FastGPT/src/pages/api/chat/chatGpt.ts
2023-03-24 10:22:08 +08:00

145 lines
4.5 KiB
TypeScript

import type { NextApiRequest, NextApiResponse } from 'next';
import { createParser, ParsedEvent, ReconnectInterval } from 'eventsource-parser';
import { connectToDatabase } from '@/service/mongo';
import { getOpenAIApi, authChat } from '@/service/utils/chat';
import { httpsAgent } from '@/service/utils/tools';
import { ChatCompletionRequestMessage, ChatCompletionRequestMessageRoleEnum } from 'openai';
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/bill';
/* 发送提示词 */
export default async function handler(req: NextApiRequest, res: NextApiResponse) {
const { chatId, prompt } = req.body as {
prompt: ChatItemType;
chatId: string;
};
const { authorization } = req.headers;
try {
if (!chatId || !prompt) {
throw new Error('缺少参数');
}
await connectToDatabase();
const { chat, userApiKey, systemKey, userId } = await authChat(chatId, authorization);
const model: ModelSchema = chat.modelId;
// 读取对话内容
const prompts = [...chat.content, prompt];
// 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: ChatCompletionRequestMessageRoleEnum.User,
AI: ChatCompletionRequestMessageRoleEnum.Assistant,
SYSTEM: ChatCompletionRequestMessageRoleEnum.System
};
const formatPrompts: ChatCompletionRequestMessage[] = filterPrompts.map(
(item: ChatItemType) => ({
role: map[item.obj],
content: item.value
})
);
// 如果有系统提示词,自动插入
if (model.systemPrompt) {
formatPrompts.unshift({
role: 'system',
content: model.systemPrompt
});
}
// 计算温度
const modelConstantsData = modelList.find((item) => item.model === model.service.modelName);
if (!modelConstantsData) {
throw new Error('模型异常');
}
const temperature = modelConstantsData.maxTemperature * (model.temperature / 10);
// 获取 chatAPI
const chatAPI = getOpenAIApi(userApiKey || systemKey);
let startTime = Date.now();
// 发出请求
const chatResponse = await chatAPI.createChatCompletion(
{
model: model.service.chatModel,
temperature: temperature,
// max_tokens: modelConstantsData.maxToken,
messages: formatPrompts,
stream: true
},
{
timeout: 40000,
responseType: 'stream',
httpsAgent
}
);
console.log('api response time:', `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');
let responseContent = '';
const pass = new PassThrough();
pass.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].delta.content || '';
if (!content) return;
responseContent += content;
// console.log('content:', content)
pass.push(content.replace(/\n/g, '<br/>'));
} catch (error) {
error;
}
};
const decoder = new TextDecoder();
try {
for await (const chunk of chatResponse.data as any) {
const parser = createParser(onParse);
parser.feed(decoder.decode(chunk));
}
} catch (error) {
console.log('pipe error', error);
}
pass.push(null);
const promptsLen = formatPrompts.reduce((sum, item) => sum + item.content.length, 0);
console.log(`responseLen: ${responseContent.length}`, `promptLen: ${promptsLen}`);
// 只有使用平台的 key 才计费
!userApiKey &&
pushBill({
modelName: model.service.modelName,
userId,
chatId,
textLen: promptsLen + responseContent.length
});
} catch (err: any) {
res.status(500);
jsonRes(res, {
code: 500,
error: err
});
}
}