feat: Implement file upload and processing for listings

- Added `FileService` to handle buffer to base64 conversion and vice versa.
- Integrated `FileService` into `ListingService` to convert image buffers to base64 strings before queuing them for processing.
- Created `UploadListingImageDto` to define the structure of the image upload payload.
- Implemented `ListingProducer` to add image upload jobs to the queue.
- Implemented `ListingConsumer` to process image upload jobs, including converting base64 strings back to buffers.
- Registered `FileService` in `UtilitiesModule` and imported it in `ListingModule`.
- Added unit tests for `FileService` to verify buffer to base64 conversion and vice versa.

Author: jfjuanmiguel

src/app.module.ts

@@ -1,9 +1,10 @@
 import { Module } from '@nestjs/common';
 import { CoreModule } from './core/core.module';
 import { ListingModule } from './modules/listing/listing.module';
+import { UtilitiesModule } from './utilities/utilities.module';
 
 @Module({
-  imports: [CoreModule, ListingModule],
+  imports: [CoreModule, ListingModule, UtilitiesModule],
   providers: [],
   controllers: [],
 })

src/modules/listing/dto/upload-listing-image.dto.ts

@@ -0,0 +1,15 @@
+import { Listing } from '@prisma/client';
+import { IsInt, IsNotEmpty, IsString } from 'class-validator';
+
+export class UploadListingImageDto {
+  @IsString()
+  @IsNotEmpty()
+  base64File: string;
+
+  @IsString()
+  @IsNotEmpty()
+  mimeType: string;
+
+  @IsInt()
+  listingId: Listing[`id`];
+}

src/modules/listing/listing.module.ts

@@ -7,6 +7,7 @@ import { ListingConsumer } from './queue/listing.consumer';
 import { LISTING_QUEUE } from '../../core/queue/queue.constants';
 import { BullBoardModule } from '@bull-board/nestjs';
 import { BullAdapter } from '@bull-board/api/bullAdapter';
+import { UtilitiesModule } from '../../utilities/utilities.module';
 
 @Module({
   imports: [
@@ -15,6 +16,7 @@ import { BullAdapter } from '@bull-board/api/bullAdapter';
       name: LISTING_QUEUE,
       adapter: BullAdapter,
     }),
+    UtilitiesModule,
   ],
   controllers: [ListingController],
   providers: [ListingService, ListingProducer, ListingConsumer],

src/modules/listing/listing.service.ts

@@ -2,12 +2,14 @@ import { Injectable } from '@nestjs/common';
 import { CreateListingDto } from './dto/create-listing.dto';
 import { DatabaseService } from '../../database/database.service';
 import { ListingProducer } from './queue/listing.producer';
+import { FileService } from '../../utilities/file/file.service';
 
 @Injectable()
 export class ListingService {
   constructor(
     private readonly databaseService: DatabaseService,
     private readonly listingQueue: ListingProducer,
+    private readonly fileService: FileService,
   ) {}
 
   async create({
@@ -21,8 +23,11 @@ export class ListingService {
       data,
     });
     for (const image of images) {
-      // send image to queue
-      await this.listingQueue.createListingImage(image);
+      await this.listingQueue.uploadListingImage({
+        base64File: this.fileService.bufferToBase64(image.buffer),
+        mimeType: image.mimetype,
+        listingId: listing.id,
+      });
     }
     return listing;
   }

src/modules/listing/queue/listing.consumer.ts

@@ -1,18 +1,24 @@
 import { Process, Processor } from '@nestjs/bull';
 import { Job } from 'bull';
+import { UploadListingImageDto } from '../dto/upload-listing-image.dto';
 import { LISTING_QUEUE } from '../../../core/queue/queue.constants';
 import { BaseConsumer } from '../../../core/queue/base.consumer';
 import { LoggerService } from '../../../core/logger/logger.service';
+import { FileService } from '../../../utilities/file/file.service';
 
 @Processor(LISTING_QUEUE)
 export class ListingConsumer extends BaseConsumer {
-  constructor(logger: LoggerService) {
+  constructor(
+    logger: LoggerService,
+    private readonly fileService: FileService,
+  ) {
     super(logger);
   }
 
   @Process(`createListingImage`)
-  async createListingImage(job: Job<Express.Multer.File>) {
-    console.log(`createListingImage filename:`, job.data.originalname);
-    return job.data;
+  async createListingImage(job: Job<UploadListingImageDto>) {
+    const buffer = this.fileService.base64ToBuffer(job.data.base64File);
+    // TODO: upload file to Google Cloud Storage
+    // TODO: store respective Google Cloud Storage URL in database
   }
 }

src/modules/listing/queue/listing.producer.ts

@@ -2,12 +2,13 @@ import { Injectable } from '@nestjs/common';
 import { InjectQueue } from '@nestjs/bull';
 import { Queue } from 'bull';
 import { LISTING_QUEUE } from '../../../core/queue/queue.constants';
+import { UploadListingImageDto } from '../dto/upload-listing-image.dto';
 
 @Injectable()
 export class ListingProducer {
   constructor(@InjectQueue(LISTING_QUEUE) private listingQueue: Queue) {}
 
-  async createListingImage(image: Express.Multer.File) {
-    return await this.listingQueue.add(`createListingImage`, image);
+  async uploadListingImage(payload: UploadListingImageDto) {
+    return await this.listingQueue.add(`createListingImage`, payload);
   }
 }

src/utilities/file/file.service.spec.ts

@@ -0,0 +1,38 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { FileService } from './file.service';
+
+describe('FileService', () => {
+  let service: FileService;
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [FileService],
+    }).compile();
+
+    service = module.get<FileService>(FileService);
+  });
+
+  it('should be defined', () => {
+    expect(service).toBeDefined();
+  });
+
+  describe(`bufferToBase64`, () => {
+    it(`should convert a buffer to a base64 string`, () => {
+      const buffer = Buffer.from(`Hello, World!`);
+      const base64 = `SGVsbG8sIFdvcmxkIQ==`; // Base64 encoded string of 'Hello, World!'
+
+      const result = service.bufferToBase64(buffer);
+      expect(result).toBe(base64);
+    });
+  });
+
+  describe(`base64ToBuffer`, () => {
+    it(`should convert a base64 string to a buffer`, () => {
+      const base64 = `SGVsbG8sIFdvcmxkIQ==`; // Base64 encoded string of 'Hello, World!'
+      const buffer = Buffer.from(`Hello, World!`);
+
+      const result = service.base64ToBuffer(base64);
+      expect(result).toEqual(buffer);
+    });
+  });
+});

src/utilities/file/file.service.ts

@@ -0,0 +1,12 @@
+import { Injectable } from '@nestjs/common';
+
+@Injectable()
+export class FileService {
+  bufferToBase64(buffer: Buffer): string {
+    return buffer.toString(`base64`);
+  }
+
+  base64ToBuffer(base64String: string): Buffer {
+    return Buffer.from(base64String, `base64`);
+  }
+}

src/utilities/utilities.module.ts

@@ -0,0 +1,8 @@
+import { Module } from '@nestjs/common';
+import { FileService } from './file/file.service';
+
+@Module({
+  providers: [FileService],
+  exports: [FileService],
+})
+export class UtilitiesModule {}