api-server/src/modules/files/files.service.ts

import {
  Injectable,
  NotFoundException,
  ForbiddenException,
} from '@nestjs/common';
import { FilesRepository } from './files.repository';
import { StorageService } from '../../infrastructure/storage/storage.service';
import { CosStorageProvider } from '../../infrastructure/storage/cos-storage.provider';
import { CreateUploadUrlDto, CompleteUploadDto } from './dto';

@Injectable()
export class FilesService {
  constructor(
    private readonly repository: FilesRepository,
    private readonly storage: StorageService,
    private readonly cos: CosStorageProvider,
  ) {}

  async requestUploadUrl(userId: string, dto: CreateUploadUrlDto) {
    return this.storage.createUploadUrl(userId, {
      filename: dto.filename,
      mimeType: dto.mimeType,
      sizeBytes: dto.sizeBytes,
    });
  }

  async confirmUpload(userId: string, dto: CompleteUploadDto) {
    const info = await this.storage.verifyUpload(dto.objectKey);

    const parts = dto.objectKey.split('/');
    const originalFilename = parts[parts.length - 1];

    return this.repository.create({
      userId,
      filename: originalFilename,
      mimeType: info.contentType,
      storagePath: dto.objectKey,
      objectKey: dto.objectKey,
      bucket: this.cos.getBucket(),
      sizeBytes: info.size,
      checksum: dto.checksum,
    });
  }

  async getFile(userId: string, fileId: string) {
    const file = await this.repository.findById(fileId);
    if (!file) {
      throw new NotFoundException('文件不存在');
    }
    if (file.userId !== userId) {
      throw new ForbiddenException('无权访问该文件');
    }

    const downloadUrl = await this.storage.getDownloadUrl(file.objectKey!);
    return { file, downloadUrl };
  }

  async deleteFile(userId: string, fileId: string) {
    const file = await this.repository.findById(fileId);
    if (!file) {
      throw new NotFoundException('文件不存在');
    }
    if (file.userId !== userId) {
      throw new ForbiddenException('无权操作该文件');
    }

    await this.storage.deleteObject(file.objectKey!);
    await this.repository.delete(fileId);
  }

  async findByUserId(userId: string) {
    return this.repository.findByUserId(userId);
  }
}