB_NAME,
      user: process.env.DB_USER,
      password: process.env.DB_PASS,
    },
    pool: {
      min: 2,
      max: 10,
    },
    migrations: {
      tableName: process.env.MIGRATION_NAME,
    },
  },
}

数据源

import { DataSource } from 'apollo-datasource'
import { InMemoryLRUCache } from '@apollo/utils.keyvaluecache'
import DataLoader from 'dataloader'

export class SQLDatasource extends DataSource {
  constructor(knex, tableName) {
    super()
    this.db = knex
    this.tableName = tableName
    this._loader = new DataLoader(async ids => this.batchLoaderCallback(ids))
  }

  initialize({ context, cache }) {
    this.context = context
    this.cache = cache || new InMemoryLRUCache()
  }

  async batchLoad(id) {
    return this._loader.load(id)
  }

  async batchLoaderCallback(_ids) {
    return _ids
  }
}

带有查询 getUser 日志的用户数据源

import { SQLDatasource } from '../../schema/datasources'

export class UserSQLDataSource extends SQLDatasource {
  constructor(knex) {
    super(knex, 'users')
  }

  async getUsers() {
    return await this.db(this.tableName)
  }

  async getUser(id) {
    try {
      const query = this.db(this.tableName).where({ id: id })
      console.log(query.toSQL())

      return await query
    } catch (error) {
      console.error(error)
      throw error
    }
  }
}

查询日志

Server listening on url http://localhost:4003/
{
  method: 'select',
  options: {},
  timeout: false,
  cancelOnTimeout: false,
  bindings: [ '1' ],
  __knexQueryUid: 'sH05Z4l3pgdNm5mY9YPkeu6',
  sql: 'select * from `users` where `id` = ?'
}

用户类型定义

import { gql } from 'apollo-server'

export const userTypeDefs = gql`
  extend type Query {
    user(id: ID!): User!
    users: [User!]!
  }

  type User {
    id: ID!
    firstName: String!
    lastName: String!
    userName: String!
    email: String!
    password_hash: String!
    token: String!
    createdAt: String!
    updatedAt: String!
  }
`

用户解析器

const users = async (_, { input }, { dataSources }) => {
  const users = await dataSources.userDb.getUsers(input)
  return users
}

const user = async (_, { id }, { dataSources }) => {
  const user = await dataSources.userDb.getUser(id)
  return user
}

export const userResolvers = {
  Query: { user, users },
}

不带where的查询，所有用户，返回ok，带where的查询，使用id作为参数，或更改为其他列（名字，电子邮件等）总是返回null。

我对查询做了一些更改，更改了参数，结果相同。我不知道当前版本的所有组件是否有问题，package.json是这样的

{
  "name": "mysql",
  "version": "1.0.0",
  "description": "",
  "main": "src/index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "sucrase": "./src -d ./Dir --transforms imports",
    "knex": "npx knex --cwd ./src/knex",
    "knex-h": "npx knex --help",
    "dev": "nodemon -e js src/index.js"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "apollo-server": "^3.12.0",
    "dataloader": "^2.2.2",
    "datasource-sql": "^2.1.0",
    "dotenv": "^16.3.1",
    "graphql": "^16.8.0",
    "knex": "^2.5.1",
    "mysql2": "^3.6.0",
    "path": "^0.12.7"
  },
  "devDependencies": {
    "eslint": "^8.47.0",
    "eslint-config-prettier": "^9.0.0",
    "eslint-plugin-prettier": "^5.0.0",
    "nodemon": "^3.0.1",
    "prettier": "^3.0.2",
    "sucrase": "^3.34.0"
  }
}

Answer 1

当我第一次开始使用 knex 和 Apollo 时，我也遇到了这个问题。

查询例如：

const user = await dataSources.userDb.getUser(id);

返回长度为 1 的用户的数组。但是您的 GraphQL 查询正在寻找单个用户。

这里有两个简单的模式可以解决这个问题：

1. const [user] = await dataSources.userDb.getUser(id);

2. const user = await dataSources.userDb.getUser(id).first()

   ；