使用 ApolloClient 和 Apollo-Server-Express 处理 GraphQL 错误答案

【问题标题】：GraphQL Error Handling with ApolloClient and Apollo-Server-Express使用 ApolloClient 和 Apollo-Server-Express 处理 GraphQL 错误
【发布时间】：2018-10-21 17:26:26
【问题描述】：

apollo-link-error 的 onError 函数有一个填充的 graphQLErrors 对象，但是当 ApolloClient 抛出一个错误对象时，graphQLErrors 属性包含一个空数组。进一步检查显示 error.networkError.result.errors 中的 graphql 错误消息。

如何正确配置 Apollo 客户端以返回填充的 graphQLErrors 对象？

Apollo 客户端设置：

const {ApolloClient} = require('apollo-client')
const { ApolloLink } = require('apollo-link')

const {HttpLink} = require('apollo-link-http')
const {onError} = require('apollo-link-error')
const {InMemoryCache} = require('apollo-cache-inmemory')

const errorLink = onError(({ graphQLErrors, networkError }) => {
  if (graphQLErrors) {
    graphQLErrors.map(({ message, locations, path }) =>
      console.log(
        `[GraphQL error]: Message: ${message}, Location: ${locations}, Path: ${path}`,
      ),
    )
  }

  if (networkError) console.log(`[Network error]: ${networkError}`)
})

const middleware = (req, ignored_res, next) => {
  const client = new ApolloClient({
    link: ApolloLink.from([errorLink, new HttpLink({ uri:'http://somegraphqlserver.com', fetch: require('node-fetch') })]),
    cache: new InMemoryCache(),
  })

  req.GQLClient = client

  return next()
}

module.exports = middleware

调用 apollo-server-express：

req.GQLClient
    .query({
      query: SOME_MALFORMED_QUERY,
    })
    .then((data) => {...})
    .catch((error) => {
      console.log('rawError', error)
      console.log('error.networkError.result.errors', error.networkError.result.errors)
      return next(error)
    })

控制台结果：

[GraphQL error]: Message: Cannot query field "blah" on type "CustomerList"., Location: [object Object], Path: undefined
[Network error]: Error: Response not successful: Received status code 400


 rawError { Error: Network error: Response not successful: Received status code 400
   at new ApolloError (/.../node_modules/apollo-client/bundle.umd.js:121:28)
   at /.../node_modules/apollo-client/bundle.umd.js:1187:41
   at /.../node_modules/apollo-client/bundle.umd.js:1620:17
   at Array.forEach (<anonymous>)
   at /.../node_modules/apollo-client/bundle.umd.js:1619:18
   at Map.forEach (<anonymous>)
   at QueryManager.broadcastQueries (/.../node_modules/apollo-client/bundle.umd.js:1614:22)
   at /.../node_modules/apollo-client/bundle.umd.js:1114:31
   at process._tickCallback (internal/process/next_tick.js:178:7)
 graphQLErrors: [],
 networkError: 
  { Error: Response not successful: Received status code 400
   at throwServerError (/.../node_modules/apollo-link-http-common/lib/bundle.umd.js:33:21)
   at /.../node_modules/apollo-link-http-common/lib/bundle.umd.js:58:17
   at process._tickCallback (internal/process/next_tick.js:178:7)
    response: 
     Response {
       size: 0,
       timeout: 0,
       [Symbol(Body internals)]: [Object],
       [Symbol(Response internals)]: [Object] },
    statusCode: 400,
    result: { errors: [Array] } },
 message: 'Network error: Response not successful: Received status code 400',
 extraInfo: undefined }


error.networkError.result.errors [ { message: 'Cannot query field "blah" on type "CustomerList".',
   locations: [ [Object] ] } ]

库版本：

服务器：

"apollo-server-express": "^1.3.2"

客户：

"apollo-cache-inmemory": "^1.1.12"
"apollo-client": "^2.2.8"
"apollo-link-error": "^1.0.9"
"apollo-link-http": "^1.5.4"

【问题讨论】：

还开了一个github问题：github.com/apollographql/apollo-client/issues/3441
请注意，这种中间件方法在每次请求时都会重新创建 ApolloClient，因此缓存在这里毫无意义。

标签： node.js express graphql apollo-client apollo-server

【解决方案1】：

这是设计使然。来自docs：

graphQLErrors：来自 GraphQL 端点的错误数组

networkError：链接执行或服务器响应期间的任何错误，未作为 GraphQL 结果中的错误字段的一部分提供

换句话说，如果您的查询格式不正确，您请求的字段无效（例如在您的示例中），或者遇到导致状态不是 200 的任何其他问题，则该错误将显示为networkError 财产。另一方面，如果请求返回 200，但响应中的错误数组已填充，则相同的错误将作为 graphQLErrors 的一部分返回。

如果您想查看填充 graphQLErrors 的示例，请正确格式化您的查询，但让您的解析器在调用时立即抛出错误。只要查询没有遇到任何其他问题，您应该会在 graphQLErrors 中看到相同的错误弹出。

【讨论】：