前端怎么用 EventSource并配置请求头及加参数（流式数据）

本文主要是介绍前端怎么用 EventSource并配置请求头及加参数（流式数据），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

这里写目录标题

一、EventSourcePolyfill
二、直接上代码

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);};},