feat(law,openai): AI요약 결과를 stream으로 전달받을 수 있도록 함

src/apis/laws/laws.controller.ts

@@ -1,4 +1,4 @@
-import { Controller, Param, Query, Get, ParseEnumPipe, Post, Body, ParseIntPipe } from '@nestjs/common';
+import { Controller, Param, Query, Get, ParseEnumPipe, Post, Body, ParseIntPipe, Res } from '@nestjs/common';
 import { LawsService } from './laws.service';
 import { ApiOperation, ApiTags, ApiParam, ApiBody, ApiResponse, ApiTooManyRequestsResponse } from '@nestjs/swagger';
 import { getLawListDto } from './dtos/get-law.dto';
@@ -11,11 +11,13 @@ import {
   LawSummaryResponseData,
 } from 'src/common/types';
 import { Throttle } from '@nestjs/throttler';
+import { Response } from 'express';
+import { OpenaiService } from 'src/shared/services/openai.service';
 
 @Controller('laws')
 @ApiTags('Laws')
 export class LawsController {
-  constructor(private readonly lawsService: LawsService) {}
+  constructor(private readonly lawsService: LawsService, private readonly openaiService: OpenaiService) {}
 
   @Get(':type')
   @ApiOperation({ summary: '판례/법령 목록 조회' })
@@ -57,8 +59,7 @@ export class LawsController {
     summary: '판례/법령 요약 조회',
     description: `
       '더 쉽게 해석'을 위한 요청을 보내는 경우, 마지막에 제공받았던 요약문을 body의 recentAssistMsg에 담아서 요청합니다.\n
-      '더 쉽게 해석' 요청인 경우, summary만 제공됩니다.
-      `,
+      '더 쉽게 해석' 요청인 경우, summary만 제공됩니다.`,
   })
   @Throttle(4, 60)
   @ApiParam({
@@ -188,4 +189,35 @@ export class LawsController {
   ): Promise<LawSummaryResponseData> {
     return this.lawsService.createLawSummary(type, id, requestSummaryDto.recentSummaryMsg);
   }
+
+  @Post(':type/:id/summary-stream')
+  @ApiOperation({
+    summary: '판례/법령 요약 조회 - stream version',
+    description: `
+      '더 쉽게 해석'을 위한 요청을 보내는 경우, 마지막에 제공받았던 요약문을 body의 recentAssistMsg에 담아서 요청합니다.\n\n
+      stream 버전은 요청에 대한 응답이 ReadableStream으로 제공됩니다.(요약 제목, 키워드 제외한 본문 요약 내용만 제공됩니다.)`,
+  })
+  @ApiParam({
+    name: 'type',
+    enum: SearchTabEnum,
+    description: 'prec: 판례, statute: 법령',
+  })
+  @ApiParam({
+    name: 'id',
+    description: '판례 또는 법령의 ID(판례일련번호/법령ID)',
+  })
+  async createLawStreamSummary(
+    @Res() res: Response,
+    @Param('type', new ParseEnumPipe(SearchTabEnum))
+    type: SearchTabEnum,
+    @Param('id', new ParseIntPipe()) id: number,
+    @Body() requestSummaryDto?: RequestSummaryDto,
+  ) {
+    const lawSummaryReadableStream: ReadableStream<Uint8Array> = await this.lawsService.createLawStreamSummary(
+      type,
+      id,
+      requestSummaryDto.recentSummaryMsg,
+    );
+    return this.openaiService.sendResWithReadableStream(res, lawSummaryReadableStream);
+  }
 }

src/apis/laws/laws.service.ts

@@ -272,6 +272,21 @@ export class LawsService {
     };
   }
 
+  async createLawStreamSummary(
+    type: SearchTabEnum,
+    id: number,
+    recentSummaryMsg: string,
+  ): Promise<ReadableStream<any>> {
+    const lawDetail = await this.getLawDetail(type, id);
+
+    const summaryReqMsgs = await this.generateSummaryReqMessasges(lawDetail, recentSummaryMsg, {
+      onlySummary: true,
+    });
+    const summaryReadableStream = await this.openAiService.createAIStramChatCompletion(summaryReqMsgs);
+
+    return summaryReadableStream;
+  }
+
   private async fetchTitleAndKeywords(
     summaryContent: StatuteDetailData | PrecDetailData,
     retryCount = 2,

src/shared/services/openai.service.ts

@@ -1,8 +1,10 @@
 import { BadRequestException, Injectable } from '@nestjs/common';
 import { OpenAI } from 'openai';
+import { Stream } from 'openai/streaming';
 import { ConfigService } from '@nestjs/config';
 import { encoding_for_model } from '@dqbd/tiktoken';
 import { TiktokenModel } from '@dqbd/tiktoken';
+import { Response } from 'express';
 
 @Injectable()
 export class OpenaiService {
@@ -27,6 +29,47 @@ export class OpenaiService {
     return chatCompletion;
   }
 
+  async createAIStramChatCompletion(
+    promptMessages: Array<OpenAI.Chat.Completions.ChatCompletionMessage>,
+  ): Promise<ReadableStream<Uint8Array>> {
+    const requestData = this.generateOpenAIChatRequestData(promptMessages);
+    const stream: Stream<OpenAI.Chat.Completions.ChatCompletionChunk> = await this.openai.chat.completions.create({
+      ...requestData,
+      stream: true,
+    });
+
+    const encoder = new TextEncoder();
+
+    const readableStream = new ReadableStream({
+      async start(controller) {
+        for await (const chunk of stream) {
+          const str = typeof chunk === 'string' ? chunk : JSON.stringify(chunk);
+          const bytes = encoder.encode(str);
+          controller.enqueue(bytes);
+        }
+      },
+    });
+
+    return readableStream;
+  }
+
+  async sendResWithReadableStream(res: Response, readableStream: ReadableStream<Uint8Array>) {
+    const reader = readableStream.getReader();
+
+    const readAllChunks = async () => {
+      const { value, done } = await reader.read();
+      if (done) {
+        res.end();
+        return;
+      }
+
+      res.write(value); // 클라이언트에 chunk data를 write
+      readAllChunks(); // 스트림이 소진될 때까지 재귀 호출
+    };
+
+    readAllChunks();
+  }
+
   private generateOpenAIChatRequestData(promptMessages: Array<OpenAI.Chat.Completions.ChatCompletionMessage>): {
     model: TiktokenModel | 'gpt-3.5-turbo-16k';
     messages: OpenAI.Chat.Completions.ChatCompletionMessage[];