前端怎么用 EventSource并配置请求头及加参数（流式数据）

这里写目录标题

EventSource 接口是 web 内容与服务器发送事件通信的接口。
一个 EventSource 实例会对 HTTP 服务器开启一个持久化的连接，以 text/event-stream 格式发送事件，此连接会一直保持开启直到通过调用 EventSource.close() 关闭。
EventSource 服务器发送事件是单向的。数据消息只能从服务端发送到客户端。

一、EventSourcePolyfill

EventSourcePolyfill 是EventSource封装的一个方法，EventSourcePolyfill 可以配置请求头

// 安装 npm install event-source-polyfill --save//引用import { EventSourcePolyfill } from "event-source-polyfill";

二、直接上代码

 sendRequest(messageId, content, questionId, questionType) {      const innerIndex = this.messageList.length - 1;      const aiToken = JSON.parse(localStorage.getItem('token'));      let that = this;      let eventSource;      if (questionId) {        eventSource = new EventSourcePolyfill(          `${            process.env.VUE_APP_WEB_API          }/url...........?f_rnd=${new Date().getTime()}&message_id=${messageId}&question_id=${questionId}&stream=true`,          {            headers: {              'Content-Type': 'text/event-stream',              aiToken: aiToken,              accept: '*/*',              'Cache-Control': 'no-cache',              Connection: 'keep-alive',              // 'cache-control': 'max-age=0',            },          }        );      } else {        eventSource = new EventSourcePolyfill(          `${            process.env.VUE_APP_WEB_API          }/ai_assistant_chatdoc/receive_message?f_rnd=${new Date().getTime()}&message_id=${messageId}&stream=true`,          {            headers: {              'Content-Type': 'text/event-stream',              aiToken: aiToken,              accept: '*/*',              'Cache-Control': 'no-cache',              Connection: 'keep-alive',            },          }        );      }      //open：订阅成功（和后端连接成功）      eventSource.onopen = function (e) {        console.log(e, '连接刚打开时触发');      };      //message：后端返回信息，格式可以和后端协商      that.messageQueue = []; //整个流式数据      this.processing = false; //判断是否返回数据中      let resultWord = '';      let rowData = {};      eventSource.onmessage = function (e) {        const data = JSON.parse(e.data) || {}; //这里后端返回的是字符串所以目前我这边有转换        console.log(data, data.data.content, Date.now());        if (data.code === 200) {          that.loading = false;          that.scrollFlag = false;          if (data.data.content === '[DONE]') { //流式结束了            rowData = data.data;          }          that.messageQueue.push(data.data.content);          if (that.processing) return;          that.processing = true;           (async function processMessages() {            while (that.processing) {              // 改为无限循环              let message;              if (that.messageQueue.length > 0) {                message = that.messageQueue.shift();                if (message === '[DONE]') {                  that.receiveMsg.source = rowData.source;                  that.receiveMsg.sourceEdit = rowData.is_edit;                  that.$set(that.messageList[innerIndex], 'message_id', rowData.message_id);                  that.requestRecomme(messageId, innerIndex);                } else {                  resultWord += message;                  console.log(resultWord, 'resultWord');                  that.$set(that.messageList, innerIndex, {                    type: 'right',                    session_id: data.data.session_id,                    message_id: data.data.message_id,                    reply_id: data.data.reply_id,                    message: resultWord,                    source: [],                    sourceEdit: [],                    question: [],                  });                  that.receiveMsg = that.messageList[innerIndex];                  that.chcekScroll();                  that.executeScroll(!that.scrollFlag);                }                await new Promise(resolve => setTimeout(resolve, 30)); //30毫秒读取一下message              } else {                that.processing = false;                await new Promise(resolve => setTimeout(resolve, 800)); //如果读取速度大于流式返回速度就等一下              }              if (that.messageQueue.length === 0 && message === '[DONE]') {                break;              }            }            that.processing = false;          })();        }      };      //  error：错误（可能是断开，可能是后端返回的信息）      eventSource.onerror = function (e) {        console.log(e, '连接无法打开时触发');        eventSource.close(); // 关闭连接        setTimeout(() => {}, 5000);      };    },

链接: https://blog.csdn.net/weixin_49066399/article/details/138713416