feat: gpt3流响应

src/pages/api/chat/gpt3.ts

@@ -1,20 +1,38 @@
-// Next.js API route support: https://nextjs.org/docs/api-routes/introduction
 import type { NextApiRequest, NextApiResponse } from 'next';
-import { jsonRes } from '@/service/response';
+import { createParser, ParsedEvent, ReconnectInterval } from 'eventsource-parser';
 import { connectToDatabase } from '@/service/mongo';
 import { getOpenAIApi, authChat } from '@/service/utils/chat';
-import { ChatItemType } from '@/types/chat';
 import { httpsAgent } from '@/service/utils/tools';
+import { ChatItemType } from '@/types/chat';
+import { jsonRes } from '@/service/response';
+import type { ModelSchema } from '@/types/mongoSchema';
+import { PassThrough } from 'stream';
 import { modelList } from '@/constants/model';
 import { pushBill } from '@/service/events/pushChatBill';
 
 /* 发送提示词 */
 export default async function handler(req: NextApiRequest, res: NextApiResponse) {
-  try {
-    const { prompt, chatId } = req.body as { prompt: ChatItemType[]; chatId: string };
-    const { authorization } = req.headers;
+  let step = 0; // step=1时，表示开始了流响应
+  const stream = new PassThrough();
+  stream.on('error', () => {
+    console.log('error: ', 'stream error');
+    stream.destroy();
+  });
+  res.on('close', () => {
+    stream.destroy();
+  });
+  res.on('error', () => {
+    console.log('error: ', 'request error');
+    stream.destroy();
+  });
 
-    if (!prompt || !chatId) {
+  try {
+    const { chatId, prompt } = req.body as {
+      prompt: ChatItemType;
+      chatId: string;
+    };
+    const { authorization } = req.headers;
+    if (!chatId || !prompt) {
       throw new Error('缺少参数');
     }
 
@@ -22,13 +40,29 @@ export default async function handler(req: NextApiRequest, res: NextApiResponse)
 
     const { chat, userApiKey, systemKey, userId } = await authChat(chatId, authorization);
 
-    const model = chat.modelId;
+    const model: ModelSchema = chat.modelId;
 
-    // 获取 chatAPI
-    const chatAPI = getOpenAIApi(userApiKey || systemKey);
+    // 读取对话内容
+    const prompts = [...chat.content, prompt];
 
-    // prompt处理
-    const formatPrompts = prompt.map((item) => `${item.value}\n\n###\n\n`).join('');
+    // 上下文长度过滤
+    const maxContext = model.security.contextMaxLen;
+    const filterPrompts =
+      prompts.length > maxContext ? prompts.slice(prompts.length - maxContext) : prompts;
+
+    // 格式化文本内容
+    const map = {
+      Human: 'Human',
+      AI: 'AI',
+      SYSTEM: 'SYSTEM'
+    };
+    const formatPrompts: string[] = filterPrompts.map((item: ChatItemType) => item.value);
+    // 如果有系统提示词，自动插入
+    if (model.systemPrompt) {
+      formatPrompts.unshift(`${model.systemPrompt}`);
+    }
+
+    const promptText = formatPrompts.join('</s>');
 
     // 计算温度
     const modelConstantsData = modelList.find((item) => item.model === model.service.modelName);
@@ -37,42 +71,95 @@ export default async function handler(req: NextApiRequest, res: NextApiResponse)
     }
     const temperature = modelConstantsData.maxTemperature * (model.temperature / 10);
 
-    // 发送请求
-    const response = await chatAPI.createCompletion(
+    // 获取 chatAPI
+    const chatAPI = getOpenAIApi(userApiKey || systemKey);
+    let startTime = Date.now();
+
+    // 发出请求
+    const chatResponse = await chatAPI.createCompletion(
       {
-        model: model.service.modelName,
-        prompt: formatPrompts,
+        model: model.service.chatModel,
         temperature: temperature,
-        // max_tokens: modelConstantsData.maxToken,
-        top_p: 1,
-        frequency_penalty: 0,
-        presence_penalty: 0.6,
-        stop: ['###']
+        prompt: promptText,
+        stream: true,
+        max_tokens: modelConstantsData.maxToken,
+        presence_penalty: 0, // 越大，越容易出现新内容
+        frequency_penalty: 0, // 越大，重复内容越少
+        stop: ['。！？.!.', `</s>`]
       },
       {
+        timeout: 40000,
+        responseType: 'stream',
         httpsAgent
       }
     );
 
-    const responseContent = response.data.choices[0]?.text || '';
+    console.log('api response time:', `${(Date.now() - startTime) / 1000}s`);
+
+    // 创建响应流
+    res.setHeader('Content-Type', 'text/event-stream;charset-utf-8');
+    res.setHeader('Access-Control-Allow-Origin', '*');
+    res.setHeader('X-Accel-Buffering', 'no');
+    res.setHeader('Cache-Control', 'no-cache, no-transform');
+    step = 1;
+
+    let responseContent = '';
+    stream.pipe(res);
+
+    const onParse = async (event: ParsedEvent | ReconnectInterval) => {
+      if (event.type !== 'event') return;
+      const data = event.data;
+      if (data === '[DONE]') return;
+      try {
+        const json = JSON.parse(data);
+        const content: string = json?.choices?.[0].text || '';
+        if (!content || (responseContent === '' && content === '\n')) return;
+
+        responseContent += content;
+        // console.log('content:', content);
+        !stream.destroyed && stream.push(content.replace(/\n/g, '<br/>'));
+      } catch (error) {
+        error;
+      }
+    };
+
+    const decoder = new TextDecoder();
+    try {
+      for await (const chunk of chatResponse.data as any) {
+        if (stream.destroyed) {
+          // 流被中断了，直接忽略后面的内容
+          break;
+        }
+        const parser = createParser(onParse);
+        parser.feed(decoder.decode(chunk));
+      }
+    } catch (error) {
+      console.log('pipe error', error);
+    }
+    // close stream
+    !stream.destroyed && stream.push(null);
+    stream.destroy();
 
-    console.log(`responseLen: ${responseContent.length}`, `promptLen: ${formatPrompts.length}`);
     // 只有使用平台的 key 才计费
     !userApiKey &&
       pushBill({
         modelName: model.service.modelName,
         userId,
         chatId,
-        text: formatPrompts + responseContent
+        text: promptText + responseContent
       });
-
-    jsonRes(res, {
-      data: responseContent
-    });
   } catch (err: any) {
-    jsonRes(res, {
-      code: 500,
-      error: err
-    });
+    // console.log(err?.response);
+    if (step === 1) {
+      // 直接结束流
+      console.log('error，结束');
+      stream.destroy();
+    } else {
+      res.status(500);
+      jsonRes(res, {
+        code: 500,
+        error: err
+      });
+    }
   }
 }