Question

我当前正在使用ApolloClient连接到AppSync GraphQL API。对于查询和变异，这一切都非常有效，但是在使订阅生效时遇到了一些麻烦。我关注了Apollo文档，我的App.js如下所示：

import React from 'react';
import './App.css';
import { ApolloClient } from 'apollo-client';
import { ApolloProvider } from '@apollo/react-hooks';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { ApolloLink, split } from 'apollo-link';
import { WebSocketLink } from 'apollo-link-ws';
import { getMainDefinition } from 'apollo-utilities';
import { createAuthLink } from 'aws-appsync-auth-link';
import { createHttpLink } from 'apollo-link-http';
import AWSAppSyncClient, { AUTH_TYPE } from "aws-appsync";
import { useSubscription } from '@apollo/react-hooks';
import { gql } from 'apollo-boost';

const url = "https://xxx.appsync-api.eu-west-2.amazonaws.com/graphql"
const realtime_url = "wss://xxx.appsync-realtime-api.eu-west-2.amazonaws.com/graphql"
const region = "eu-west-2";
const auth = {
  type: AUTH_TYPE.API_KEY,
  apiKey: process.env.REACT_APP_API_KEY
};

const wsLink = new WebSocketLink({
  uri: realtime_url,
  options: {
    reconnect: true
  },
});

const link = split(
  // split based on operation type
  ({ query }) => {
    const definition = getMainDefinition(query);
    return (
      definition.kind === 'OperationDefinition' &&
      definition.operation === 'subscription'
    );
  },
  ApolloLink.from([
     createAuthLink({ realtime_url, region, auth }), 
     wsLink
  ]),
  ApolloLink.from([
     createAuthLink({ url, region, auth }), 
     createHttpLink({ uri: url })
  ])
);

const client = new ApolloClient({
  link: link,
  cache: new InMemoryCache({
    dataIdFromObject: object => object.id,
  }),
});

function Page() {
  const { loading, error, data } = useSubscription(
    gql`
      subscription questionReleased {
        questionReleased {
          id
          released_date
        }
      }
    `
  )

  if (loading) return <span>Loading...</span>
  if (error) return <span>Error!</span>
  if (data) console.log(data)

  return (
    <div>{data}</div>
  );
}

function App() {
  return (
    <ApolloProvider client={client}>
      <div className="App">
        <Page />
      </div>
    </ApolloProvider>
  );
}

export default App;

如果我转到Web检查器中的“网络”标签，则可以看到请求：

wss://xxx.appsync-realtime-api.eu-west-2.amazonaws.com/graphql

消息：

{"type":"connection_init","payload":{}}
{"id":"1","type":"start","payload":{"variables":{},"extensions":{},"operationName":"questionReleased","query":"subscription questionReleased {\n  questionReleased {\n    id\n    released_date\n    __typename\n  }\n}\n"}}
{"id":"2","type":"start","payload":{"variables":{},"extensions":{},"operationName":"questionReleased","query":"subscription questionReleased {\n  questionReleased {\n    id\n    released_date\n    __typename\n  }\n}\n"}}
{"payload":{"errors":[{"message":"Both, the \"header\", and the \"payload\" query string parameters are missing","errorCode":400}]},"type":"connection_error"}

我进行了很多搜索，似乎ApolloClient可能与AppSync订阅不兼容-有人可以确认吗？

因此，我尝试使用AWSAppSyncClient进行订阅：

function Page() {
  const aws_client = new AWSAppSyncClient({
    region: "eu-west-2",
    url: realtime_url,
    auth: {
      type: AUTH_TYPE.API_KEY,
      apiKey: process.env.REACT_APP_API_KEY
    },
    disableOffline: true
  });

  const { loading, error, data } = useSubscription(
    gql`
      subscription questionReleased {
        questionReleased {
          id
          released_date
        }
      }
    `,
    {client: aws_client}
  )

  if (loading) return <span>Loading...</span>
  if (error) return <span>Error!</span>
  if (data) console.log(data)

  return (
    <div>{data}</div>
  );
}

它现在发送带有请求的查询字符串：

wss://xxx.appsync-realtime-api.eu-west-2.amazonaws.com/graphql?header=eyJob3N0I...&payload=e30=

现在我得到了另一个错误：

{"type":"connection_init"}
{"payload":{"errors":[{"errorType":"HttpNotFoundException"}]},"type":"connection_error"}

我已经仔细检查了网址，没关系（如果不是，您会得到ERR_NAME_NOT_RESOLVED）。当我通过AppSync控制台手动运行该订阅时，该订阅即可工作，因此也可以。

我也在.hydrated()上尝试过aws_client，但又遇到了另一个错误（TypeError: this.refreshClient(...).client.subscribe is not a function）

我在做什么错？这几天让我发疯了！

Answer 1

发布后不久，我终于知道了。我将把解决方案放在这里，以防其他人遇到相同的问题。首先，AWSAppSyncClient应该使用主graphql url而不是实时url-它可以计算出实时url本身。但是，仅通过调用useSubscription，我仍然无法使用aws_client.subscribe()钩子来完成此工作。

为了使其与useSubscription钩一起使用，我找到了本讨论中提到的解决方案： https://github.com/awslabs/aws-mobile-appsync-sdk-js/issues/450

具体来说： https://github.com/awslabs/aws-mobile-appsync-sdk-js#using-authorization-and-subscription-links-with-apollo-client-no-offline-support

在React中使用ApolloClient进行AppSync订阅

1 个答案: