使用Express-GraphQL和React-Apollo进行GraphQL订阅

我跟随Apollo的文档在客户端和服务器上设置了GraphQL订阅，虽然我90％在那里，但我无法弄清楚如何设置订阅 Channels 以及如何将突变连接到这些 Channels 以便每当发生突变时，服务器将新数据推送到客户端 . （对于内容，我正在制作Reddit克隆，其中人们发布主题，其他人对其进行评论 . 因此，当您看到“主题”或“主题列表”时，请将其视为帖子 . ）

到目前为止，我已成功为订阅设置了Apollo Client：

const wsClient = new SubscriptionClient('ws://localhost:3001/subscriptions', {
  reconnect: true
});

const networkInterface = createNetworkInterface({
    uri: '/graphql',
    opts: {
        credentials: 'same-origin'
    }
});

const networkInterfaceWithSubscriptions = addGraphQLSubscriptions(
  networkInterface,
  wsClient,
);

const client = new ApolloClient({
    networkInterface: networkInterfaceWithSubscriptions,
    dataIdFromObject: o => o.id
});

我也为订阅设置了后端 . 这是我的server.js文件：

//===========================================================
//Subscription Managaer
//===========================================================
const pubsub = new PubSub();
const subscriptionManager = new SubscriptionManager({
  schema: schema,
  pubsub: pubsub
});

//=====================================
//WebSocket + Express Server
//=====================================

const server = createServer(app);

//setup listening port
server.listen(3001, ()=>{
    new SubscriptionServer(
    {
        subscriptionManager: subscriptionManager,
        onConnect: (connectionParams, webSocket) => {
            console.log('Websocket connection established');
        },
        onSubscribe: (message, params, webSocket) => {
            console.log("The client has been subscribed", message, params);
        },
        onUnsubsribe: (webSocket) => {
            console.log("Now unsubscribed");
        },
        onDisconnect: (webSocket) => {
            console.log('Now disconnected');
        }
    }, 
    {
        server: server,
        path: '/subscriptions',
    });
    console.log('Server is hot my man!');
})

我知道这些都是成功的，因为我在终端中记录了“Websocket connection established”消息 .

接下来是实际订阅 - 我创建了一个订阅模式类型（就像查询和突变一样）：

const SubscriptionType = new GraphQLObjectType({
    name: 'Subscription',
    fields: () => ({
        topicAdded: {
            type: TopicType,
            args: {repoFullName: {type: GraphQLString}}, //I don't understand what repoFullName is - I was trying to follow the Apollo docs, but they never specified that
            resolve(parentValue, args){
                return parentValue;
            }

        }
    })
});

module.exports = SubscriptionType;

并将其合并到我的根模式中 . 所以当我查看GraphiQL时，我看到：这个订阅在Docs侧面菜单中可用My GraphiQIL UI showing the subscriptionSchema successfully

在我的React组件中，我使用Apollo的subscribeToMore方法成功“订阅”它：

const TOPICS_SUBSCRIPTION = gql`
    subscription OnTopicAdded($repoFullName: String){
        topicAdded(repoFullName: $repoFullName){
            id
        }
    }
`;

class TopicList extends Component {
    componentDidMount() {
        this.createMessageSubscription = this.props.data.subscribeToMore({
          document: TOPICS_SUBSCRIPTION,
          // updateQuery: (previousState, {subscriptionData}) => {
          //   const newTopic = subscriptionData.data.Topic.node
          //   const topics = previousState.findTopics.concat([newTopic])
          //   return {
          //     findTopics: topics
          //   }
          // },
          onError: (err) => console.error(err)
        })

      } //...

我将“客户端已订阅”消息记录到我的终端中 . 但这就是我被困住的地方 . 我已经阅读了SubscriptionManager的SetupFunction，但这并没有包含在Apollo的文档中 . 我找不到如何将'createTopic'变异映射到此订阅，以便每当有人添加新主题时，它会弹出TopicList .

我意识到这真的很长，但我一直在拉扯我的头发以确定下一步是什么 . 任何帮助将非常感激！！谢谢你的阅读！