add etag to cacheResult

console-api/src/update/update.controller.ts

@@ -3,6 +3,7 @@ import { UpdateService } from './update.service';
 import { ApiBody, ApiCreatedResponse, ApiOkResponse, ApiOperation, ApiParam, ApiTags } from '@nestjs/swagger';
 import { DepotDto } from '../dto/Depot.dto';
 import { Response } from 'express';
+import { createHash } from 'crypto';
 
 @Controller('update')
 @ApiTags('update')
@@ -17,7 +18,9 @@ export class UpdateController {
 
   private async cacheResult<T>(res: Response, prom: Promise<T>) {
     const result = await prom;
-    res.setHeader('Cache-Control', 'public, max-age=31536000, immutable');
+    const hash = createHash('sha512').update(JSON.stringify(result)).digest('hex');
+    res.setHeader('ETag', `"${hash}"`); // minio-compatibility requires quotes
+    if (res.getHeader('Cache-Control') === undefined) res.setHeader('Cache-Control', 'public, max-age=31536000, immutable');
     return result;
   }