前端对接fastGPT流式数据+打字机效果

本文主要是介绍前端对接fastGPT流式数据+打字机效果，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！

首先在对接api时参数要设置stream: true,

      const data = {chatId: 'abc',stream: true,//这里true返回流式数据detail: false,variables: {uid: 'sfdsdf',name: 'zhaoyunyao,'},messages: [{ content: text, role: 'user' }]};

不要用axios发请求不然处理不了流式数据我这里使用fetch

        const response = await fetch(`${url}`, {method: 'post',headers: headers,body: JSON.stringify(data)});const reader = response.body.getReader();//创建了一个读取器对象，用于从响应主体中读取数据。response.body 是一个 ReadableStream 对象，通过调用 getReader() 方法可以获取一个读取器对象，以便逐步读取响应的内容。// 循环读取响应流while (true) {const { done, value } = await reader.read();if (done) break;// 将ArrayBuffer转为文本const chunk = new TextDecoder('utf-8').decode(value);// 处理文本为json格式const jsonArr = chunk.trim().replace(/\n/g, '').split('data: ').splice(1)for (let index = 0; index < jsonArr.length; index++) {const json = jsonArr[index];try {if (JSON.parse(json).choices) {const text = JSON.parse(json).choices[0].delta.content ?? ''content += text.replace(/^\n/g, '')} else {content = "内部出了问题o(╥﹏╥)o"}} catch {// 处理转json不报错}}obj.content = content //这里的content就是最终输出的文本}

然后我们再加一个打字机的光标用html+css实现

              <div class="chat-item-details">{{ item.content }}/** 这里的span就是光标 **/<span class="cursor-blink" v-show="item.awaitReply">  </span></div>

再写上对应的css

              .cursor-blink {display: inline-block;height: 16px;margin-bottom: -3px;width: 2px;animation: blink 1s infinite steps(1, start);}/*这里设置动画blink*/@keyframes blink {0%,100% {background-color: #000;color: #aaa;}50% {background-color: #bbb;/* not #aaa because it's seem there is Google Chrome bug */color: #000;}}

最后呈现的效果

上图呈现的差不多是打字机的效果了不过呢但在传输过程中每次停顿后会跳出一串内容然后又停顿一会,阅读体验有些不流畅, 就像玩游戏时帧数低卡顿的感觉, 我们用一个队列让它逐字地展示出来,并且根据传输速度控制输出的速度

需要一个打字机队列
队列提供入队和消费功能
需要一个动态时间来控制文字输出

    // 打字机队列// 添加队列addQueue(str,obj) {obj.queue.push(...str.split(''))},// 消费队列consume(obj) {if (obj.queue.length > 0) {let str = obj.queue.shift()str && this.onConsume(str,obj)} else if (obj.isDone) {obj.consuming = falseclearTimeout(obj.timmer)obj.awaitReply = falsethis.scrollBottom()}},// 消费间隔time(obj) {let time = 1000 / obj.queue.lengthreturn time > 100 ? 100 : time},// 消费下一个next(obj) {this.consume(obj)obj.timmer = setTimeout(() => {if (obj.consuming) {this.next(obj)}}, this.time(obj))},start(obj) {obj.consuming = trueobj.isDone=falsethis.next(obj)},done(obj) {obj.isDone=true},onConsume(str,obj) {obj.content += str},

加了过后的效果

最后附上完整代码

export default {data() {return {key: "xxx",AppId: "xx",text: "",readonly: false,messages: [{ content: "您好，我是小环！请问需要什么帮助呢？", role: 'assistant', awaitReply: false },],userImg: this.$store.getters.avatar,username: this.$store.getters.nickname,awaitReply: false,timmer: null,obj: null,queue: [],consuming: false,isDone: false}},mounted() {const messageTextarea = document.getElementById('messageTextarea');messageTextarea.addEventListener('keydown', (event) => {// 如果按下的是回车键（Enter）if (event.key === 'Enter' && !event.ctrlKey) {event.preventDefault(); // 阻止默认的换行行为// 在这里可以添加发送消息的逻辑this.send();} else if (event.key === 'Enter' && event.ctrlKey) {const cursorPosition = messageTextarea.selectionStart; // 获取光标位置const textBeforeCursor = messageTextarea.value.substring(0, cursorPosition); // 获取光标前的文本const textAfterCursor = messageTextarea.value.substring(cursorPosition); // 获取光标后的文本messageTextarea.value = textBeforeCursor + '\n' + textAfterCursor; // 在光标位置插入换行符messageTextarea.selectionStart = cursorPosition + 1; // 设置光标位置为插入换行符后的位置messageTextarea.selectionEnd = cursorPosition + 1;}});},methods: {// 打字机队列// 添加队列addQueue(str, obj) {obj.queue.push(...str.split(''))},// 消费队列consume(obj) {if (obj.queue.length > 0) {let str = obj.queue.shift()str && this.onConsume(str, obj)} else if (obj.isDone) {obj.consuming = falseclearTimeout(obj.timmer)obj.awaitReply = falsethis.scrollBottom()}},// 消费间隔time(obj) {let time = 500 / obj.queue.lengthreturn time > 50 ? 50 : time},// 消费下一个next(obj) {this.consume(obj)obj.timmer = setTimeout(() => {if (obj.consuming) {this.next(obj)}}, this.time(obj))},start(obj) {obj.consuming = trueobj.isDone = falsethis.next(obj)},done(obj) {obj.isDone = true},onConsume(str, obj) {obj.content += str},async send() {if (this.text === "" || /^\s+$/.test(this.text)) {this.$message.warning('请输入内容')return}const text = this.textthis.text = ""const url = 'https://api.fastgpt.in/api/v1/chat/completions';this.messages.push({ role: 'user', content: text });let obj = { content: "", role: 'assistant', awaitReply: true, queue: [], consuming: false, isDone: false, timmer: null }this.messages.push(obj);this.scrollBottom()const data = {// 这里可以设置请求参数chatId: 'abc',stream: true,detail: false,variables: {uid: 'sfdsdf',name: 'zhaoyunyao,'},messages: [{ content: text, role: 'user' }]};const headers = {// 这里可以设置请求头Authorization: `Bearer ${this.key}`,"Content-Type": "application/json"};try {const response = await fetch(`${url}`, {method: 'post',headers: headers,body: JSON.stringify(data)});const reader = response.body.getReader();//let content = ""// 开始打字机队列this.start(obj)// 循环读取响应流while (true) {const { done, value } = await reader.read();if (done) break;// 将ArrayBuffer转为文本const chunk = new TextDecoder('utf-8').decode(value);// 处理文本为json格式const jsonArr = chunk.trim().replace(/\n/g, '').split('data: ').splice(1)for (let index = 0; index < jsonArr.length; index++) {const json = jsonArr[index];try {if (JSON.parse(json).choices) {const text = JSON.parse(json).choices[0].delta.content ?? ''this.addQueue(text.replace(/^\n/g, ''), obj)} else {this.addQueue('内部出了问题o(╥﹏╥)o', obj)}} catch {// 处理转json不报错}}this.scrollBottom()}} catch (error) {console.error('请求错误:', error);}this.done(obj)},// 滚到最底部scrollBottom() {setTimeout(() => {const mainChat = this.$refs.mainChatmainChat.scrollTop = mainChat.scrollHeight}, 0)},}
}